[AR] Re: Flying to Orbit with Hydrogen?
- From: "John Dom" <johndom@xxxxxxxxx>
- To: <arocket@xxxxxxxxxxxxx>
- Date: Wed, 18 Dec 2019 20:35:59 +0100
So no H2O2 propellant :-( used if you are correct. Could have read that
before... and forgot.
John D.
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Henry Spencer
Sent: woensdag 18 december 2019 19:41
To: Arocket List
Subject: [AR] Re: Flying to Orbit with Hydrogen?
On Wed, 18 Dec 2019, John Dom wrote:
Talking hydrogen peroxide once more, the USAF?s X-37B engine burns
kerosene fuel in *HTP*.
Alas, while that was the original intent (and you can still find that on
some reference sites -- the USAF X-37 people are so secretive that much of
the information on it is quite old), it was changed to a more orthodox
N2O4/hydrazine system fairly late in development. See, for example,
<
https://www.airspacemag.com/space/spaceplane-x-37-180957777/> or
<
https://space.skyrocket.de/doc_sdat/x-37.htm>.
Reportedly, the original use of peroxide was driven by shuttle safety
constraints -- X-37 was meant to fly in the shuttle cargo bay -- and the
decision to switch it to expendable launch may have triggered the change
of propulsion.
To put an X-37B in orbit requires a big rocket, unfortunately.
Yep, no less than an Atlas V. When it got moved off the shuttle, it was
first slated to go up on a Delta II, but that would have meant launching
it exposed, and all the usual problems of putting a lifting shape on top
of a rocket came up. Using an EELV instead meant it could go up inside a
payload fairing, eliminating the aerodynamic and structural issues.
Henry
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