Author Topic: Mars Challenger  (Read 1982 times)

Offline aftercolumbia

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Mars Challenger
« on: 02/26/2007 09:40 PM »
online at http://aftercolumbia.tripod.com/id14.html (direct link to PDF file is not possible...also turn on you're pop-up blocker...yes I know Tripod sucks, but I'm too lazy to change it.)

Mars Challenger is After Columbia's entry into the MarsDrive Consortium's sample return mission contest.  It attempts a new tactic to combat the desired payload vs. landing capabilty problems we're having on Mars.  Here's a brief on those:

http://www.ssdl.gatech.edu/Papers/Technical%20Papers/IEEE%20Paper%2006%20ID0076%20FINAL.pdf

Mars Challenger selected a reverse contamination protection strategy called Astrobiological Sample Qualification (ASQ).  I'm certain that this is the best way to protect Earth: make sure there isn't harmful life in the returned samples.  That leads to a heavy scientific payload...one which is temperature and vibration sensitive.  For the ISRU (In Situ Resource Utilization) fuel plant making the fuel for the return trip, you have two compressors, compressed carbon dioxide, hydrogen, methane, oxygen, etc. in various states, lots of different temperatures and vibrations, it might be a pain to put the ASQ payload on the same lander.

The punchline is to put the ASQ payload on the rover which goes and collects the samples, and dedicate the lander that carries the booster to ISRU and booster launch.  Each payload has its own lander for arriving at Mars, but both launch to Mars using a single booster and cruise stage.

Grant Bonin, when he wrote Mars For Less, understood the main problem of sending people to Mars as being the heavy lift booster, so he proposed stringing upper stages on Earth LEO like rail cars and combining them for the TMI maneuver.

It's a solution for the wrong problem; the problem is landing big payloads on Mars.  I haven't got it in "technical paper" form (yet), but my latest idea for landing people to combine smaller landers with surface autonomy, I call it "Mars For Way Less."  I don't know yet what size of lander is ideal, but that is something we can kibbitz on.

As for Mars Challenger, even though it splits its payload among two landers, the larger of the landers (the one for the return booster and associated fuel plant) is actually larger than the one for Mars Science Laboratory.  I'm pretty sure it will work within the Viking qualification levels because it is lighter than Science Laboratory, and uses a ballistic entry.  The reason it is larger is because the booster tanks have either liquid hydrogen or nothing in them (helium pressurant notwithstanding) resulting in one of the fluffiest landers imaginable.  Also, the backshell wall angle is a bit lower than for Soyuz, so I'm pretty sure I can get it QBS'd (Qualified By Similarity, also known as "heritage".)

QBS is what you want to do when you have no money...testing is the expensive part.  The problem is that it has to be really close to something where the money has been spent for testing, and some analysis (cheaper than testing but still expensive) may need to be done as well.  QBS means its not new technology...dang.  It's interesting to see how the parachutes and aeroshells of all Mars landers draw to Viking, but they try different touchdown techniques every time...airbags, off-pulsed engines, and hover crane, because it's easier to test if you stick to the endzone.  Chinook helicopters (while still being expensive) are cheaper than X-15s for testing these sorts of things in flight (probly part of the problem is that we don't have X-15s anymore.)

Anyway, closer to topic.  I got Mars Challenger in the open now, so I'm wondering if there were any fellow MarsDrive competitors, or anyone else interested in such things.

Offline KNebergall

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RE: Mars Challenger
« Reply #1 on: 03/11/2007 12:52 AM »
Hello!

I'm one of your competitors.  While I made the submission deadline, I barely did so and send in something that needs a bit more proofreading.  I'll eventually make my work visible as well.  You can find my Earth Return Vehicle design on the CD-ROM in On To Mars, Volume 2.  The one problem with winning the Kepler Prize (ERV design competition) was that it took a LOT of digging to find even one competitor's design.  

I think it would only be fair to discuss each other's designs when mine is visible.  

All the same, my first impression is that you are more "rocket scientist" than I, in terms of orbital calculations, etc.  Mine was more nuts-and-bolts and systems level in approach.  

With Kepler, 20 teams started, 12 made the midterm report, and 5 finished.  With MSR, 6 made the late abstract, and I have no idea how many finished.  One of our competitors on this is Tom Hill - who was a judge on Kepler and designs weather satellites.  Very nice and good guy.  One of the reasons he started that competition is that he wanted to hand it off to someone else to do the next year so he could compete.   No idea how good his paper is, but this IS his day job.  I just try to design things that intuitively work and work well, based on as much engineering history as possible, and not all of that history space-related.  That can be both good and bad.  

Anyway, I look forward to meeting you at either this or the Mars Society conference one of these days.  We have a lot to talk about and I would like to introduce you to some people.
Kent Nebergall

Offline aftercolumbia

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Re: Mars Challenger
« Reply #2 on: 03/11/2007 06:29 PM »
I'm looking forward to Tom Hill's.  It sounds like he has the best chance of getting second ;).  Mine has some typos, too.  Part of the reason is that the development isn't finished.  Of course, I could probably hack at Mars Challenger for years on my own before getting to a point where I can't make it go any further without cutting metal or hiring people...and of course, there development isn't finished either.

Oh, and by the way, the Mars Challenger thread at MarsDrive's forum is more active, if anyone's interested: http://marsdrive.com/phpBB2/viewtopic.php?t=15&postdays=0&postorder=asc&start=0

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