FM7/Chief, Guidance & Performance BranchFEB 5 196868-FM-T-21FM/Deputy ChiefAverage g
During a discussion about reentry at lunar return velocities the other day, the question came up as to when it was okay to turn on Average g. There was some reason for wanting to do this about one-half hour before arrival at 400,000 feet altitude. We all recognized the inaccuracy which results from accelerometer bias, but the thing we were uncertain about was the inaccuracy due to the approximations used in the average g processor itself. Could you guys determine the relative accuracy of the standard numerical integration program used onboard the spacecraft and Average g for a case like this? You probably already know the answer, having worked on 501 and 502.