Just wanted to give everyone a quick reminder that I’ll be appearing on The Space Show later this afternoon (2-3:30pm PST) to discuss Altius, what we’re up to, our recent SBIR win, and where we’re trying to go. I’ll probably flesh some of these topics out later in a blog post, but if you have time, I suggest listening-in at: http://www.live365.com/stations/dlivingston?site=pro
[Update 1: As I mentioned in my interview, here is the link to the paper I coauthored that discusses various approaches to depots, cryogenic fluid management, and implementation: Realistic Near-Term Propellant Depots: Implementation of a Critical Spacefaring Capability]
[Update 2: Here’s a link to the Space Show archive for the show: http://archived.thespaceshow.com/shows/1476-BWB-2010-12-13.mp3. If you guys have any questions, comments, flames, violent responses, etc. consider this an open comment thread. If you could focus questions or comments here on the Altius Space Machines side of things (sticky boom, what we do, etc), and pop over to Selenian Boondocks for questions/comments related to depots, space exploration, etc, that would help.]
Good show, son! I got a couple of good quotes out of it that I’ll plagiarize the hell out of at every opportunity.
Uh oh. Should I be afraid?
Best wishes to you and your new company picking up the baton and running with it.
I read the paper on depots that you mentioned and also your Selenian Boondocks blog on glide-forward TSTO
I was wondering about propellant depots; has much thought been given to figuring out what is the best fuel for a depot to store?
Without depots, hydrogen is the best answer due to its high Isp.
From what I read about depots, so far, hydrogen seems to be the default answer, but it is not obvious to me that it is the best answer.
Hydrogen is difficult to store long-term in space and there is a practical upper limit on the volume of a depot’s fuel tank in that it can not be larger than the fairing of the rocket used to launch it. Might you be able to get more total delta-v from a less complex depot if it used a more storable, more dense, fuel even if it has a lower Isp?
I just read on SpaceBiz you’d won SBIR funding? If so, congrats.
“our recent SBIR win”
<Sigh> One day I’ll learn to read first, post second. Anyway, congrats.
I’ve already muddied up the thread, I may as well try to contribute something useful…
“what is the best fuel for a depot to store?”
Whatever your client uses. At this stage, the depot-idea is too new/fragile to influence mission decisions. So if your first market is servicing satellites in LEO, you’re storing hydrazine. If it’s topping up LH/LOx upper-stages, you’re aiming for dual cryo. If it’s ion-drives, cryo-nobles are your goal.
Which means it depends on who first gets the funding. If it’s a private start-up (like Jon and Colin’s idea on Selenian and SpaceBiz) it’ll be hydrazine. If it’s for NASA manned spaceflight, it’ll be LH/LOx. If it’s long duration robotic, via ion drive, then something like xenon.
(And because of that, I suspect where it ends up, even in 100 years, may well be equally arbitrary. Because once depots are proven, then whatever that first customer used becomes the defacto standard for anyone who subsequently wants to exploit depots. Thus everything gravitates to that “standard”. In the same way that hydrogen-fuelled cars faced such an uphill battle, can’t justify filling stations without customers, can’t get customers without filling stations. So it’ll do no good trying to work out the perfect fuel, people like Jon will have to keep an eye on problems and developments in every possibility, because you’ll never know where the market will break through.)
Anyway, Merry X, Joyous H, Happy NY, and all that.
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