We were informed at the Sundisk Pre-CARR meeting at MIT on January 25 that the CMC landmark tracking initialization data the crew is to use must be referenced to the Fischer ellipsoid. I’m talking about the numbers listed on their landmark photographs, etc., used during the navigation exercise. I could not remember what we were…
Month: February 1968
Can we plan nominally to burn the APS to fuel depletion?
During our Ascent Mission Techniques meeting on January 31, something rather important came up. It was thought by several of the people there that it is now considered acceptable to burn the APS engine to fuel depletion. If this is the case, I am sure we would change the way we intend to perform the…
Rendezvous radar will be available during critical mission phases.
Something rather astounding happened at the Apollo Spacecraft Software Configuration Control Board meeting on Tuesday, January 30. It was so shocking the word spread like wildfire! But just in case you have not already heard, it looks like we are going to get rendezvous radar data on the downlink during the critical LM powered flight…
Average 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,…
Invitation to DPS throttling for DOI meeting
This memo is to notify you of a long overdue meeting. Even I have been aware for at least a year and a half of the lack of definition of the spacecraft computer program requirements associated with throttling the descent propulsion system (DPS). During that time we have gone through a whole series of program…
Sundisk range rate computation is not real accurate.
As you know, one of the key parameters displayed during rendezvous is range rate based on the current state vectors in the computer. During our Sundisk Pre-CARR meeting at MIT on January 25, it was reported that due to approximations used in its computation, this parameter inherently has an error that can grow to as…
Sundisk W-matrix is a little weird.
During our Sundisk Pre-CARR meeting at MIT on January 25, Jerry Levine gave us a one hour briefing on some idiosyncrasies in the handling of the W-matrix during the navigation programs. Generally speaking, they involved the manner in which it is propagated with time. I do not think the way we have the mission set…
Lunar Reentry Mission Techniques meeting
On February 1 we had another meeting on lunar reentry mission techniques. Almost all of our discussion dealt with the final midcourse maneuver prior to entry. As you know, midcourse maneuvers are currently planned to occur approximately 12 hours after TEI which is near the sphere of influence of the moon and about 15 hours…
Problem of S-band during lunar landmark tracking
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…
Third Mission “C” Rendezvous Mission Techniques meeting
Based on our two previous meetings, TRW had prepared the first version of the mission techniques flow diagrams for the “C” Mission Rendezvous. This meeting on February 2 was devoted to going through that flow. As usual, in spite of the fact we thought we had everything all worked out, we ran into numerous items…