Engineer in Progress

SpaceX Readies Falcon 9 Rocket---No, Not That One

noreply@blogger.com (Rob Davidoff) — Sat, 19 May 2012 02:48:00 +0000

The excitement of waiting to see a launch can do strange things to me. Tonight, it can make me fall asleep at 6 PM, instead of my more usual midnight to one AM, so I can get sleep before the upcoming SpaceX CTOS-2+ launch. It can make me so excited that I woke back up after just three of the five hours I'd hoped to spend asleep. And, apparently, it can spur me to blog for the first time in...a while. Anyway, I'm probably going to be sharing several pictures of Falcon 9 and Dragon tonight, but I have some special ones first. THESE ARE NOT COTS-2+. This is the next Falcon 9, whose first and second stages are already in storage at a site near the SpaceX launch complex at LC-40 (specifically an old Delta facility, Hangar AO). There's only room for one rocket at a time in the main SpaceX integration hangar, and right now COTS-2+ is filling it (well, not right now, since it's rolled out to the pad, but it has dibs :) ). Hangar AO serves as a surge facility, letting them store hardware that won't fit in the main hangar until it's actually needed or there's room for it.

If all goes well tonight, in the next few weeks this hardware will be sitting where the COTS-2+ rocket was a few days ago, being readied for the next launch. Similarly, another Dragon is being completed at SpaceX's factory at Hawethorne. If tonight's launch and the coming mission goes well, that flight could become CRS-1, the first operational commercial launch to ISS. Otherwise, it becomes COTS-3, a third demo flight to prove that they can fix whatever the forces of Murphy's law might throw at them on COTS-2+. As I hear, that would be planned for August or September--driven by the time to finish preparing the Dragon and for a hole in the ISS's packed visiting vehicle schedule.

For SpaceX, the next critical goal after flying Dragon to ISS is to demonstrate that they can achieve the kind of flight rate needed to satisfy both NASA's CRS cargo contracts and the contracts they have to launch satellites for research, communications, and navigation. To do this, they have to step up their game in terms of launch rate and production. Having this hardware at the Cape already is one small step in that direction.

Status Update, February 2012

noreply@blogger.com (Rob Davidoff) — Tue, 28 Feb 2012 05:57:00 +0000

Well, it's been a while. No excuses, I'm not going to lie to a blog basically no one but me reads, but I've just had other things on my mind. What sort of things? Well, here's a basic rundown:

1) Work: Since late January, I've been working as a co-op for GE Aviation here in Cincinnati, in a Quality Control position at their Erlanger Distribution Center in Erlanger, KY. Despite the name, it's actually right next to the Cincinnati airport (CVG), mostly because the Cincinnati airport (for long and complex reasons I do not fully comprehend) is located in Kentucky. It's been pretty cool, chief among the attractions being that it's a workplace where I can sit in the break room at lunch and see airplanes powered by the engines I'm chasing parts for take off and land just down the hill and across the airport boundary fence. I'm not allowed to take my own pictures, so this is roughly the view I have, except further back and slightly higher up so I can see the runways.

Anyway, it's been a great experience so far, and I'm looking forward to continuing there for the rest of the summer.

2) Aerodesign Team: As with the last two years, I've once again been a member of the University of Dayton Aerodesign team. This year, I was leader of the Missions Group, responsible for all things rules and payload. I've also been pitching in a lot on the 60-page competition report, which we finally finished and submitted last week. As part of getting the report ready, we were pushing hard for a first flight so we'd have flight data for the paper. Unfortunately, the fuselage manufacturing team was delayed due to the long holiday break, and I was seriously worried we weren't going to fly before submitting the report. This was troubling because Dr Altman, our advisor, stated he thinks this paper may be one of the best we've submitted, and didn't want to see our performance in the scores at competition compromised by penalties for lack of flight data. Leslie, the team captain, managed to pull together the team and work a miracle at the 11th hour, and they got a prototype kludged together from the wings, tail, landing gear, and tail truss from this year's aircraft, combined with a fuselage ~~stolen~~ borrowed from a past aircraft.

It wasn't pretty, but it worked and we got the flight data we needed for the report. However, I think we definitely have a lesson to take away from this for next year: if the break is as long again as it was this year, at least a few members of the team must come back early to begin construction and ensure that sufficient buffer is allowed to absorb any slips and still allow flight before the paper is due. This plane flew two weeks ago, and again this week, generating some useful results about the lifting capacity of the wings and facilitated some messing with motor setup and props, but a more complete aircraft using the proper fuselage, improved wings and tail, and generally fully embodying this year's design is hopefully to be completed this week. I'm planning on going up later this week to help with that assembly and catch up on what I've been missing being away from campus.

3) Extracurriculars: In addition to all this, I've also had projects of my own. Chief among them lately has been Eyes Turned Skyward, an alternate history timeline I've been co-writing and publishing roughly weekly on the AlternateHistory.com forums. You may notice it's been running for a while, but this is the first I've felt up to talking about it on Engineer in Progress, largely because I'm aware it's probably full of amateurish technical mistakes and generally bad writing. Never-the-less, I'm pleased to say we've managed to reach nearly 27,000 views and over 400 comments on the 24 posts so far in the timeline, and we've received the Atomic Rockets Seal of Approval from Winchell Chung of the Atomic Rockets reference site, meaning we stand alongside works like Mass Effect 2, Orbiter, and the Beyond Apollo and Rocketpunk Manifesto blogs. Ah well. If we cannot be seen from afar, it is because we stand amid the ankles of giants. A lot of the reason I haven't been blogging much is that when I have been writing, it's been for this.

Official Atomic Rockets Seal of Approval, as received by Eye Turned Skyward.

Beyond working on Eyes, I've also been working on one final project. For the past year or so, I've been talking a good deal with Winchell Chung, and because of this he came to me for advice on preparing a poster showing off the jaw-dropping mesh he's done of the Polaris, from the "Tom Corbett, Space Cadet" series. He often uses the Polaris as an example, and he created a pretty detailed model of the Polaris as part of this. For this, he was kind enough to send me a copy of the final poster, which is currently hanging on the wall next to my desk. It's amazing, and the image below really can't quite do it justice.

Polaris Poster Thumbnail. See here to buy, or here for more on the Polaris.

In addition to the advice I provided on some details of the poster, I've also been providing some thoughts about revisions to the Polaris, including a rather substantial redesign of her pods. I provided a basic concept based on the role envisioned (basically to transit between the ship and stations while in orbit or as an inspection pod--kind of a useless role, but it's the best way we could find to rationalize the pods from the series). Compare the pod shown in the poster above to the draft concept I sent Winchell, and the amazing model he made based on that. I can't link them in here, but check the album out. It's been a fun little project. It's been particularly cool because Winchell's site is one of the main things that made me realize back in high school that rocket science was something I could actually do and made me decide that I did want to go down the aerospace engineering path that's taken me to where I am today. In a way, helping out with this has felt like paying that back.

Anyway, this ended up being a longer post than I thought it would be, so I'm tying it up here. Long story short, I've been doing some stuff that's kept me away from blogging for a while. I'm not sure that'll change anytime soon, but...I'll try to make time.

Ideas That Might Hold Water (Or at Least LOX)

noreply@blogger.com (Rob Davidoff) — Tue, 25 Oct 2011 22:45:00 +0000

Any regular readers I may once have had may notice it's been a bit sparse around here lately. In short, it's been because between classes, my OSGC research, and other projects, this blog has fallen down my list of priorities a bit. I'm planning to go into how that's been going in another post later, but the main reason for this post is that I got re-interested in an old idea of mine today and I thought it'd be worth writing up for Engineer in Progress. So let's talk about the SpaceX Dragon, and how I think it could be converted into a reusable fuel tanker for a fuel depot architecture.

I've very interested in the potential of depots in exploration architectures. It allows reusable orbit-to orbit spacecraft to be used for transits to the Moon or Mars, and allows missions that would require superheavy-class launch vehicles without depots to be staged with nothing more than existing or planned launchers like SpaceX's Falcon Heavy. For instance, on an Apollo lunar mission, the total hardware mass was only around 30 metric tons, but the total initial mass delivered to Earth orbit was 127 metric tons or so. This means that with a depot system for storage and transfer of cryogenic propellants, an Apollo-class mission could have been undertaken with 4 launches of a 30 ton vehicle. The lesson here is interesting particularly because of the capabilities of the Falcon Heavy and Falcon 9 Block II rockets (roughly 50 and 15 tons respectively) and their relatively low costs compared with past vehicles.

However, the need to fill such a depot requires a vehicle to serve the depot, a tanker. This vehicle will have to be launched as payload on a rocket, then be maneuvered to dock with depot and offload propellant. This creates two options. The first is a dumb stage, a tank that is inject to an orbit close to the depot, then grappled by a reusable space-only tug and moved to the depot. This makes the tank light, cheap, and ultimately disposable. The other option is a stage that's smart enough to fly itself, eliminating the need for the tug. However, this makes the stage an automated logistics spacecraft and thus expensive. Thus, if possible, it seems that such as "smart" spacecraft should be reused if possible.

In thinking about reuse of a "smart" tanker, I was inspired by the concepts for using modified Delta IV upper stages as depot components like the image shown above. It seemed like fairing over the tank structure could create a capsule-like shape. Covering this with a thermal protective system could allow a ballistic entry into the atmosphere for reuse. However, this require a lot of modifications, since the Delta IV 5-meter upper stage shown as a depot component in that image isn't intended for long-term use or reuse,. Thus, adding proper maneuvering control and thermal protection might be very challenging. Turning a lightweight tank stage into a capsule might be a bridge too far: too hard, too heavy, too expensive.

However, what about turning an existing capsule into a tanker? SpaceX's Dragon had always been my mental image of the final product due to the steep sidewalls that would be dictated by the Delta IV stage design. However, since liquid oxygen has a density of about 1.2 tons per cubic meter, a tank filling the payload margin for a Dragon would also roughly equal the pressurized volume. With a 16 ton-to-orbit Falcon 9 Block II and the 4.5 ton mass cited for Dragon on Wikipedia and in some SpaceX materials, this leaves room for 11.5 tons of LOX, which would have a volume of about 9.5 cubic meters. this fits nicely in the 10 cubic meters of pressurized volume on-board a Dragon. thus, it's possible that the only work needed to turn Dragon into a Dragon LOX Tanker would be to add insulation and an internal tank inside what is currently the pressure hull, and add systems to fill this tank on the ground and empty it into the depot on-orbit. The primary structure could remain largely unchanged, as could the Draco thrusters and the capsule's control systems. Dragon's thermal protective system has already been designed to be capable of multiple flight, so I think it's possible that after factoring in all the costs, this could be a competitive alternative to expendable "dumb tanks" both per-flight and on the more critical $/kg scale.

Dragon Pressure vessel being integrated with bulkheads for the un-pressurized hardware section containing thrusters and other equipment. In a Dragon Tanker, this pressure volume would contain the LOX tank.

As to why I suggest a single-fluid tank (LOX only) instead of carrying both a fuel and LOX, there's a couple of reasons. First, while the idea could work with two tanks (one for LOX, one for fuel), kerosene and methane are both less dense than LOX (70% and 37% as dense respectively) so a Dragon spacecraft carrying a full 10 cubic meters of mixed kerosene/LOX or methane'LOX might not be taking full advantage of the launch vehicle's capabilities, Liquid hydrogen is so much less dense (only 6% the density of LOX!) that it's not even worth thinking about. (On a side note, this low density is why despite the fact that only 16% of the mass of a hydrolox rocket's propellant is hydrogen, the hydrogen tank is usually several times the volume of the LOX tank. See the Space Shuttle external tank, the Saturn IV-B stage used in Apollo, or the Delta IV upper stages used in the depot shown above.) This means I don't think the added complexity justifies the gains.

This is especially true in my mind in light of the fact that for almost all liquid rockets, LOX makes up far more of the mass than does the other fuel. For instance, 100 tons of fuels for a kerolox rocket would consist of only 30 tons of kerosene, while a similar mass of hydrogen/LOX fuels would be 16 tons of hydrogen. A depot storing LOX could serve to "top up" stages launched carrying fuel only whether they burned kerolox, methalox, or hydrolox, while being substantially less complex due to the need to only handle and store one fluid.

Anyway, in short, Dragon is an existing multi-role vehicle that I think might adapt well to serving as a cheap, reusable LOX tanker as part of a depot-based exploration architecture. I think it'd be an interesting trade study to compare in more detail the cost per kg of fuel of a "dumb" expendable tank system versus a modified Dragon Tanker like I've described above, but I don't know that the data do do so is available publicly.

How I Spent My Summer Vacation (By Rob Davidoff, Age 20)

noreply@blogger.com (Rob Davidoff) — Mon, 12 Sep 2011 19:56:00 +0000

It has recently come to my attention that, despite the evidence to the contrary evidence of the post rate here at Engineer in Progress, I am in fact not dead. In fact, with the start of the school year, I’ve actually had time to do things, even! With that, I thought it would be worth bringing everyone up to date on my summer and what I’ve managed to get checked off of the To-Do List of All Dooms.

In this post, I’d like to talk a bit about what I did this summer (a topic that makes me feel like I’m making a presentation in second grade). As you may recall, I spent this summer as a test engineering intern at Ferno-Washington in Wilmington, OH. I meant most of the summer to write a post describing what exactly what that meant, what it involved, and what I felt I was learning, but unfortunately between my mom’s health issues, the commute to work, and other complications, I never had the time. So let’s start things with that.

"So what is test engineering?", I hear you ask (unless you're part of the 50% of my traffic that's just here for the pictures, in which case you'll be more interested in the diagram of the BA-2100 in another post planned for later this week). I'm glad you asked. Basically, test engineering is involved with the testing required to test various design concepts during engineering development, and then to validate design prototypes against internal and external standards to ensure that the final product can do what it needs to do. If design engineering is about making solutions to problems, test engineering is involved in picking the best solutions and making sure the solutions work as intended under varied conditions.

This meant a lot of dealing with paperwork, and a lot of dealing with standards. In doing this, I came to some realizations about the two. This summer at Ferno, my major responsibilities were processing test requests from design engineers, carrying out and documenting the testing, then preparing formal reports about the test, which meant I had a lot of experience with paperwork. In my ten weeks at Ferno, I participated in closing out about 30 tests, which included both ones I performed in addition to ones that had been performed prior to my arrival, but which had my boss had not had time to document himself. In both cases, while preparing the formal test reports, I depended extensively on photographic and written documentation of the events of the test. And the reports themselves had value: for many reports, we would refer during the test planning stages to setup descriptions of similar tests in the past to ensure that our methods were consistent with the past setups.

Standards also played a major role in my summer work at Ferno. In testing, the question that was always asked about a new test request was the purpose of the test--what was intended to be learned. Was it to compare several design solutions and find the "best"? Was it intended to determine whether a prototype was capable of performing as desired? In all these cases, standards played a critical role in planning the test and evaluating the test results. These standards could be regulatory, part of the standards that Ferno's products had to meet to be certified for use in the demanding conditions emergency equipment may encounter, or they could be internal standards to ensure that the product also provides users with the quality they rely on. In dealing with these standards in testing, I came to better appreciate the need to have such standards. Without a defined standard to test to, a test really isn't informative. The standards themselves must be meaningful (testing to proof or ultimate loads or simulating field conditions), but a test done to a meaningful standard is far more meaningful than one without a defined standard.

All in all, I really enjoyed my time at Ferno. I was lucky that most of my co-workers were friendly and easy to work with, and I feel like I made a valuable contribution during my time there. When I arrived, the test report backlog had grown to more than thirty reports, on the day I left it had been reduced to six, none more than a week removed from the date of test completion. I feel like I learned a lot more about the purpose of testing in engineering and what makes a test valuable, and I look forward to carrying these lessons on with me, both to the Aerodesign team this school year and on to other areas of my professional career. So, yeah, that's what I did this summer. I have more to say about what I've been up to since my last day at Ferno, but since this post is already pretty long, I'll leave it for another time.

Free Time? What Free Time?

noreply@blogger.com (Rob Davidoff) — Thu, 30 Jun 2011 00:13:00 +0000

It's been busy for me, between work and some health issues for my mom, so I haven't had as much time to blog as I might have liked. That's as far as I'll go towards making excuses for my lack of posts the last week or two. However, that's not to say I haven't been working on stuff, just not much and not for very long at a time, and I haven't had any time beyond those work periods to write about them. On that catch-up note, here's an entire project of mine I've yet to even have the chance to talk about here.

About two weeks ago, I was contacted by someone who wanted some help rendering something. You may have heard of the Nautilus-X spacecraft proposal, a design for a long-term reusable orbit-to-orbit vehicle, built in multiple launches using ISS operational experience. The most striking feature for many people is the centrifuge ring, which is spun to create the illusion of gravity. This tends to excite space fans, since centrifuges have this whole air of sci-fi about them, and yet are still plausible, except for all the messy little engineering details like making the plumbing and wiring work across a rotating interface or the effects on maneuvering of essentially having a 30 ton gyroscope mounted to your ship.

Nautilus-X, front perspective view showing centrifuge ring

Nautilus's centrifuge is interesting because it proposes to use inflatable structures for much of the ring. It consists of a rigid hub, connected by a rigid passage tube to a rigid ring section. The ring itself is a mix of such rigid sections linked by inflatable sections (the other two rigid sections are connected by extending trusses to the hub, and serve to help support the ring in spin). Compacted, it's a very tight package, and makes good use of the rigid components where rigid is of benefit and inflatable where inflatable is best. On-orbit, the trusses would extend the ring sections, then the ring would be inflated and fitted out with habitat equipment: sleep stations, communal living areas, perhaps a sickbay or other equipment where gravity would pay off. The idea is interesting, if a bit of what Robert Zubrin would call a "Battlestar," an over-complicated slightly over-built spacecraft, but it's a big dream and I like those. The images of a test centrifuge attached to the ISS as a tech demo especially appeal to me. I've often lamented the loss of the funding for the Centrifuge Accomadations Module, and the lack of really good data on the reaction of the human body to varying gravity levels (including prolonged sub-Earth levels, like a Mars colony might have) and the rotation rates possible before biology and gravity gradients become an issue. With these two pieces of data, it'd actually be possible to design a 2001-style station or a spacecraft like the Discovery (or indeed Nautilus) with some kind of artificial gravity centrifuge.

Demo Centrifuge at ISS

The person who contacted me asked if I might be willing to try to render a conceptual cutaway of the interior of the ring. I used to spend days in middle school doodling diagrams of spacecraft and drawing scale floor plans of them, so this appealed to me, especially since it'd be a nice chance to press my modeling chops. It seemed like a fun thing to try and do--design a possible interior in a relatively small-diameter rotating centrifuge. I should be clear that neither he nor I has any real idea of the internal layout of the Nautilus, I'm not sure one exists at this time, despite all the nifty images of the ISS demo module. Thus, the following is only my best guesses, and as much informed by the design of boats and mobile homes as by valid spacecraft design principles. I hope Winchell Chung can forgive the transgression the previous sentence represents, but it's about the best I can do for the moment. Engineer in progress, it says so in the title.

Anyway, so to start, I needed to establish the physical parameters of the ring. It has been stated in presentations of the concept to have a diameter of 60 feet, and from the image above, scaling from the core (stated in another slide to have a width of 6.5 m), the ring's minor exterior radius looks to be about 4 m or so. Taking into account inflatable walls with a thickness of 16 inches, on the order of Bigelow's designs, this produces an interior diameter of about 134" (Yes, Imperial units. Deal with it. I did.). This gives a volume of around 425 cubic meters, about right for 6 people's occupation for up to two years. It's worth noting that combined with timing this animation of Nautilus (yielding 10 seconds per spin, or 6 RPM), the ship is basically designed to yield Martian gravity: 1/3 Earth gravity.

Cross-sections of Ring

To create the interior of this ring, I defined a flat floor as shown above, based on a minimum overhead of 6 feet. I show a centerline passage of 36" and a passage going past a partitioned room (shown with 36" bed), with 30" of floor space, and some extra elbow room. I then broke down the ring into rooms using these arrangements, and created the design below in Adobe Inventor. The "roof" level is a 78" ceiling: enough to give some head room even for tall people like myself, but not quite towering. With all the area under the floor available for use by utilities, I think that when I get around to modeling a ceiling, it'll be much more of narrow enclosed (?) utility run along the middle than the illustrated flat surface at 78" above the floor, a duct as opposed to a drop ceiling.

Attempt at Nautilus Floor Plan

Click Image for Full Size

After some refinements and modifications based on discussion with the person who requested the work, I was satisfied enough to begin rendering the ring in Inventor. I rendered each portion (cabins, heads, the mess/galley area, the gym, stowage, the lab and medical bays) separately, so I could assemble them in any order, and so that changes to any on of duplicated rooms like the heads or the cabins would be reflected in all of them with the click of a mouse the next time I opened the assembly. Some rendered animation of the model are below (my first attempt at it with Inventor and it kind of shows--note for future: floors and background should contrast more). I'm hoping to refine both the model and my method of showing it off a bit more, but I'm pretty happy with the start of it.

View One (Click to play)

View Two (Click to play)

Good News and Bad News

noreply@blogger.com (Rob Davidoff) — Wed, 15 Jun 2011 03:02:00 +0000

So, as the title suggests, I have some good news, and I have some bad news that it'll be bringing with it. The good news is that as I mentioned last post, my summer suddenly became a bit busier than I was worried it might end up. After a lot of job searching, I accepted an offer of a summer position with Ferno-Washington Inc. of Wilmington, Ohio.

Ferno is a global leaders in the manufacture of EMT and mortuary equipment, and as a test engineering intern in their R&D department, I'm going to be helping make sure that their products are as good as they can be. It's an interesting experience in reliability engineering, and I think it'll be a good experience for me as an engineer. I'm working on some very cool products with some very interesting people, but since I'm unfortunately now on the inside of one of those corporate confidentiality agreements I've lamented in aerospace in the past, I can't say much beyond how fun it is to be running automated endurance testing of products, or doing qualifying testing on new or modified products to test their adherence to the designed, specced, or regulated capabilities. I'm hoping to find ways to talk about more general topics that occur to me in the course of my time with Ferno without talking about details that might constitute breaches of confidentiality--more reflection on the thoughts my job is bringing than the details of the work I'm doing--but I'm not sure if that's kosher yet, so don't expect to hear more about the job yet.

Which brings me to the other part of the title: the bad news. The Ferno facility in Wilmington is an hour commute one way, and as a result I'm going to have even less time for blogging than I had during the school year. I do have aerospace side projects going on that I hope to continue working on, including revisions to the Transhab Calculator, but many nights it's going to be a choice between working on them, or talking about working on them. I'll be trying to post at least once a week, but we'll see. I've got a batch update on what I've been up to over the last two weeks coming (indeed, this was originally the first few paragraphs of it), but it'll be a day or two.

Anyway, if this post seems lacking in aerospace material to you, allow me to present the game I spent much of the first few days of work playing: Name that Plane! See, Ferno's facility is located at an industrial park built around the former Clinton County Air Air Force Base (now the Wilmington Airborne Airpark), and there's a fighter parked on the road into the industrial park. I knew when I first saw it that it was an early jet, it just has the look that only the Century Series has, but despite several mental notes every time I drove past, I kept forgetting to look up what it actually was. Take a look through the pictures, and see if you can figure it out. (Answer below picture set.)

NACA Ducts! These are nifty things.

Wing fence visible on upper wing surface.
These were very common aerodynamic fixes in this era, both on Western and Soviet aircraft.

The plane is a McDonnell F-101 Voodoo, an interceptor fighter of the mid-50s, and a relative of the later and more famous F4 Phantom, which was one of the primary US aircraft of the Vietnam War era.

Imagined Images and Reality

noreply@blogger.com (Rob Davidoff) — Thu, 09 Jun 2011 03:41:00 +0000

So, you may already heard this (curse my sudden lack of free time!), but the STS-134/International Space Station images are finally in. The image NASA's been promoting the heck out of (and rightfully so, I think) is below, showing the station from the port side, with the shuttle and the station's truss and modules both very visible.

Click image for mondo big version

For those interested, many others from the same astounding set can be found on the NASA.gov site here. Personally, I think I have enough new backgrounds to last for months if not years. (Also see the video here, for some more amazing content.).

This is truly an amazing and historic moment, but looking at it and thinking about why it is, it reminded me of an image I posted a while back here on Engineer in Progress. No, not Kieth McNeills's amazing model images of what an STS-133 flyaround might have looked like (now with side-by-side comparisons with the real thing on NASAspaceflight's forums here). Something earlier.

Is it the STS-71 Mir image, taken in a similar fashion to the ISS imagery sequence?

No, it's not. It comes from even slightly before that. See below:

That's not the ISS there. That's an artist's conception of the American Space Station Freedom, from the mid-80s to the early-90s, the station which morphed into the core of the American portion of the station. So the Shuttle-docking-to-station image has legs. Why? Because this is what the Shuttle was about, about building and servicing a large space outpost, where various types of science could be performed, from life sciences, materials experiments, astronomy (early SSF proposals included an attached telescope observatory), and technology demonstrations for revolutionary new space hardware (in it's day, they were looking at stuff like solar thermal power generation).

Basically, only in the last few years has the ISS has actually started to do that. The AMS-02 instrument is amazing, but it's only now at the end that it's finally flown. Proposals are circulating to test BEO technologies like VASIMR, inflatible habitats or closed-cycle life support systems on ISS (the ISS water-recycling system is sort of part of that, and that's been going for a few years now, I guess.). And now, finally, after almost 20 years, it's finally happening. That's what I see when I look at the images of Endeavor docked to ISS: the culmination of a 20-year dream.

What's next? Where does spaceflight go from here? I wish I knew. I wish anyone knew--the whole situation with the SLS (Space Launch System, a congressionally-mandated new heavy lift vehicle) is so convoluted, politically-and-emotionally-charged and multi-polar I don't think I can adequately state what the situation is, but it's there. There are also the multitude of dreams offered up by Bigelow, SpaceX, XCOR, Armadillo, Masten, Altius, and many other commercial space companies. In 20 years, which of these dreams will be a reality, and will it take all 20 to make it happen? I wish for as many of the former as possible, and hope not the latter on any. But we'll just have to see. I just wish the space program of the next decade could amaze me and my generation in ways the space program of the last 50 occasionally has amazed past generations, and continues to amaze those of us who care to research it. That's all I want to say, just go back up and enjoy all the links.

Mistakes Were Made

noreply@blogger.com (Rob Davidoff) — Thu, 26 May 2011 03:59:00 +0000

Longtime readers (let's pretend for a moment that such a thing exists) of this blog may recall past posts about Bigelow Aerospace, my excitement about their technologies, and my attempts at creating a Transhab Module Calculator capable of roughly approximating possible Bigelow modules. Today, Bigelow broke it's veil of corporate secrecy and allowed a copy of some charts the founder, Robert Bigelow, presented at the International Space Development Conference to be posted at a few sites. Engineer in Progress was not one of those sites, so I can't present that data, but what I can present is this finely-crafted hyperlink to the presentation on SpaceRef, one of the sites that was allowed to post it.

Naturally, after I got done geeking out about the technical details, one of the first things I considered was the specifications presented for the BA-2100 (now dubbed "Olympus," which I think is appropriate for a module that has greater volume than Skylab, Mir, and the International Space Station added together) and whether they fit my calculator's predictions. The results were troubling: the calculator underestimates the module's volume by almost 300 cubic meters, and overestimates the mass by almost 20 metric tons even on my lowest predicted equivalent density.

This error was pretty significant, and so I decided to double-check the calculator against the provided figures for the BA-330. This module was one of the ones I used to calibrate the calculator when I originally created it, so it was perhaps even more troubling that the predictions were also off for the BA-330: The volume was low by almost 100 cubic meters, an underestimate by almost a third.

Therefore, until I've had a chance to look over the new data and diagrams, re-examine my assumed model parameters, and put everything together, I'm retracting the model. I'm going to have to figure out what to do about the calculator (what's wrong, whether I can fix it, and what to do in the meantime), but I wanted to put this out there.

tl;dr: I've found some mistakes in my model based on new data. It's down until I can fix them to my satisfaction.

Been So Long: Soyuz Fly Around at Last!

noreply@blogger.com (Rob Davidoff) — Mon, 23 May 2011 21:44:00 +0000

Well, I know it's been a while since I checked in--I've been busily trying to figure out what I'm going to do this summer. Getting turned down for co-ops all day is hard work. Anyway, I've also been avidly following the STS-134 mission, which featured the installation of the AMS-02 experiment unit on the station truss, and an unexpected but welcome addition: the Soyuz fly-around photo opportunity originally scheduled for STS-133.

On that flight, the Soyuz was the first of a new type, which meant that the Russians did not feel comfortable using it for the proposed photo. However, the Soyuz that is today being used is of the older type, and as a result even as I write this the Soyuz is separating from the station and backing off to take images of the now-finally complete station (well, except for the Russian MLM and node, anyway) and the Space Shuttle Endeavor on that vehicle's final flight. Astronaut Paulo Nespoli will be taking pictures and imagery of the station over the next half-hour or so. For more information, I recommend checking out NASA TV and Nasaspaceflight, my favorite place for space news updates. Engineering imagery of the station from the Soyuz are currently showing on NASA TV, and it's a great prelude of the full images we should get from this unique and historic opportunity.

Soyuz has rolled to re-orient station in camera view, station about to begin a maneuver to give Soyuz a better view of the station. Video apparently also being taken, which should be astounding.

That maneuver now in progress:

Pluming visible on the Soyuz as it maneuvers to keep station.

The imagery from the cameras Nespolia is operating should be amazing, just the engineering views from Soyuz are amazing. Can't wait!

I've Been Working on the Railroad

noreply@blogger.com (Rob Davidoff) — Tue, 10 May 2011 18:18:00 +0000

Just to pass the time away, of course. Anyway, I reserve the right to use Engineer in Progress to ruminate on ideas I like, and last night I saw a really interesting one. Ray MacVay, from Blue Max Studios (makers of the hard-scifi RPG Tales of the Black Desert), made an interesting post entitled Artificial Gravity and What Rollercoasters Can Teach Us, and it solidly engaged what someone of my acquittance once called my "turbonerd" mode. The proposal is to use self-propelled train-like cars moving around a fixed circular rail for large spin-gravity spacecraft, instead of a large rotating structure. I'm not really explaining it well, and he does a much better job, so...go read the original post. I'll wait.

Seriously, go check it out. It has pictures.

Done? All right, let's talk the engineering of such a system. First of all, I like a lot about it. Air doesn't need to cross the spin division because entire cars do, presumably each with on-board life support, water reprocessing, and that stuff. Power and data are a bit trickier--unless the cars have their own on-board power generation, then electrical power will still have to be sent to the cars with slip rings, and data will have to be sent from car to car either with a wireless network or (if wired is preferred) another slip ring setup. Still, it's an interesting modular system. Still, there's one or two things that need work.

First is that I'm not sure about having the spin rails out on pylons from the sides as they are above. They're going to be fairly beefy, and then they have to also support the modules going around the track. Why is this an issue? Time for a structures lesson. Imagine a ship under thrust, consisting of an engine, a support truss (A&B) and two spin rings on pylons (C&D). Essentially, this is a simplified version of Ray's IPV design.

Might look something like this

Under thrust, the structural loads on A and B will be compressive, that it that the forces are along the axis of the beam, trying to push it to make it shorter. This isn't bad--metals' not half bad at compressive, it's why the use of steel was key to early skyscrapers. However, on C and D, the load is perpendicular to the axis of the beam, so instead of being a compressive load, it's a shear load. If you imaging the metal as being sort of flexible, you could imagine it bending like a spoon being used as an improvised catapult. Metal really does bend like that under shear loads (though not as dramatically as that spoon), and if you're going to be running rails on those beams, that's an issue. Thus, the first change I'd suggest would be to move the spin rings to being axial, like this:

In this configuration, the majority of the forces are now compressive, and the only shear-loaded members are the actual spin rail supports, which are shorter and can be more numerous, reducing the stress on any individual beam.

The other thing that bugged me about the concept was the sidetrack concept Ray introduces. On the one hand, it's nice since it allows people to move from the spin sections to the stationary sections (including radiation-shielded shelters for solar storms) without leaving their modules, which is very nice and worth having--it's an innovative thing, and one reason I like the concept. On the other hand, it means more complexity, and this requires consideration. First, since the rail section needs to keep it's center of mass placed properly, every car must be balanced by the other cars (two cars 180 degrees apart, 3 cars at 120 degrees, 4 at 90, ect....), and it makes sense to have the ability to take off or add two cars at a time from opposite sides to be able to maintain this balance. So instead of just one switch in the spin rail, you need two 180 degrees apart.

These switches will also need to be quick-cycling. If you have several cars going around your spin rail and you want to take off only one of them (or two, for balance), then you need to be able to cycle the switch to get the car off and cycle it back to the straight position before the next car comes through. To get an idea of just how fast they need to cycle, you need to know how fast the cars are moving and the number of cars on the rails. By my analysis of his drawings (like the one above), the life modules are about 4 m in diameter, and the spin ring track is about 28 m in diameter, for a spin radius of 18 m. Using SpinCalc, this gives the following figures for 1 G:

Run with Ray's size and 1g generated

So, this requires an angular velocity of 7 RPM, which is a bit too high. Re-running with a lower spin velocity (5 RPM, about the highest I'm comfortable assuming people can adapt to) and the same size parameters gives the following:

Run with Ray's size and 5 RPM

This gives only about half Earth gravity, which is possibly enough, though long-time readers may remember me lamenting that lack of real data on how much gravity is needed to avoid long-term issues. SpinCalc can also be used to see what spin radius would be needed for 1 g and 5 RPM:

Size required for 1 g with 5 RPM

As you can see, the spin radius has to be 35.77 m, which with the 4 m modules is a rail diameter of almost 70 m. This is...a lot. Going from 0.5 g at 5 RPM to 1 g at 5 RPM requires bumping the diameter up by basically a factor of 2. That's a pretty significant change and I think you can see why I believe good data on long-term human health at gravity levels between 1 g and microgravity is necessary if spaceflight is really going to be practical. Anyway, what does this mean for the switching speeds needed?

At 7 RPM, it takes about 8.57 seconds for a car to go around the track. With 4 cars on the track, the time between cars is only 1/4 that time, or 2.14 seconds. This is the margin that the switches have to cycle within. Even at only 5 RPM, the window with 4 cars on the rails is only 3 seconds-still very short. Can a switch be made for this? Maybe, but it's going to be tricky.

Anyway, moving on from the question of how the switches need to operate to how rails would need to be run. The track layout Ray shows on his example here basically can be though of as translating to the following diagram.

Diagram of Ray's basic tracks

The two spin rails are connected to one sidetrack each. As I said, there really need to be two switches on each spin rail so that modules can be kept balanced. This results in the following modified track diagram:

Modified Track Diagram

Here, I've added a second set of switches to each spin rail, and also a through track connecting the two side tracks. The connection allows a car to be easily moved from one sidetrack to the other, or for cars to be re-arranged with the switches. The switches are a bit more complex than the switches in the original version, but the system should be much more useful.

I also looked at possible track arrangements for axially-located spin rail like I suggested at the start. The best I came up with was the below. Note that the system is modular--it works for one, two, three, or more spin rings.

Track diagram for axial spin rail

Anyway, so that's basically everything I've got at the moment. To close, here's some pictures of something cool I saw when I was dropping by the Aerodesign wind tunnel on Friday. I was walking along, and I suddenly noticed that the cart that a guy was pushing out of the machine shop had something pretty nifty. They were metal cubes, but they were kind of different.

So, I stopped for a closer look. The cubes were 1 ft cubes of aluminum honeycomb, lots of little cells connected together. Apparently they were being prepared for some experiments involving flight data recorder crash survival, as targets. We've used honeycomb material in Aero team a little, but never metal, and never this thick (our would be more like a sheet, with the cells only about 0.125 to 0.25 inches deep). Anyway, it was nifty stuff, and I'm glad the guy was willing to stop and let me have a look.

Not-So-Shiny Metal

noreply@blogger.com (Rob Davidoff) — Mon, 02 May 2011 22:04:00 +0000

Well, the J2X blog has been having some amazing posts and images of their progress in readying the first J2X engine unit for testing, with both the engine and the test stand stand getting close to ready. Hopefully, things will continue to go well, and we might soon see this engine fire, the first good-sized hydrogen/oxygen engine (important for upper stages) to be developed in the US in quite some time.

J2X engine unit under assembly

Test stand A2, with J2X mass simulator in place

I'm not sold on the need for the J2X or some of the proposed applications. I've heard some arguments for it, I've heard some against, and none have completely convinced me. Still, it's really exciting getting the inside look at the development process that the J2X blog has been offering. The J2X is a modification of the J2, originally developed as the upper stage engine to send the Apollo missions to the moon. However, since changes have taken place in manufacturing techniques and theory in the days since the Apollo program and the J2 has been out of production for almost 35 years, the J2X is less of a modification of an old design and more a new engine that uses the same basic design. One example of this inspired the title of this post, the Shiny Metal post about exploring making use of additive manufacturing techniques to speed up construction and lower costs.

So...what does this all have to with me? Why post about it on Engineer in Progress? Well, it's cool new stuff in aerospace, and I like talking about that. However, it also reminds me of something that I've been working on with the University of Dayton Advanced Rocketry Team (UDART). I've been getting into the organization this year, and the last few days we've been doing some work on our own engine. If you look at my profile picture up on the top right, you'll see me holding the club's LR-101 rocket motor, taken at a presentation they did early in the year before I got involved (actually, that presentation was part of how I ended up getting involved, but that's not worth talking about).

The LR-101 is a liquid rocket engine that burns kerosene and liquid oxygen, and produces about 1,000 lbs of thrust. Just like J2X, the LR-101 has a rich history--while the J2 was developed as an upper stage engine for Apollo, the LR-101 was intended as a vernier steering motor for the Atlas missile--note the welded patches on the combustion chamber where the old gimbal system used to attach (see the image below for what an LR-101 looks like with that).

However, while the J2X is under development and testing to qualify new modifications, we want to test this engine to ensure it's still got enough of the old performance left for the application we'd like to use it in--as the main engine of a sounding rocket intended to reach up to 30,000 feet. To do this, we need to put the engine on a test stand, instrument the engine, and static fire it. The mount at the bottom of the engine in the picture above is part of the mount to the stand. Since I've been a bigger part of the team, I've made getting the test stand ready a priority of mine, and the last few weeks as I've had time away from Aerodesign have paid off handsomely.

UDART LR-101 test stand. Click Image for full size

The entire frame is designed so that we can load it into a pickup truck and move it to a site where we can actually fire the engine, as opposed to our lab next to Five Guys and Panera on Brown Street. At the site, we can then tie it down securely, but the main engine connections and others don't require further work at the site beyond verifying functionality. The way the system works is diagrammed below.

Digram of Propellant Systems

There are three tanks, one of the kerosene fuel, one of the oxygen, and one of high-pressure nitrogen. The nitrogen serves to pressurize the main tanks and force the reactants (the kerosene and oxygen) into the engine to be reacted. To fire the engine, we first open the pressurization valve to bring the tanks to pressure, then open the propellant valves and ignite the engine. The actuators for the valve assemblies can be seen above, though the ball valves themselves are sort of hiding behind the engine mounting plate. A better view of this section can be seen below.

Test stand from upstream. The valve assembly is at the bottom center of the photo.

The valve assemblies have been the focus of work for a while, first getting the pressurization actuator and valve mounted to the stand, and now refitting the main valves and getting them set up. I spent the last two meetings getting the kerosene valve (on the right above) properly and securely mounted to the frame of the stand so that it didn't move and was properly aligned with the oxygen valve next to it. This is required since the two are operated by a single hydraulic actuator--this means that if properly set, the two will be perfectly in-sync, but getting them synced and set up is a lot of work. Saturday, we finished that, mounted the engine as is shown above (including spacers representative of the load cells we'll use to measure the thrust of the engine when we test it), and started work on zeroing the valves.

The valves we use are ball valves, and to ensure proper operation, we have to make sure that the actuator moves them from completely closed to completely open, but doesn't try to go beyond these limits (to avoid deflection of the frame). To do this, we first adjusted the fitting between the actuator rod and the valve rotation link so that it is in the fully closed position when the rod is fully extended, then checked how long the rod needed to be when the valves were fully open. To stop the rod from getting any shorter than this, we have to insert a stopper, shown below.

Spacer/Stopper Rod, Checking Length After Cutting

This consists of a cylindrical piece of metal that goes around the actuator rod. When the rod retracts to the length we want to be the minimum (and corresponding to fully-open valves), the stopper will be stuck between the actuator cylinder and the fitting on the end of the rod, preventing any further retraction. To make this, we took a piece of metal stock that had the right outer diameter, and machined it to have the proper internal diameter. However, while the stock we had did have a hole in it, it was not only too small for the actuation rod to fit through, but in fact too small for the smallest boring bar we had for the lathe to fit into.

Original stock center hole size

Required final inner diameter

Thus, what we had to do was first drill out the center hole with a drill bit, then further increase the internal diameter with the boring bar until the internal hole was large enough to fit around the rod. However, there was one last issue--the boring bar was too short to fit all the way through the stopper size we needed. When we realized this, we had already spent several hours messing with the stand Saturday, so we decided to call it a night instead of taking the time to do the ten or so cuts it would take to do the other side.Thus, tomorrow, we have to turn the stopper around, and finish boring out the last few centimeters of the other side Actually, the images taken above are of the two ends of the same piece that will become the stopper, so you can see clearly what we have to do. Still, once this is done, we will be able to finalize the actuators, assemble the plumbing to the tanks, and leak test and check the entire system. Then, we just have to take the whole thing apart and clean it to be ready to test. The whole thing is a lot closer to operational than it used to be, and I can't wait to see the job through to static firing.

Shooting Gumballs

noreply@blogger.com (Rob Davidoff) — Fri, 29 Apr 2011 09:33:00 +0000

So, this is a recycle in a way. In the dim and distant past before I had a blog (read: last summer), a friend and I spent an interesting afternoon working out the answer to a scenario we came up with, and I thought it was fun, so I'm posting it here at Engineer in Progress. Let's say NASA and commercial comes through, the whole shebang. 4 commercial crew vehicles funded to completion by CCDEV (SpaceX Dragon, Boeing CST-100, SNC Dreamchaser, and Blue Origin's....thing). Between NASA and commercial, 4 man-rated US launchers (SLS, Atlas V, Falcon 9, Falcon Heavy). ISS is fully utilized, Bigelow gets things going on a commercial station, Astrobotic goes to the moon and wins the Google Lunar X-Prize (or some other comparable team does).

But you don't work for any of those companies. You don't build launchers, or capsules, or stations, or unmanned landers. You work for Space Supply Corp, Inc, Ltd and your division is bidding on a vending machine contract. Specifically, you're bidding to refill these critical pieces of equipment:

That is, gumball vending machines. Well, a version of them that doesn't use gravity feed. This isn't 2001, we don't have artificial gravity! This is near-term gumball-machine resupply contracting, after all. So...how much does an astronaut need to feed in to get out his gumball? Glad you asked!

The first question is shipment method. The average 1" gumball consists of a spherical shell about 1/8" thick, surrounding a central cavity that is approximately atmospheric pressure. This central cavity poses a problem: on the ground, the gumball does not experience a significant net pressure across the shell, since the air inside and outside are pretty similar (off by maybe a few kPa depending on the weather and the altitude of the ambient conditions of manufacture and measurement). In orbit, though, the gumball center has a full atmosphere inside, and a vacuum outside. Thus, it's acting like a pressure vessel, with the pressure inside being like being 30 feet underwater. If the gumball shell is not capable of taking the stresses of this, then the shell will fail, and either simply rupture or pop like popcorn (hence the highly technical term "popcorning"). The Space Shuttle External Tank's anti-ice insulation (which is made up of similar closed cells of foam) would do the same after time in space, which is why no studies for a Skylab-style wet lab were ever really considered seriously--huge risk for orbital debris.

So, if the gumballs aren't strong enough, they pop. How do you know if they are? Engineering! The material stresses on a spherical thin-walled pressure vessel are as below.

Sigma (the o with the line on the left) is the stress on the material. If this exceeds the maximum material properties of un-chewed gumball (chewed gum is over course deformable, which would change things in ways I'm not entirely trained to handle at the moment, but thankfully Space Supply Corp. Inc. Ltd does not supply NASA with ABC gum), the shell will break. In the equations, p is the pressure, so here it's 101 kPA (atmospheric in kiloPascals, the metric unit for pressure). The t is thickness, and the radius is r. Keep these units consistent, and they'll cancel out leaving just a ratio. (For the record, the radius-to-thickness ratio for 1" gumballs is slightly too large for the thin-wall approximation according to rules of thumb. It's 4:1, when 10:1 is supposed to be the max. But you get free engineering secrets for gumball shipment, you take my baseless assumptions.).

Calculating, the material stress is 404 kPa. So...does the gumball pop? Unfortunately, I can't find any research on the material properties of unchewed gum (attention scientists!), but this is a required strength something like 1/2th the minimum strength of rubber, so I feel confident in saying it has a good chance of working. This is nice, it means you don't need to use precious volume inside a pressurized transport like Dragon, Cygnus, CST-100, Soyuz, Progress, whatever, you just ship up your gumballs in a bag in Dragon's trunk, or the HTV external pallet bay, or something like that. You'll need an astronaut to grab it with a robot arm or snag it on an EVA to bring it in, but hey, it works.

SpaceX Dragon Approaching ISS
Unpressurized cargo like gumballs can go inside the cylindrical trunk section.

So, now we have the shipping requirements (unpressurized transport, some minor details on receiving). What's the cost? The current Falcon 9 carries 10.5 tons to orbit, but the version coming with the Merlin 1D upgrade is supposed to increase that to about 16 tons. Both are to cost about $56 million. This is a price of either $5,333 per kg or $3500. Wikipedia says Russia's Proton costs about $4400/kg. I'm not running numbers for the Atlas V or Delta IV, I can tell they will be worse since they cost more than Falcon by a factor of 4 or more for similar base payloads, and the pricing doesn't get better for Heavy versions. Falcon Heavy, on that note, is supposed to get down to $2200/kg.

So, what does this all mean for our gumballs? A 16 lb bag of 1" gumballs on Amazon costs roughly $30 (though the actual specs at the bottom say 17 lbs...odd), and contains 850 balls. Thus, each masses about 8.75 grams. Since the bag comes included in this mass and gumballs are probably vacuum-rated, there's no further shipping mass. So, cost to fly is easy if you completely ignore any cost-sharing or free-rides with other customers: Multiply the per-kg launch cost by the mass in kg of one gumball, and find the cost to user on orbit. For Falcon 9 currently, this would be $46.66, or $30.63 on the Merlin 1D variant that's supposedly coming soon. The Russian Proton workhorse would cost you $37.6 dollars per gumball, while the Space Shuttle is in the range of $291.67 per ball. Falcon Heavy's goal price would see a gumball representing a cost of $19.25. However, while the astronaut is carefully feeding those 77 quarters into the little slot and cranking the handle, note the shipping markup: the cost to Space Supply Corp, Inc, Ltd is only $30 a bag for 850, or about 3.5 cents per gumball, or a shipping and handling markup of about 5400%. For the record, this also means that the 25 cent gumballs you see so often are selling for a retail markup of 200%.

However, the gumball isn't a great metric for spacecraft themselves, just an example of the costs of shipping even a relatively tiny but imaginable payload--this same economics applies to every T-shirt, can of tuna, and bag of wet-wipes sent to the ISS crew and any potential future space exploration. Cheap to supply, expensive to ship. Spacecraft are a bit different, since even a small spacecraft (a bit heavier than a backpack with a few engineering texts in it) might contain several million dollars of specialized components, plus the spreading out of the cost of integration, testing, design and development before selection of a final design....it's easy for me to design something like this costing $10 million that costs no more than $50,000 to launch to orbit where spacecraft cost is only half a percent of total cost. However, any base needs some kind of supplies, and these will include a large portion of the cheap-to-buy, expensive-to-ship variety I mentioned. ISS uses a good amount of food and water, and when HTV-2 burned up on return from the ISS earlier this year, a large part of the trash it carried was foam that had ridden to orbit wrapped around science experiments.

Astrobotic Lander
110 kg of payload to surface available--for a price

As a final exercise for the reader, the Google Lunar X-Prize team Astrobotic has a publicly posted payload planning guide that says a base price of $1.8 million per kg. Find the cost of a gumball delivered to the lunar surface. Highlight for answer: $15,700 or so. A lunar gumball costs about the same as four tons of supply-cost gumballs, 62.8 thousand Earth gumballs, or about 424 orbital gumballs.

Field Reports and Endings

noreply@blogger.com (Rob Davidoff) — Wed, 27 Apr 2011 21:54:00 +0000

Well, it's all over. After about 8 and a half months, the AIAA DBF competition has come and gone. The last few days in Tucson saw a lot of frustration, some sweet tastes of success, and some extremely memorable experiences largely unrelated to competition.

Things got started on Wednesday. The team who were driving our tools and the planes to competition--Kramer, Andrew, and James--left at about 10, while those of us who were flying were not going to leave until Thursday. I was very impressed with their willingness to do this--there's no other way we could have gotten things where we needed them to be, and they stepped up to a task that they knew would mean a drive of around 30 hours each way over 8 states. Then, in the middle of the afternoon, we received the flight order, which is derived from our paper score. To put it simply, we didn't get the kind of score we were expecting. Last year, we were 36th out of about 80 teams with a report score average of 82. This year, we were 67th out of 82 with a field of largely similar teams. It wasn't an auspicious start--we knew our paper was better than last year's in terms of the content. This year the paper saw two more iterations than last year and review not just by Dr. Altman but by some former competition judges and past-year presidents of the club, and though we knew there were things we still could have improved, there wasn't enough wrong to drop the score by the amount 67th would require.

Anyway, on Thursday we flew out to Tucson. I'd been there once before with a school trip, and it was largely as I remember: hot but dry, and scenery that's pretty but kind of dead. We got in around 11:00 local time thanks to a four-hour layover in Denver, and as a result the first thing we did in Tucson was head to sleep. In the morning, we knew that we wouldn't see tech inspection for some time, so while some team members went to the competition site to stake out a spot, others (including me) went to the Boneyard and the Pima museum. Seeing the Boneyard was incredible, all the planes sitting out under the sun with their windows covered and their engines protected to keep them in flyable condition in case they're ever needed. The tour guides made clear the usefulness of this: many of the aircraft in the Boneyard, even the unflyable ones, represent the only source of spares parts or replacement aircraft for not just the USAF, but the air forces of some of our allies around the world. The resulting sight was really other-worldly.

Row after row of old F4 Phantoms--The US doesn't use them anymore, but some of our allies do, so we keep them around for spares and replacement aircraft. Spare part sales help the facility return $11 for every $1 spent.

Note the white sealant around the cockpit windows and other openings. This is to control the temperature inside the plane--keeping it only about 10-15 degrees above the ambient 95 degree weather, as opposed to jumping into ranges like 200 degrees that could hurt the plane. It gave the planes a strange air--I'd never seen anything like it before.

An enormous C-5 Galaxy transport was being processed while we were there--they were removing the engines for storage, and getting the rest of the plane ready for mothballing alongside 18 others being retired as the new C-17 come into service. Incredible to see the scale of these things, even more to see ten or twelve parked under the desert sun.

Some engines being stored in canisters. Made me and several other Star Wars nerds think of the pod-racing scenes from Star Wars: A Phantom Menace. Again, very strange sights.

Across the street from the Boneyard was the Pima Air & Space Museum, which I think may now be among my top 3 favorite aircraft museums--the Smithsonian and the USAF museum here in Dayton have more variety, but the Pima museum was designed in a way that every aircraft could really be appreciated close-up, and the lighting and placement of aircraft both inside the hangers and outside on the grounds made it possible to see these planes in a way you can't at the USAF museum sometimes. They also had an interesting variety of one-offs, including a Super Guppy, which was incredible to get to see. The museum also impressed Dr. Altman, which is not an easy thing to do at all--trust me, I know from experience.

The main hangars were better arranged and lit than the USAF Museum, and though the overall variety wasn't as great, there were some great one-off airplanes.

One of these was the Bumblebee II: A biplane specifically designed for attaining the world record for smallest manned airplane. It had a wingspan barely longer than my arm span, and an incredibly low aspect ratio--maybe 2 or 3? Dr. Altman made some comments about the layout of the wings relative to one another, but I can't recall his specific critique. It was funny to think that this thing didn't have much more wing area than our AIAA plane from last year.

Andrew McClinton (one of two or three members on the team with pilot's licenses) brushes up on his control theory while I look on. This was perhaps not for our precise age group, but Andrew had fun messing with the mobile control surfaces.

I wish I had more pictures of the rest of the exhibit, which was a strange cross between the oneyard and a normal museum, with historic aircraft parked out under the sun where you could wander around between them. After spending about three hours or so at the Pima museum, we left to catch up with the rest of the team at the competition site. Tech inspection this year was in the same order as the flight order, which made some sense, but it was also going rather slowly. At about 1:30 PM when they started letting teams fly missions, which was another change from last year, when we couldn't fly until Saturday. The extra time ended up helping a lot with everyone getting all their flight attempts in, but the early start and the tech rate meant that around 3:00, they hit the end of the 40 teams that had successfully passed tech (about 50 or so teams processed) and looped around so that at the end of the day, while teams 60 and up had yet to even tech, about 20 teams had already had the chance to fly two scoring missions. In the final analysis, it wasn't so bad this year since the weather was pretty good every day, but if weather had been really bad Saturday or Sunday, this could have been very biasing against the lower-ranked teams.

It was nice to have a chance to walk around and talk to the other teams, though. Several people I'd met previously this year or last year were there, including the OSU DBF team (their first year, and they did pretty well with it) and Wyatt and the other USC team members, who shared a hotel with us last year and this year were a lot of help with issues I'm going to be talking about in a bit. Evening activities included a trip to a very good steakhouse, and heading to sleep early to catch up some from the time changes.

Saturday started off with us finally getting a chance to tech, as some other teams were preparing for their second or third flights. Things largely went well--except for the failsafe system. Competition rules require a system on the aircraft's receiver such that if the plane stops receiving instructions from the controller on the ground, it will automatically enter a death spiral. The organizers do this in the name of the safety of the crowd, but it's rather annoying for those teams that see it trip--it means a simple radio issue can send your plane crashing down in a way that may be basically unrecoverable. Failsafes are common in radio-controlled aircraft, but it's more normal to see them set to have the plane slow down to about 50% speed and hold the last command--stay turning, or continue to fly straight or whatever, partly for the same reason: some competition R/C planes can cost upwards of $1000, and pilots don't want to lose them because of radio issues. Thus, most modern receivers and transmitters are actually incapable of performing the particular failsafe required by competition. This included, as it turned out, our receiver--we couldn't get our rudder to deflect properly for the death spiral. Thus, in order to pass tech, we had to spend almost three hours messing around with our control system, and eventually switching to a totally different transmitter/receiver combination, which was lent to us by USC.

Finally, though, we did pass tech inspection, just as they were about to call our number in the flight order's second rotation. We didn't want to miss another chance, so we began packing up the plane, and hurrying to get to the other side of the judging section just as they called our number. Despite calling to them from only a few feet away, the judge proceeded to call no fewer than four more teams--skipping us for another cycle. Combined with the failsafe issue, tempers started to flare a bit. We managed one flight attempt later in the afternoon, on the next cycle, but a poor hand launch didn't give the plane the right velocity for flight, and it acquainted itself with the ground only a few feet away. Though undamaged and still largely ready-to-fly, the impact broke the propeller and repairs were not allowed, so we'd have to wait another cycle to get into the air. We spent the afternoon using a scale and some statics to verify our static thrust, confirming that it was a launch error and not an issue with the climate difference between Dayton and Tucson, then did some more work on the aerodynamics of flying disc-shaped objects. It looked like we might get one more chance to fly Saturday, but we lost out at the last minute. We'd be close to first Sunday, but...seeing two days down, and not a single successful flight brought morale down a lot, especially since we now had only three remaining flight attempts. To fly all three missions, everything had to go right.

By the end of the day, we were all pretty drained and worn down, but this was altered significantly when some friends of Dr. Altman's family invited us to their place up in the hills. The night sky was amazing--the stars and moon were incredibly clear, and the pool and hot tub were a nice change of pace from the heat. For me, the highlight was when we saw a bright object travel across the sky, from the south-west to the north-east. Dr. Altman said it looked like the trajectory for something in orbit, and Alex Hunton (one of the team's new members, and the guy who took so many of the pictures I've been using through here) wondered if it might be the ISS. I pulled up Heaven's Above on my Pre, and the ground track confirmed it; by complete chance, I'd finally seen what I've been trying for months to see, and the sky couldn't have been better for it. For me, this felt like a good sign for the rest of competition, and for the rest of the team, if the space station didn't do it, the excellent food and the pool helped settle some tempers and sooth frustrations.

Sunday felt a bit strange--because they started flights on Friday instead of Saturday morning, the competition was significantly ahead of previous years. Several teams had already completed all their flights, and others had crashed beyond recovery, so the tent felt oddly empty, and the flight rotation was moving through so quickly that the order began to basically fall apart by afternoon and teams were allowed to fly as soon as they were ready instead of waiting on a rotation. For us, though, the day started off very well--we got to the site right at the start, and moved directly into the assembly area to fly. Leslie Sollman once again assembled well within time, even with time to test the control surfaces, then after waiting behind a few other teams at the flight line, Josh took another try at hand-launching for competition. His throw was better, but it still took a demonstration of supreme skill and confidence on Chris' part to recover when the plane tumbled into a roll off the throw, ending up about 15 feet off the ground and rolled so much that one wing was pointed right at the ground. 4 laps and about 3 minutes later, Chris set the plane down in a perfect belly-landing, and we had a score on the board, moving us from 67th place to 43rd. Considering last year we never managed to get on the board, we counted this as a good start, and stopped for some team pictures.

Left to right: Josh, Cody, Dr. Altman, Me, Kramer, Leslie, James, and Alex
Front Row: Andrew and Steven (the plane)

No, Andrew, your other right.

being on the board took the load off of our shoulders--the goal stopped being "get on the board at all" and proceeded to just "do as well as we can." The second mission was the payload flight, carrying a team-selected 3.81 pound weight, with the goal being the highest payload fraction. Once again, though, simply going out and flying the plane eluded us. The weight was preloaded into the plane before normal assembly, and in the process one of the wires from the receiver came loose. If we'd had our normal receiver, maybe we'd have spotted it, but the failsafe issue means we don't know. Leslie once again did a great job assembling the plane, and we tested the flight controls---except for the throttle. Perhaps you can see where this leads?

So, once again, we left the flight line without flying, bearing a plane almost completely flyable...except for one change that would take all of ten seconds to fix. However, this was around the time they switched to "come when you're ready" instead of a roster, and so we decided to take a breath, check the plane once more for any other issues, get good and ready, then go up for our fourth attempt. The videos of assembly and the flight for this one are actually posted, so I'll let them speak for themselves.

Leslie Going to Work

Kramer's Hand Launch and the Flight

The first lap may look nerve-wracking on the tape, when the plane only barely got into a stable flight attitude. Let me assure you that having worked so long on that plane and on getting this far, it was pretty much terrifying. This is Cody's video, but notice the shake? All of us were like that this whole flight. However, Chris did another great flight, and we moved from 43rd, to our final position of 63rd with our payload fraction (percent of total weight that was payload) of 47%--one of the highest at competition, though our 4.3 pound empty weight hurt us on the scoring. My guess is that had we managed to fly our third mission with all 37 golf balls we could carry, we'd have finished at least another ten places higher. Ah well--we finished almost 30 place higher than last year, with two scoring flights instead of none, and concluded a very successful design, construction, and flight testing campaign in which we learned a lot. That's a win in my book.

It's getting to within a week of the end of school, and there's a lot of this kind of wrap-up going on. Classes, DBF, finalizing summer plans, and all kinds of other things. Still, if there's one thing I've learned, it's that as every challenge ends, there's always a new one waiting. Part of me can't wait for school to be over, part of me wishes it wouldn't end for another month, and part of me just can't wait for it to be next year already so we could do this all over again. Anyway, so that's the end of this for another year. More space posts to come as I have the time.

Engineering in Progress goes "Crunch"

noreply@blogger.com (Rob Davidoff) — Mon, 11 Apr 2011 00:48:00 +0000

So, I go on vacation for the weekend, and what does the team decide to do? Play catch with the plane. And fail on the "catch" part.

Click text for video

Thankfully, this is the V1 prototype (a.k.a. The Hulk), and there is a good reason for all this, so I don't need to yell at someone at the meeting tomorrow, which is nice because I don't really like doing yelling. The idea was to prepare for the testing today, since the weather was poor yesterday. To do this, they loaded the plane to an 8.5 pound total weight (2 pounds heavier than any previous attempt) and practiced hand-launching it. Luckily, catching the plane is not required at competition.

Today saw six hours at the field, and about 10 flights to apply payload testing to the competition aircraft and verify the stuff needed for the Pre-Tech Certification paperwork. I'll put edit some links and more detail in as I know them. Regardless, it feels like we're really ready for competition, and I'm really looking forward to getting to talk to everyone at Tucson. Competition was great last year; getting to hear others talking about solving the same problems our team did in different ways and with subtly different assumptions leading to radically different solutions was very enriching, and I think it helped with our process this year. This year, having been much more involved with the process of design and having the experience of building three different airframes, I think it'll be all the more interesting.

Actually, I know it will for me, I had a taste of it last weekend. At the AIAA Region III Student Conference, I got to talk to some members of The Ohio State team. This is their first year, and they sounded a lot like they were in the same position we were last year in terms of team-building, but their plane still was interesting enough in its approach that I found discussing their approach and comparing ours to be very enriching.

Big Rockets and a New Launch Site (For Real)

noreply@blogger.com (Rob Davidoff) — Tue, 05 Apr 2011 18:52:00 +0000

So, the SpaceX announcement of their new "something big" happened earlier today. It's not quite what I joked about yesterday, but it's still very impressive. In many respects, it's much of what was predicted: Falcon Heavy official announcement, a new launch site at Vandenberg capable of launching the Heavy, and modifications to their launch site at Cape Canaveral to be able to launch the Heavy there too (the current integration building is not large enough for the three-core Heavy). However, as always, the devil is in the details, and in this case, those details are perhaps even more impressive.

The big deal started with the timeline: the Vandenberg site is supposed to be in condition to take delivery of the first Falcon Heavy test flight components in November or December of next year, with the launch actually occurring in 2013. They're starting construction very soon, but even with that it's an aggressive schedule. I'm not sure when the modifications to their Cape Canaveral pad will begin, but the design they show is interesting: the new integration facility for Falcon Heavy will be at 90 degrees from the current building, allowing construction of it to take place without requiring interruption of their manifested launches to the ISS or other commercial flights.

However, the impressive details continued with the specifications of the rocket. The Falcon Heavy as announced will use the Merlin 1D upgrade on the first stage over the currently-in-use Merlin 1C, with corresponding thrust and payload increases. Additionally, the rocket is to use what's known as cross-feed, where fuel from the side cores (see above) feed the engines on the middle core until the staging event where the side cores separate. Thus, after staging, the end result is essentially a nearly-fully-fueled Falcon 9 rocket, already going very fast and already very high. Cross-feed adds complexity, but it's not impossible--similar technology is used to feed fuel from the Space Shuttle External Tank to the engines mounted on the Orbiter. And the benefits of all these modifications? Musk today cited a payload capacity of 52 metric tons--more than any other current launcher unless you count the mass of the Space Shuttle vehicle as payload on the Space Shuttle stack as opposed to the 30 tons or so of payload in crew and cargo (which is a somewhat contentious assertion, but I'll say I think it's fairly valid). These assertions and more are detailed on the updated Falcon Heavy section of the SpaceX site, and the video here.

Click here or image for SpaceX promotional video

This 53 ton figure was quite unexpected--up until today, the SpaceX site had been listing a figure of only 32 tons. I suspect that cross-feed and Merlin 1D has a lot to do with that, but it'll still be interesting to see if they can match those figures in practice. The launch rate and associated price figures they cited are also interesting. Apparently, they hope to launch up to 20 vehicles a year, half Heavies, half Falcon 9. That's a tall order, and I'm not sure if I buy it completely--SpaceX has something of a record of predicting more than they can handle, and it's such a change from the current levels that they're operating at that I'm a little skeptical. I would love to be proved wrong--the payload cost numbers they cite for those operating levels are incredible, enough that the cost of launching a 1 kilogram CubeSat would be something someone like me could almost pay out of pocket in cash, but...it's a big step from two launches a year. Impossible? No, but still hard.

The other people that want more proof, I think, are the Department of Defense. Part of this push for a pad at Vandenberg and the Falcon Heavy is to try and play for DoD business, like Atlas V and Delta IV currently do so, and the numbers SpaceX cites are extremely competitive if they are at all close to the achieved prices--the quoted price for a Falcon Heavy on the SpaceX is something like a quarter of the cost of the Delta IV Heavy, while Falcon Heavy will apparently be much more capable. Again, grain of salt with all of this, but SpaceX is playing hard for things, including releases like this one now on their site which includes the below as a conclusion:

I have no doubt that the Falcon Heavy vehicle unveiled today is technically feasible (in that it could be built and flown, with enough time and money--though by those standards, Ares I was technically feasible), and I'm willing to give SpaceX the benefit of the doubt with their payload values and even their cost figures, given the assumptions they state in terms of technical upgrades and flight rates. I'm not sure if I'm convinced SpaceX can put those dreams into practice, but one thing I love about SpaceX is that they're going to try. ULA has had some really interesting ideas for years--the ACES upper stage, further EELV evolutions with Phase 1 and 2, and yet...where SpaceX is indicating a willingness to push on ahead of NASA or the current "conventional" market in the hopes of finding new markets and new value made possible with new techniques, ULA has not done so, even though they have a number of people in-house and out here in the interested observers area convinced their plans are just as viable as what SpaceX proposed today. The difference is that SpaceX is actually doing them.

It'll be very interesting to watch this all play out, and I'm more excited than ever to get done with my degree and actually get out into the field proper--it feels like everything's changing. Some for the worse, maybe, with NASA's recent direction-less drifting and the end of the Shuttle, but possibly in other areas of the field for the better. As if one big piece of news in a week wasn't enough, by the way, there are rumors that the Commercial Crew Development 2 announcements are coming soon, which should also be very interesting. Who knows, maybe you all will get lucky and I won't find time this week to bore you with my Aerodesign Team pictures and videos between all the space stuff?

SpaceX Announcement Leak: Big Rockets and a new Launch Site

noreply@blogger.com (Rob Davidoff) — Mon, 04 Apr 2011 17:08:00 +0000

EDIT: The below was posted as my April Fool's joke, a little late. If you're arriving from Google or elsewhere and were hoping for serious updates on the SpaceX Falcon Heavy announcement, try this post instead for my serious reaction to the actual news.

So, there's been a lot of chatter the past week or so about the teaser video SpaceX put out, linked below.

That some element of the Falcon 9 Heavy (now apparently renamed Falcon Heavy, possibly because of the planned switch to a single Merlin 2 engine per core instead of 9 Merlin 1Cs sometime in the future) was going to be announced, and that a new launch site might be involved was also not unexpected (plans for a site at Vandenberg capable of processing the Falcon Heavy have been filed with EPA already, several months ago). However, new leaks (I can't cite sources yet) indicate that this may not be the entire extent of the "something big" coming!
New source inside SpaceX suggest that the Vandenberg facility is not the only new launch site SpaceX has been working on, nor is Falcon Heavy the only rocket being announced. In fact, SpaceX is planning to announce their new Thunderbird rocket, which is the implementation of their Falcon X and Falcon XX proposals. The cores for Thunderbird are in fact too large to be road-transported as Falcon is, so the new rockets will have to be built and launched from the same site. To this end, SpaceX has been constructing an underground Thunderbird construction, integration, and launch facility beneath Mr.Musk's personal island residence for several months, and the Falcon Heavy is to be the first vehicle to use it, with launch NET April 5, 2011. A leaked image of a model of the new site is depicted below, showing a generic rocket (SpaceX plans to offer the site to other users during periods of non-total use.) on the launch stand, with the launch site's water damping system and weather cover yet to retract to the launch position.

Of particular interest is the switch from horizontal integration as they are using at the Cape and the Vandenberg site filings to a vertical integration technique at the Musk Island site. This could be an indication that they plan to try for more manned launches, or increased competition with other launch providers like Arianespace who integrate vertically (payloads would thus not require redesign to be fitted onto Falcons or Thunderbirds launched from Musk Island). I meant to post this a few days ago, when more time remained before the launch, but I'll wait for the full announcement tomorrow with baited breath, and my best to the team preparing Falcon Heavy for its maiden flight, and the Thunderbird 1 vehicle for next Tuesday. FAB, guys.

At Long Last

noreply@blogger.com (Rob Davidoff) — Tue, 29 Mar 2011 13:54:00 +0000

Finally, Josh got around to buying the cable he needed to upload all our flight videos, so in a moment that I'm sure will have all of you out there on the edge of your seat, here's the flight videos for the UD AIAA DBF team 2010-2011 season so far. First off, videos from the second round of flights with the prototype on March 20th.

Click Here for Flight 1 Video

Click Here for Flight 2 Video

On March 20th, the prototype made two flights, first with a payload of 1.0 lbs, then with a payload of only 0.5 lbs. These was intended to be empty flights, but some tail-heaviness left us in need of nose weight. In fact, on the 0.5 lbs second flight, the reduction in weight left the aircraft very pitchy in flight. However, the propulsion system was finally reaching a configuration that was a bit more in line with the power and duration that we'll need at Tuscon.

Anyway, so that was a week ago. In the past week, we completed and flew V2, our second aircraft. V2 is almost a pound lighter than the prototype (a 20% weight reduction) and reductions in the tail mean that it doesn't have any of the CG issues which plagued the prototype. We managed two flights on Sunday despite the cold on the field. It may look sunny in the videos that follow. It was sunny, but still cold, to the degree that our flight duration on the second flight was constrained not by the plane but by the pilot's fingers getting too cold to keep flying.

Click Here for Video

For the first flight (video link above), we flew empty, the first properly empty flight we've been able to do all year, thanks to the reductions in weight fixing our CG issues with the prototype. Our normal plane-chucker Kramer Doyle wasn't present, so Josh filled in. On its maiden voyage, V2 did incredibly well--good launch, fast as heck, and no hint of the pitch issues that plagued the prototype. Additionally, we discovered that when in the air, the pinkish wings don't look quite so bad--distance and motion blur cures all wounds, apparently.

Josh with V2, Second Flight. Click this Text for Video

Our second flight of the day was a 2.0 lb payload flight--exceeding our original design goal by almost 0.5 lbs. However, even with this, the weight reductions on V2 meant we were still 0.5 lbs below the maximum flight weight from the prototype. Obviously, we had a bit more drama getting into the air this time--as noted, Josh is not our main thrower, and his co-ordination with Chris wasn't quite perfect. However, the result is impressive. This flight had a 35% payload fraction, and if we load the plane to our maximum demonstrated gross weight from the prototype, we'd have gotten a payload fraction of 42%--well in excess of what we were hoping for during the design face. Originally, the fuselage was designed with enough room for about 50% more golf balls than we were designing the wings to lift, for a few reasons too boring to go into. However, it now looks like not only will we fill that volume, but we might have the capability to lift a few more than that!

In the next week, we're going to be putting together the final competition plane, V3. Again, the construction of a third airframe is new to the team's history, and I'm looking forward to further weight trimming. We should also be able to clean up our wing and tail layups a little and get rid of some of the wrinkles we ran into on V2's wings. I have high hopes for V3, and I'm really looking forward to competition.

Long Hours

noreply@blogger.com (Rob Davidoff) — Sun, 27 Mar 2011 05:49:00 +0000

This post may not be up to my usual standards, it's very late and I'm tired, but I had a few things I wanted to show off. I spent almost every waking hour today in the wind tunnel, working on something that to my knowledge is unique in the past five years of the UD Aerodesign Team--a second aircraft. After a long week of work, we finally have it flyable, and I have to go to bed soon so I can get up in the morning and go to the field, but I wanted to share some images I took today.

UD Aerodesign Team aircraft, awaiting transport to the field tomorrow

In the image above, the prototype that I showed images of last week is on the right in pieces, ready be packed for transport to the field. The new plane (called V2 because we've been too busy to be creative about names) is assembled on the right. V2 incorporates several lessons learned in the construction of the prototype, and its very existence is owed to some new techniques we've been practicing this year.

The most critical new technique is the fuselage molding, which we've been doing with assistance in the form of advice and facilities from Industrial Fiberglass Specialties here in Datyon. I talked in my last post here on Engineer in Progress about what a difference this makes in terms of the time and materials, and the plane above is the payoff. Thanks to more experience with the techniques involved in making fuselages from the mold, the new fuselage weighs almost half a pound less than the original, yet still incorporates several structural modifications to reinforce areas that the prototype demonstrated weaknesses in. Making new fuselages is in fact so easy that the fuselage team went ahead and started work on laying up a third fuselage, which will probably be combined with other componetns we have around to produce a third (!) aircraft to our design, with further refinements from the flights and construction of V2.

The really tricky part of V2 was the wings and tail. Normally, we hot-wire cut the wing and tailplane foam cores on a CNC foam-cutter, enabling great accuracy and precise adherence to our designs. However, the construction of V2 was hampered by the fact that the foam-cuter broke between the cutting of wings for V1 and the cutting of wings for V2, requiring that the surfaces instead be hand cut with a wire bow. Josh Nieman, the club president, spent over six hours working to produce the wings and tails for V2, going through an entire 4 foot by 8 foot sheet of 2-inch insulation board in the process. The resulting wings, while not quite up to our normal standards, are still very good, and the implementation of some suggestions from Greg at Industrial Fiberglass enabled us to trim 17% off the weight of the wings by reducing excess epoxy used in our layup--this is demonstrated vividly in the different color of V2's wings compared to V1 as seen below:

Prototype is at the top of the image, V2 at the bottom

V2's wings and tail were laid up using epoxy with the same dye concentration as the prototype. The pinkish tint of V2's wings and the increased visibility of its carbon-fiber reinforcement is due entirely to the reduction in the total amount of epoxy on the wing. The imperfections of the wing are not visible from this angle and distance--the trailing edges are a bit wonky due to cutting difficulties. However, the wings for V3 (which should end up being the competition plane) will be CNC-cut as like the prototype wings were, and thus should have all the improvements of V2's techniques implemented with precision cores like the protoype used.

The testing of new techniques to see what works like with the fuselage and the wings is something we didn't have a chance to do last year, since we only had one plane and one set of wings, and making full use of this ability throughout the plane should make our team more competitive at Tuscon--I know I feel that V2 is a better plane on the whole than the prototype so far. Tomorrow, we find out for sure when V2 (hopefully) makes its first flight attempts, which means for now it's time to get some shut-eye.

Aerodesign Update

noreply@blogger.com (Rob Davidoff) — Tue, 22 Mar 2011 01:19:00 +0000

I'll admit, I've been putting off posting about the AIAA team. Not because of a lack of things to talk about, but because I've been having trouble laying hands on things to show. Since the last time I posted, the prototype has had about six flights, of varying degrees of success, and we've started working on our follow-up competition aircraft incorporating lessons learned making the prototype. However, video or images of those flights are not on the web yet, except for the rather pathetic maiden flight.

Click Here for Video Link

As Josh notes, the crash was not as bad as it looks, and the plane was flyable again after an hour or two of work. A little experimenting with motors and propellers found a combination that produced power more like we'd been anticipating, and the current setup is much faster and much better in the air. However, as I dais, I don't have any images or video of that I can point to yet. It's been a long time since I did a proper update, so in place of flight highlights, I'm going to post some images of what, in general, we've been up to. More awaits below the cut.

The prototype, nearing completion. Much prettier than last year's plane (TOM) if I do say so myself.

This year's plane differs in a number of ways from last year. First, after last year, there's a larger core team who generally know how to do what needs to be done. Our president, Josh Nieman, has really taken that core and pushed us to put those abilities to the best use possible, and it payed off: we flew before the paper was due, and incorporated some flight data into the paper, compared to last year when we flew about two months after the paper due date. Thanks to that, we're now able to spend the next month or so remaining before competition fine-tuning our configuration and building the competition plane, instead of desperately working to get one flyable plane.

Another change from last year is our use this year of a molded fuselage, rather than a built up fuselage. What that means is that previously, our fuselage was built from discrete panels of carbon-fiber honeycomb, connected at the joints with carbon fiber strips. This required very complex build-ups, and was costly in terms of time and materials. An image of this process in action can be seen below--yes, this was infact every clamp in the shop in use at once.

First, we would build up the sides.

We would bend the skin-hinges to shape the front and back of the fuselage.

Finally, we would add internal bulkheads and other structure.

Overall, a very complex process. Note the couch in the background of the last picture. This couch was just as terrible as it looks, but it had over the years been beaten to the exact right level of comfort. I used to read on it while waiting for epoxy to dry. It was comfortable, but now it is gone due to safety rule changes. I miss it a lot. Regardless, the new process is a lot different. Instead of building up from panels, we're making use of a negative molding process with the assistance of Industrial Fiberglass Specialties (who have provided the facilities and equipment required). To start, we make a core in the shape of the part we want to make. This core has to be just right, so it took us about three tries to get one right this year. I participated in the preparation of all three cores.

First core. Pretty, but unfortunately the wrong airfoil on the root section

Second core. Produced in only about 10 hours. Correct wing section, but not pretty--didn't go together right.

Me with the third and final fuselage mold core after layup and waxing

Next, we used this fuselage core to build up two molds for the fuselage. One makes the top of the fuselage, the other makes the bottom. Once this mold is made, we can make as many fuselages as we care to with only a few days work by laying new fiberglass into the molds. This is a large part of how we're making two planes this year when last year we were only able to make one. The molding technique reduces the time, effort, and cost of additional fuselages which in the old technique were the most effort and cost intensive element.

We also completed the connections on the plane. If you'll recall, a few moths ago I a diagram that showed the types of connections the plane was planned to use. If you don't, here's that post linked, and the diagram in question is reproduced below.

Connections used on aircraft

It's interesting (to me anyway, and this is my blog, so that's what matters) to compare this to an image I took a few weeks ago of the plane disassembled to move to the testing field.

Aircraft disassembled in preparation for packing

Other than the landing gear, you'll note that the plane above very much resembles the diagram above. I'm very proud of how the connections have moved from concept, to design, to execution this year without severe changes. Minor tweaks have been made to materials and some geometry, but the concept and designs are largely reflected in the aircraft as built, which is much more than I can say about last year's aircraft.

On the theme of dramatic images, some more from testing the connections. I made a test version of the wing spar connections before the prototype was built, and tested how well it stood up to shear and moment loads by cantilevering it over the edge of a workbench with weights on it. The image below shows the connection taking 24 pounds of shear load, and a applied moment of 12 pound-feet, equal to our plane in a 5 g turn with margin. As you can see clearly, the connections had no issues with even this overload.

We also added the wing locking connection recently. These wing locks prevent the wing from pulling off of the fuselage along the axis of the spar and alignment pins. In flight, these forces along the wing (known as "spanwise forces" in jargon) are fairly minimal, however, the connections we've designed are capable of taking fairly significant forces without issue, as demonstrated below.

Should have seen the one that got away....

In this image, the entire weight of the fuselage, batteries, motor, and the other wing are being applied to the port wing locks without issue. This ensures we have plenty of margin, and gives us a lot of resilience to damage. The overall size of the plane is also fairly visible in this image. I stand 6 feet, so you can get an idea of what a job we're doing getting these wings to fit into a conventional carry-on suitcase. We do it, though.

I'd love to close this piece with a flight video from one of the two more recent times at the field, with the plane cruising around like a champ, but as I mentioned, I don't think they're on the web yet and I don't have the files to upload myself. Instead, I'm going to point to several videos from last year showing our biplane from three years ago doing flips with the hugely over-sized motor from last year's plane.

Missed Chances, Pretty Pictures

noreply@blogger.com (Rob Davidoff) — Thu, 17 Mar 2011 23:58:00 +0000

Well, the STS-133 flyabout I (and many others) were looking forward to didn't happen. From what I understand, the concept was handed to the Russians for their analysis too close to the mission, and since this was the first flight of a new Soyuz variant, they didn't feel comfortable going forward with the flyabout. It's regrettable that we missed out on the images, but I think the Russians made the right call.

Still, this was a truly historic occasion, even if there were no images. The station had spacecraft on-orbit at the same time from every one of the station partners: NASA's Shuttle, Russian Soyuz and Progress vehicles, the European ATV, and the Japanese HTV. Thus, several people have taken it upon themselves to make sure this station configuration will be remembered. There's so far been one or two great composited images, adding Discovery digitally to the images Discovery took of the station in her own fly-around, but I'm perhaps most impressed by the series of images posted in this thread on NSF. I'm reposting them here only so more people might see them. They are not my work, I'm simply so blown away by the work Keith did I that I want more people to see them. More of Keith's work can be found on his website.

If you recall a post last year when I talked about how long the ISS has taken to finish? Well, the US orbital section (which is a strange name, since it's majority European-built by volume and also includes significant Japanese portions with the Kibo lab) is finally done, leaving the station with only Russian components still left to go up. Even with that left to do, it's pretty impressive:

Taking Stock

noreply@blogger.com (Rob Davidoff) — Wed, 09 Mar 2011 20:03:00 +0000

So, I'm trying to get a better hold on the events of the past few weeks and what it means for this blog. I started Engineer in Progress mostly to serve as a way to put my thoughts on space and my work on the University of Dayton AIAA Design, Build, Fly team on the web in a place where friends, family, and perhaps someday potential employers might see it. Until February, that was basically what was happening. I'd see a few hits a day, mostly people coming to the blog from Google Images.

However, as I've said, in February I saw over 800 hits between links to several of my posts from Winchell Chung's twitter feed and a third party linking to my Only a Model post on NASAspaceflight's forums. Already so far in May I've seen more hits than I did in the entirety of December, and I posted four times then compared to so far none this month. I was fine saying whatever I wanted to an echo chamber, but saying the same to an audience that I don't know but know is out there is a bit more intimidating. I'd like to continue posting updates about UD's AIAA team, I've got some posts about some aerospace ideas that have been percolating, but I'd like to know my audience a bit better.

So, basically, if you've liked what you've seen here on Engineer in Progress, if you're interested in helping me continue to improve this blog, I'd love to hear from you. There's a comments section down below and my email address is now under the "About Me" link in the sidebar. Let me know what posts you've enjoyed or found interesting, others you haven't, and any suggestions for improvement would be appreciated. Thanks for your time, and I'm sorry this post kind of sounds like a PBS pledge drive. Regrettably, I can't offer tote bags or Carl Kassel's voice on your home answering machine, only more posts as compensation for your support. I hope you'll take the time to let me know what you think anyway.

And now for something completely different...

noreply@blogger.com (Rob Davidoff) — Mon, 28 Feb 2011 01:39:00 +0000

Well, I'm completely floored. No, that's not just exhaustion from AIAA talking, the plane flew and the paper is now submitted, so I'll have more to say here now that my time isn't being puled six ways, I'm down to about four. What's got me picking my jaw off the floor is that over the last three days, I've seen more than 320 hits, all thanks to a link to It's Only a Model from the NASAspaceflight forums. Not only is this more traffic than I normally see in a month, but it lead to something very, very cool.

On Friday, I got an email from a guy at Bigelow who'd followed the link. He said he appreciated my kind words about the company, and that he'd pass along my post to the model guys at Bigelow on Monday. It's still incredible to think about. Hopefully, I'll have a follow-up in a few days as to whether or not my calculations and guesses were correct. Even if I was wrong, better understanding what Bigelow's display models really are claiming would be good data to help me revise my Transhab Module Calculator, which was the point of the analysis that lead me to write that post in the first place.

Internships are the next major hurdle on the road for me. I've been applying to scholarships and internships for a while, and the deadlines are starting to get close. Hopefully, this summer won't be a repeat of last summer, where not only was I unable to find internships due to a late start, but I spent all summer unsuccessfully trying to even find a job in Cincinnati (with the move from Indy, working at my old pizza-prep job in Indy would have been....a heck of a commute). I can't say it didn't pay of, it was because of the spare time that I was able to do much of the fundraising I did for the Aero Team for this season and that I stumbled across NSF, but...I'm hoping this summer I'll be able to find something that's a little better at showing off my talents and abilities. It's got a me feeling a little under stress, anyway, in addition to continued flight testing of the plane, and classes and everything else.

Wings 'n Things

noreply@blogger.com (Rob Davidoff) — Tue, 15 Feb 2011 04:56:00 +0000

So, if you've been wondering where I vanished to the last couple days, here's the answer: AIAA DBF. I've got a post about the Liberty rocket percolating, and the second ATV is on the pad for a a launch tomorrow at 4 PM (ish) EST, and STS 133 is enjoying a smooth flow, and that's all out there in my mind, but what's been in the front of my mind the last few days has been more atmospheric.

Insufficient Lift for Current Payload--Please Try Again

We've been busily working towards getting our prototype airworthy before the paper deadline, with a flight date set for this weekend so we can get the data into the paper. It's been a bit of a rough ride, characterized by late nights, delays from shipping issues, but I think that the effort shows--even if we miss our goal of getting the plane flight data in the paper, which I think is not an unreasonable goal at this point, we'll still be way ahead of last year, and I think with a much more solid design.

Still, this is a time of the year I both love and hate. I love seeing the plane come together after all the work, and I don't mind the time investment and dedication required to do so. However, this is the time of the year that really tries my time-management abilities, and where I have to remind myself that while I love Aerodesign Team and the feeling of working on real problems, I'm not a full engineer. I'm still a student, an engineer in progress, and I even if the plane needs my time, I still have to be able to get my homework done and wake up in the mornings.

My link tonight is last year's first flight video. Note the date, and compare that we may fly this weekend if all goes well--seven weeks earlier even with the loss of time from the month-long holiday break. We'll be checking the landing gear bolts more carefully this time, too. With any luck, I'll be able to point a link towards some images of the wings from above putting a new plane in the air in a week or so--I guess I make a poor power source, so we'll stick to batteries and electric motors.

Flying the Future

noreply@blogger.com (Rob Davidoff) — Tue, 08 Feb 2011 15:09:00 +0000

These days, it seems like I can't wait to wake up in the mornings and read all the latest commercial space news. The last week has seen announcements about Bigelow's plant expansion, SpaceX has released a couple of interesting tidbits I'd like to talk about, and one of my least favorite rocket designs (Ares I) may be coming back from the dead in a new guise but up to the same old tricks.

I talked about the Bigelow stuff a few days ago, but that was closely followed by several interesting pieces of news out of SpaceX. The first was a release from the EPA approving (at least from the environmental end) SpaceX plans to take over SLC4E at Vandenberg and convert if to flying Falcon 9 and Falcon 9 Heavy at a combined launch rate of up to 10 launches a year. I'm not sure I buy that capability, but they are proposing an integration facility large enough to handle the Heavy version (about 3x the floor space of the facility at the Cape, which is good: the Cape's building I think will become an issue if/when they try to start F9H ops there). SpaceX took about 2 years from handover of LC40 at the Cape to operational status, taking over the complex in 2007, starting work on conversion in April 2008, and erecting Falcon 9 on the pad there for the first time in January 2009.

In addition to plans for a new launch complex, SpaceX also announced that they've signed a deal with the Google Lunar X-prize team Astrobotic Technology. Astrobotic now has reserved a launch of Falcon 9 NET (No Earlier Than) December 2013 for their first flight of their lunar lander. Falcon's not the best launch vehicle for lunar operations: with the current second stage, it maxes out at about 2 metric tons pushed through lunar orbit injection, which happens to exactly fit the Astrobotic proposal. However, Falcon 9 gets that performance at a price point that's hard to argue with.

I'm probably running the risk of being dubbed a Kool-aid drinker, but I really do like what SpaceX is doing. Falcon 9 and Falcon 9 Heavy (if they ever finish it) seem like great rockets, and the company's facilities seem capable of handling them at a good rate. Elon was recently quoted as saying they're currently building a Falcon 9 every three months or so (about 4 a year), and that by 2012 they hope to have that down to six weeks (for about 8/year). So far, they seem to have a manifest that means they have the clients to fly Falcon 9 as often as they can build them, between COTS/CRS flights for NASA, Orbcomm satellite launches, and various other manifested flights. Their model isn't perfect: they certain;ly still need some work on stage recovery if they hope to get that down, and if they want to reach a construction rate capable of supporting their hoped launch rate, they may need a second facility or something, but it's quite far for a company founded only eight years ago to now be poised to be one of the dominant players in the US commercial launch market, and perhaps even the international one.

However, at leas this morning, my excitement over SpaceX is tempered by some unpleasant news in my AIAA morning newsletter. I've never been a fan of the Ares I: I'm not a fan of big solid boosters, but I do acknowledge that they provide critical T/W during the first few minutes of the profiles of the vehicles that use them. However, this is only true when fired in parallel with a liquid stage (or stages) that then do the actual work of getting to orbit. The Ares proposal of using a single one of these giant solids as a first stage....well, it worries me. I don't think it's easy, I don't think it'd be cheap, and the crew escape position is very tricky because of the high thrust of the solid-only first stage. So, now that ATK's finally having to face the fact that Ares I is dead with NASA at this point (though they may still get 5-segment boosters on a SDHLV), they've apparently teamed up with Astrium (who do the Ariane V core stage) to produce a new "Liberty" luncher vehicle for the second round of the NASA commercial crew program. The NYtimes, WSJ, and others are carrying the story, though I'm personally waiting for the article from Chris Bergin at Nasaspaceflight.com, since though it's not yet available as I write this post he's promising to take a look at the technical details of it instead of just spouting numbers from ATK's press release.

I'm not sure I can put into words why I don't like this plan other than that I feel that the Ares I program was an unneccesary program to develop a crew-launch capability that could have far more easily, quickly, and cheaply been achieved on a man-rated Atlas V, Delta IV, or something like that (possibly already could have been flying by now for probably less than half the cost of what work has been done on Ares I), and the 5-segment solid first stage....honestly, it scares me. However, with the Liberty, ATK will now be playing in the same arena as SpaceX's Falcon 9 and F9H, the ULA Atlas and Delta, and international vehicles like Ariane V and Proton in a realm where cost and performance are everything, and I think the true capabilities of this rocket will rapidly become apparent, and that the reaction in the marketplace will be appropriate to that. Personally, I'm not expecting great things. Not to mention the important fact that CCDEV2 is a spacecraft program, not an LV program...we'll see.

On a more positive note, the UD Aerodesign plane is beginning to come together. The fuselage is in the process of being molded after the completion of the core mold at about 11:40 PM last night (I'm sorry, sleep? What is "sleep"?) and the wings should be cut tonight. We're now looking at a tentative first flight on the 19th if we can keep the schedule, with a fall back date the next week if the schedule slips. Even if we have to slip to the 26th, that's still enough to allow us to have some flight test data in the paper, and that would make this one of the first times in Aerodesign's recent past that flight was achieved within the paper deadline. I'd like to show of some images (I'm a bit like a proud parent that way), but I think I'll hold off until the paper deadline, or until we fly, then show it all at once so I don't feel like I'm giving too much away.

Inflatable Company for Inflatable Modules

noreply@blogger.com (Rob Davidoff) — Sat, 05 Feb 2011 06:50:00 +0000

Since the top traffic items on this blog (as I see in the stats) are images of the BA 2100 I posted a while back, I think that talking about further Bigelow news wouldn't go unwarranted. Last night, the local Las Vegas news ran a story about Bigelow's production facility expansion. The building should be operating next year, and it's a 185,000 square foot production plant for inflatable modules. It's not for R&D, it's not for testing, it's to build space hardware on three lines. Today, NASA Deputy Administrator toured the current facility, and out of her tour came some images of the inside of mock ups of some of Bigelow's habitats. I'm not sure which, because BA330 and Sundancer differ mainly in length, but it's an interesting view--very apparent how much larger these modules are. While there, she apparently discussed some elements of a rumored deal to add a Bigelow module of some sort to the ISS, which is supposed to have a contract ready in about 3 months and hardware on orbit 24 months after that.

NASA Deputy Admin Lori Garver inside Bigelow mockup

In addition to the facility expansion, the company also plans to add 1500 new jobs (increasing in size by a factor of ten) over the next 3 years, with about 1,100 just in the next year as the new plant comes on line. Considering the potential of what they're doing there, I'm certainly wondering if they'd have room for an intern or junior engineer. Even if they don't, the possibility of commercial spaceflight is becoming more real with every success like this, from SpaceX's Falcon and Dragon to Bigelow's previous and ongoing successes in station modules, to the work of companies like Armadillo and Virgin Galactic in various areas of suborbital research. Even old space hands like Boeing are getting into the act. With NASA's future still more than a little murky, it's reassuring and perhaps even exciting to see that the state-of-the-art isn't waiting for NASA this time.

In other space news (what was my top space news until I heard this), NASA's looking at undocking a Progress vehicle during the STS-133 flight (which is at the pad and on-schedule for Feb 24th) to get some images of all the ISS access vehicle docked at once in sort of a "family portrait" of ISS, Shuttle, ATV, HTV, Soyuz, and Progress. They did something similar during Mir for the famous image below, and I know that I'm not the only one that would love to see something similar for ISS.

In things a little closer to Earth, the AIAA DBF plane is coming along on schedule. We put together a prototype of the wing connections, and the real wings are only a few days away from being cut, so that's coming along. The fuselage is being troublesome, but I feel confident we'll get it nailed down on time. Even if we don't we're still well ahead of where we were last year at this time, and I feel confident both that the plane will come together and that when we take it to competition, we'll do well.