Re: SPACE: Indian reusable space plane

From: Doug Jones (
Date: Tue Aug 28 2001 - 13:48:47 MDT

"Robert J. Bradbury" wrote:
> It looks like India may be getting into the space development
> business. They've designed a reusable space plane (the Avatar)
> that they claim will significantly lower launch costs for 1 ton
> satellites (much bigger than what we need to bring back an asteroid).
> URL:
> The key trick is to gather and liquefy the oxygen in the air
> rather than carrying it up from the surface. They say the idea is
> based on a Rand report published in 1987.
> Anyone have any comments on why this idea hasn't been pursued
> more seriously in the U.S. or Russia? It would seem to me
> the tricks here require relatively lightweight machinery
> for performing the liquefication and separation.

The air handling equipment is fairly massive and requires very very
delicate heat exchangers- the liquid hydrogen is passed through millions
of stainless steel tubes with wall thickness in the single micron
range. Dana Andrews gave a presentation at Space Access this April-

It has been described by some viewers as a "single stage to NASA
funding" design- tech candy which pushes the threat of cheap access to
space decades into the future.

I have several objections to air liquefaction systems-

* the system is massive and startlingly complex, thus expensive and
* the oxygen it produces has substantial argon and nitrogen
  contamination, reducing performance
* bulk LOX at $0.05/lb is the second cheapest liquid after water
* the fuel _must_ be hydrogen, increasing vehicle bulk and drag
* the system must have airbreathing engines which *also* must be
  hauled to orbit- or else the system is no better than a simple
  two-stage rocket. Two stage to orbit is easy- why bother with
  making LOX?

This all boils down to an impractical, expensive, unreliable, overweight
system which is extremely unlikely to result in a useful vehicle. It
smells like son of X33 to me.

Doug Jones, Rocket Plumber
(Speaking for myself only)

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