54
votes
Could the Columbia crew have survived if the RCS had not been depleted?
You are misreading the accident report. By 14:00:02, the vehicle had already begun to lose structural integrity, it had already begin to lose thermal integrity, and it had completely lost control ...
- 72.5k
33
votes
Could the Columbia crew have survived if the RCS had not been depleted?
The RCS wasn't depleted. The RCS firing was a symptom of a main issue, and it happened very late in the timeline, at 13:59:29. The RCS fired after the spacecraft's left yaw went beyond the capacity of ...
- 19.9k
30
votes
Accepted
How dangerous are RCS thrusters?
For Shuttle EVA, the Space Shuttle Flight Rules show that the safe
distance for a suited crewmember was 27 feet for the main jets, 3 feet
for the vernier jets, and 3 feet for the APU exhaust. It's ...
- 177k
28
votes
Accepted
Was the Space Shuttle ever rotated to induce artificial gravity?
There are several reasons not to do this:
Artificial gravity in such a small space is not very pleasant. You'll get a noticeable difference in gravity in different places, which makes it difficult ...
- 124k
22
votes
Accepted
Why aren't RCS openings an issue for spacecraft heat shields?
The columbium jet nozzles themselves can take the heat, but "penetrations" of the spacecraft heat shield are a definite potential failure point, including penetrations for the Reaction Control System (...
- 177k
18
votes
What does "reaction" in "reaction control system" and "reaction wheel" refer to?
I think there is little doubt that "reaction" refers to the "equal and opposite reaction" of Newton's third law.
First consider "reaction control system". In principle, ...
- 9,819
17
votes
Was the Space Shuttle ever rotated to induce artificial gravity?
The highest rotational rate ever achieved by a shuttle in orbit was only 3 degrees/second (approximate). This was inadvertently caused when Mission Control uplinked a bad state vector during crew ...
- 177k
15
votes
How dangerous are RCS thrusters?
A space ship may need some protection against the heat of its own RCS thrusters.
The Apollo Lunar Module was covered with multiple layers of thermal insulation foil. Close to the RCS thrusters the ...
- 48.7k
13
votes
Accepted
Why does the Psyche Spacecraft use cold gas thrusters?
Its like looking for a needle as all eyes are on the Hall thrusters.
TL;DR:
Why does the Psyche Spacecraft use cold gas thrusters?
Psyche was always designed for the main propulsion to be electric ...
- 8,757
12
votes
Could the Columbia crew have survived if the RCS had not been depleted?
Actuator saturation is a control systems terminology. It means that the required (requested) control input exceeds the physical limitations of the actuators.
For example once a valve is fully open you ...
- 121
12
votes
Accepted
"Re-entry" vs "Reaction" in RCS
The Orbit Attitude and Maneuvering System (OAMS) was for orbit and was jettisoned before the retro burn, leaving the RCS for reentry.
The complete OAMS had 16 small engines, which burned hypergolic ...
- 177k
11
votes
Accepted
Is it possible to use RCS instead of gimbal to control first stage attitude?
As Organic Marble notes, some single-engine stages do use RCS for roll control since the requirements for roll on ascent are less demanding than pitch and yaw.
The Falcon 9 first stage also uses RCS ...
- 166k
11
votes
Accepted
Why were the apollo CM RCS thrusters all placed in only one half of the module?
The CM entered the atmosphere blunt-end first, which became the hottest part during re-entry (see picture below left). So you can't place RCS thrusters on that part of the CM, as they would melt; you ...
- 47.6k
10
votes
Accepted
During the MSL (Curiosity) Mars atmosphere entry, when was the last time the Reaction Control System used?
TL;DR: It is used unto the very end, so somewhat near $0\ \mathrm{km}$.
The RCS is used in re-entry right from the Entry Interface ($125\ \mathrm{km}$ from the Martian surface, $5,900\ \mathrm{ms^{-1}...
- 1,271
9
votes
Calculating mass expelled from cold gas thrusters
The concept and formula are correct for a coherent system of units. You have chosen to use US customary units and these are not a coherent system, i.e. in the situation in the OP one is bound to run ...
- 9,264
9
votes
Accepted
Apollo SM RCS specific impulse?
Some resources (Wikipedia, Astronautix) give 312 seconds for the R-4D, but I think that's for the large-nozzle modern version.
Marquardt's "Apollo SM-LM RCS Engine Development Program Summary Report"...
- 166k
7
votes
What are the limitations of monopropellant RCS thrusters in a re-useable spacecraft?
Monopropellants are less efficient than most serious bipropellant rockets, including hypergolics (though hypergolics are themselves less efficient than some other propellant combos). In impulse per ...
- 1,532
6
votes
Accepted
What is the minimum number of RCS thrusters capable of stabilizing a satellite against an arbitrary rotation?
Your suspicion that it can be done with 4 is correct, and the method you suggest will work.
More formally, to prove that a set of thrusters allows arbitrary torque is equivalent to showing that you ...
- 1,704
6
votes
Accepted
Could Vostok 1 deorbit on its cold gas thrusters?
Not likely. For early manned missions, rendezvous wasn't a requirement, so thrusters provided only for rotation, not for translation. According to this reference:
In each of the two [redundant] ...
- 166k
6
votes
What does "reaction" in "reaction control system" and "reaction wheel" refer to?
As Organic Marble mentioned in a comment, "reaction" is used in the same sense as Newton used it: "equal and opposite reaction". A reaction wheel is designed to produce a reaction, ...
- 15.9k
5
votes
Calculating mass expelled from cold gas thrusters
Puffin's answer is correct; this is just a supplemental that was a bit too involved for a comment.
A physical interpretation of specific impulse measured in seconds is "the length of time for ...
- 166k
5
votes
Accepted
Apollo CSM RCS maximum number of simultaneously active engines?
Service Module RCS: 8 max
There are 16 engines total, arranged in four groups of four ("quads").
You can fire 8 of the engines by placing the Direct RCS switch to <...
- 47.6k
5
votes
Why aren't RCS openings an issue for spacecraft heat shields?
An "RCS opening" is a rocket nozzle, which has to withstand massive heat loading from engine burns. Massive enough that the nozzle will also withstand the heat load on reentry.
You just have to make ...
- 124k
5
votes
Is it possible to use RCS instead of gimbal to control first stage attitude?
Although perhaps larger than what would normally be considered RCS, the Ares-1X solid rocket booster did use jets to control its roll attitude in first stage (its only stage, for this test).
Pitch ...
- 177k
5
votes
RCS jet select algorithms (e.g. in space shuttle)?
sub-partial answer...
Shuttle used a table lookup method to determine which jets to fire for a desired maneuver. If the full tables are available online, I am not aware of it, but there were some ...
- 177k
4
votes
Accepted
Why does candidate optimal group computation produce strange results when thrusters are too close together?
It turns out I made a dumb math error (a transposition, specifically), related to this math.stackexchange question. In short, I was computing $\mathbf{\lambda} = \mathbf{\hat{A}}^{-1}\mathbf{\hat{c}}$ ...
- 1,090
4
votes
Accepted
Apollo CSM mass, inertia and RCS parameters?
I think the CSM/LM Operational Data Book Volume III: Mass Properties has what you're looking for.
Because mass and mass distribution vary as consumables are consumed, I don't think it provides a ...
- 166k
4
votes
Accepted
Is there an alternate term to "fired" for the Reaction Control System?
One can "start" or "execute" the "burn" or the "maneuver".
Examples are found in the Shuttle Crew Operations Manual
on page 7.2-3
To perform an automatic maneuver, the crew first enters the ...
- 177k
4
votes
Dragon RCS: Four controlled degrees of freedom... or six?
Assuming this simulation is correct, and I have no reason to doubt that it is, there is in fact true 6 degrees of freedom of movement possible. I do recall that at least one of the axis has less ...
- 121k
4
votes
Attitude control of rockets with RD-107 engines
RD-107 seems to have been used in the R7 missile. It says in the article for the missile that
1st stage: 4x jettisonable four-chamber RD-107 booster engines each with 2x vernier rocket engines plus ...
- 968
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