JayUtah
Penultimate Amazing
No, the question was how long it should take for thrusters to stop the LM rotation. You're comparing what you see in the film to what you suppose it should take. I want to know how you determined how long it should take.
In other words: I'm an engineer; show me the numbers.
The ignition transient for a 100-lbf Marquardt thruster is a published figure. It's longer than zero seconds, but it's much, much shorter than 100 milliseconds.
Keep in mind I said these thrusters were used in pulse mode. In pulse mode they only fire for a few milliseconds anyway, because they are quad thrusters used on an outrigger creating a moment arm of about 12 feet. That's 100 times 12, or 1,200 foot-pounds, times 4 for quad thrusters, giving 4,800 foot-pounds of torque.
Now it's up to you to estimate the actual moment of inertia for the largely-empty ascent stage, dry mass about 2,500 lbm. Then you can speak intelligently about how fast it should take those thrusters to stop a rotation. Until then you're just blowing smoke.
Keep in mind that this thruster system was designed for a spacecraft that initially massed almost 20 times as much as it does in those films. It was designed to produce effective control moments for that mass. Imagine what it's going to do when the moment of inertia is on the order of 20 times less.
Oh, and if you knew anything about rocket motors you'd realize that they actually generate more thrust during the ignition transient than they do at steady state. That's how pulse mode works.
Yes, but you have no idea how long that ramp-up function is for the Marquardt 100-lbf thruster. It's a published figure, but you're too lazy to go look it up, and you'd probably just accuse them of faking the data if it didn't support your belief.
Time for you to do some homework.
Begging the question. I'm asking you how long the deceleration phase is. You seem to know, since you're saying the film depicts something inaccurate. But of course you actually have no clue how long the deceleration phase should be, because you haven't actually done the computation. You're trying to tell us it would be too difficult to compute, but in fact there are people who do them for a living. They're called engineers, and they disagree with your ignorant belief.
Maybe you should look into why, in guidance-system slang, this is referred to as "bang-bang steering."
It's really amusing to see how much you're willing to tap dance before admitting that you simply don't know what you're talking about.
