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Fox Cutter
2002-Jun-17, 08:03 PM
This is a very simple question about the Space Shuttle. I'm only asking here as I've been unable to find the answer elsewhere. The board seems to be reasonably filled with experts who could be helpful, so here it goes.

Can the Shuttle's main engines be fired in orbit, (assuming you had full of course), or is it stickily limited to being used in the atmosphere?

--Fox Cutter
http://www.chaos-keep.com/

TinFoilHat
2002-Jun-17, 11:31 PM
The Shuttle Main Engines get their fuel exclusively from the external fuel tank. Once it's jettisoned, they can't be used. They're also non-restartable - even if there was fuel to run them, they can't be started again once shut down. Once fired and shut off they have to be inspected, serviced, and occasionally totally rebuilt before being used again.

Kaptain K
2002-Jun-18, 03:54 PM
TinFoilHat,
Are you sure of that? I was under the impression that:
1) The shuttle main engines draw both from the external tank and from an internal tank.
and
2) That the main engines are used when boosting a satelite (like Hubble) to a higher orbit.

_________________
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<font size=-1>[ This Message was edited by: Kaptain K on 2002-06-18 11:55 ]</font>

Donnie B.
2002-Jun-18, 04:15 PM
TFH is correct. I had this misconception too, but got a correction in an earlier thread.

The main engines get their fuel from the external tank only. All further maneuvers, including the reentry burn, are done with the OMS engines -- different type of engine, different fuels, restartable, and generally pretty slick.

By the way, back to the OP, the question of using the main engines in space has nothing much to do with the lack of atmosphere. In fact, by the end of the main engine burn, they're already operating in a pretty good vacuum. It's really just that the main engines' fuel is outboard (and is fully expended before the shuttle enters orbit), and that they can't be restarted.


<font size=-1>[ This Message was edited by: Donnie B. on 2002-06-18 12:19 ]</font>

Kaptain K
2002-Jun-18, 04:51 PM
Thanks for the correction Donnie B.