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« Dawn of Modular Spaceflight Revolution | Main | XCORSpace Shot »

More Thoughts On Orbital Armadillos

The problem, Sam, with the cost numbers to orbit are that it's not clear whether or not they're cost numbers to come back from orbit. Yes, the first two stages are presumably recoverable, but does the third one contain enough propellant to deorbit and get all the way back down to the ground, propulsively? There's no TPS in this concept, as far as I can see. If he has to come back down the same way he went up, there has to be a lot of propellant left in the vehicle in orbit for return. It's a question that I didn't ask John yesterday, but I may today.

I know that he has been talking a lot to Lutz Kayser, but I hope he didn't drink too much of the koolaid. OTRAG was, after all, expendable.

Posted by Rand Simberg at March 24, 2007 07:50 AM
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dont invest much thought in this current approach. he will try how far that goes, and if it doesnt look good, he'll switch gears again and keep plugging.

Posted by kert at March 24, 2007 08:39 AM

3rd stage is a single module, $25k and not reusable. Some people don't care about down mass.

Posted by Sam Dinkin at March 24, 2007 09:36 AM

I would imagine that most of the modules would be on the first and second stages.

The third stage might have a different design than
the modules used on the first two; at the very least
I'd imagine they'd use a nozzle with a different
expansion ratio.

A couple of stray comments:

* Sam, a cost of $ 2400/lb. to orbit for a newly
developed system where you can see where all the
money went and can verify that it's not based on
sunk costs being free, or isn't being sold at a
loss in the interests of driving some other
country's launchers out of business... that
would be very revolutionary.

* I think there'd be problems with infinitely
expanding the number of modules... but that after
Armadillo demonstrated the basic concept they'd
suddenly have plenty of resources available to
build larger modules with.

* Since Armadillo builds their own engines,
they're well-equipped to handle changes to their
basic design or plan without being sunk by it.
I imagine a low burn rate helps a lot in this

Posted by Phil Fraering at March 24, 2007 09:41 AM

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