FC/Chief, Flight Control DivisionFEB 7 196868-FM-T-31FM/Deputy ChiefProblem of S-band during lunar landmark tracking
1. Attached are the “antenna” patterns for the S-band and the sextant I referred to during the Configuration Control Board last week. The spacecraft is constrained to point such that the sextant is within that small circle in the middle (with the hair on the inside). The bigger circle that it is superimposed on is the coverage the S-band antenna can provide which you see is in the same direction as the sextant plus a good bit more. The little region surrounding that is supposedly within the coverage of the S-band, but would cause the warning light to come on. The big area to the left and the small area to the right are where the S-band cannot go at all.
2. Marty Jenness, over here, is working on precise attitude time history profiles to show what the actual situation is during a landmark tracking pass. When he finishes within the month we will go over it with you if you are interested.