See list belowDEC 7 196767-FM-T-111FM/Deputy ChiefLight weight LM attitude control is too sporty.
1. Pete Conrad expressed concern the other day about a problem he anticipates in attitude control of the LM. This has popped up on a number of occasions previously, but nothing much gets done about it. Specifically, as Pete says, the LM is too sporty when in a light weight configuration. Minimum impulse is expected to produce about 0.3°/sec. attitude rates which is said to be about 4 times too fast.
2. I am writing this note just to prompt some more thinking about this problem which may become quite serious. I certainly don't know what to do about it. Pete suggested that we should look into differential thruster firing. First reaction to that suggestion is that it would use too much RCS propellant. But if you consider how much will be spent limit cycling at 0.3°/sec., there is some reason to believe differential jet firing may be no worse. And, of course they may be able to control the spacecraft which is highly desirable, if not mandatory. (Differential firing, or course, is the business of firing jets whose reactions oppose each other by controlling their difference to be the small, desired reaction in the right direction.)
3. Who has a better idea, or do you think the present design is okay?