See list belowNOV 17 196767-FM-T-109FM/Deputy ChiefSpacecraft computer program orbital integration
1. This is just another little golden nugget for your files.
2. The spacecraft computer programs, of course, have orbital integration routines to support operations around the earth and moon, as well as in between. The gravitation of the earth, moon and sun are treated differ- ently dependent on which of these regions you are operating in. On a number of occasions the question has arisen as to where the boundaries actually are governing this.
3. I have found out that MIT currently has written the command module program as follows. When operating within about 210 nautical miles of the moon's or earth's surface the orbital integration only takes into account the gravitational potential of that body including its oblateness effects. Beyond that altitude, and up to a radial distance of 42,500 nautical miles from the earth and 8,500 nautical miles from the moon, it adds to these the effect of the other two bodies (without their oblate- ness). Beyond that distance, the oblateness effects are dropped.
4. In order to save erasable memory in the LM computer, the LM program is somewhat different. No matter how high it is flying, it takes into account only that body around which it is operating including all its oblateness effects, but never takes into account perturbations caused by the gravitational potential of the other bodies.