Informal DistributionFEB 25 196969-FM61-47FM6/Chief, Orbital Mission Analysis BranchComparison limits for rendezvous radar test on Apollo 9
Reference: Shannahan, Philip: Rendezvous radar checkout for Apollo 9, OMAB Memorandum 69-FM62-38, Feb. 20, 1969.
The comparison limits for the rendezvous radar test on Apollo 9 were determined by OMAB and documented in the above reference. Recent studies conducted by MIT/IL have pointed out an additional error source not con- sidered in the OMAB analyses. This error source results from the compu- tational inaccuracies in the Rendezvous Parameter Display Routine (R31) for range and range rate based upon the vehicle state vectors. At the very close range at which the radar test is being conducted ( 0.6 n. mi.) the computed range can be in error by 600 feet and the range rate by 2 fps. This information was relayed by Mr. Malcolm Johnston of MIT/IL via a telephone conversation on Feb. 24. Inclusion of this error source results in limits as follows:
Range comparison 1600 feet
Range rate comparison 7 fps
The revised limits have been relayed to Mr. R. Carlton of FCD and Mr. M. Contella of FCSD.