Wednesday, June 29, 2011

Free Time? What Free Time?

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)

Tuesday, June 14, 2011

Good News and Bad News

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.

Wednesday, June 8, 2011

Imagined Images and Reality

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 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.