Do rcs perform well in the presence of high aerodynamic forces?

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    $\begingroup$ Welcome, your question seems to be lacking information that would allow it to be answered. An arbitrarily large RCS could handle 'high' aerodynamic forces. Suggest editing the question to either ask how a known craft with complex loads (EG space shuttle) achieved control or ask for details on existing RCS system mass and performance. $\endgroup$ Dec 4, 2021 at 11:00
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    $\begingroup$ Before editing your question suggest checking the following space.stackexchange.com/a/8433/26356, space.stackexchange.com/q/43762/26356 and space.stackexchange.com/q/49772/26356 $\endgroup$ Dec 4, 2021 at 11:12
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    $\begingroup$ It's been used a lot, so somebody thought so space.stackexchange.com/a/20759/6944 space.stackexchange.com/a/56035/6944 $\endgroup$ Dec 4, 2021 at 13:35
  • $\begingroup$ @GremlinWranger shuttle didn't use RCS "during the atmospheric phase of the launch vehicle" except in some exotic multi-engine-out and/or propellant dump scenarios. $\endgroup$ Dec 4, 2021 at 14:31
  • $\begingroup$ Easier to use aerodynamic surfaces and/or gimbal the main engine for thrust vectoring than use rcs for the ascent stage. $\endgroup$
    – Innovine
    Dec 4, 2021 at 19:13

1 Answer 1


RCS of any sort loses ISP in atmosphere, and thus thrust, the same as any rocket engine (because that's all they are).

However they will only become completely ineffective if the apparent pressure on them is greater than their chamber pressure, which never happens.

What is more of a concern is sizing the RCS to be strong enough to overpower the sum of the aerodynamic forces on the vehicle, which can be huge.

Realistically, aerodynamically active surfaces are much more practical in the atmosphere. Whether they be fins, or gridfins, or static surfaces(wings) or dynamic surfaces like the Starship's , erm,... flaperons (or whatever they've settled on calling those things)

Example: the X-15 plane used aero surfaces for control while in enough atmosphere to do so, and only when so high that the air was too thin, did it rely on its RCS for control.


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