Upthread: Apollo Spacecraft Software Configuration Control Board notes for March 4 meeting (Mar 07, 1968)
Downthread: Results of the Apollo Spacecraft Software Configuration Control Board meeting of April 9 (Apr 16, 1968)
See list belowAPR 1 196868-FM-T-65FM/Deputy ChiefApollo Spacecraft Software Configuration Control Board notes for the March 19 meeting
1. We spent another couple of hours talking about the Delta V monitor programs. Two program change requests were considered for Sundance and Luminary. It was concluded that no change would be made to Sundance, but that both changes should be made to Luminary, although, I am not sure if one of them is not in there already. Specifically, PCR 121 provides a new engine fail monitor which does not turn off the engine in the event the Delta V is not detected, and PCR 122 reduces the ullage over- lap such that is now stopped based on time, specifically, 1/2 second after time of ignition. This present logic stops ullage when the Delta V monitor detects engine ignition which could be as much as six to seven seconds later. It was also noted that the Delta V monitor threshold in Sundance must be made low enough to insure that the DPS engine will not be cut off on the early LM flights when that engine is used in either the docked or undocked configuration.
2. It was also decided to change the Colossus Delta V monitor/engine fail routine to make it the same as Luminary as far as crew procedures are concerned. This costs 14 days schedule slip.
3. The PCR's dealing with the new DSKY lights are being withdrawn and will be replaced by a more comprehensive one sometime in the future.
4. PCR No. 57, a DAP hand controller change, was disapproved.
5. PCR No. 70 provides a change in the Luminary abort programs P-70 and P-71 decreasing the early descent abort zone from 150 to 50 seconds and adds the jerk limit logic like the AGS. This PCR was approved at the cost of three days.
6. PCR No. 77, a modification to the LM DAP in Luminary, was also dis- approved.
7. PCR No. 89 would move the rendezvous radar range and range rate vari- ances into erasable memory to permit changing their relative weight in the rendezvous navigation, if the radar does not meet specification. This would have cost five days in the Sundance delivery, and it was disapproved. As you recall, this same capability was approved at the last meeting for Luminary and Colossus.
8. PCR No. 90 was to put a valid data indicator on the landmark track- ing downlist in Colossus. It was determined that control center work around procedures could be developed using the program as it is currently programed, and so this PCR was disapproved.
9. PCR No. 91 would change the Luminary and Sundance programs to put a special identification on the erasable memory dump downlist such that the RTCC could distinguish this data as coming from the LM, as opposed to the command module; since this could be done with no impact, it was approved.
10. PCR No. 98 for Sundance and subsequent would have provided the capa- bility of moving the rendezvous radar antenna out of the way of the AOT so that it would be possible to do a platform alignment when the rendezvous navigation program (P-20) was running. It would have cost 1� days, and since it would not seem to be particularly necessary, it was disapproved.
11. PCR No. 99 would have made the display of radar pointing angles more meaningful when operating in mode II. It was not needed on Sundance, so that was disapproved. MIT estimates a visibility impact of two days for Luminary and so they were requested to prepare a detailed schedule impact for Luminary. This would put the DSKY display of radar angles in the azimuth/elevation coordinate system consistent with the crew's orientation.
12. PCR No. 100, a program change requested by George Cherry (MIT), was approved. The change has already been made and so there is no impact. It is to eliminate a rate test from the thrust vector filter.
13. PCR No. 105 was to delete the LM/CSM separation program (P-46) from the Luminary program. This was approved and should advance program delivery five days.
14. PCR No. 106 was to eliminate the Direct Transfer Ascent Targeting program (P-11) from Luminary. I was given the action item of making sure that this deletion does not affect the stable orbit rendezvous capa- bility. In addition, I was requested to look into deleting the coelliptic ascent targeting program (P-10) which provides an onboard capability which is only needed if communications are not available with the ground.
15. PCR No. 114 was approved to delete a minimum deadband mode during minimum impulse burn in Sundance.
16. PCR's 115, 116 and 117 were minor changes to the way the LGC throttles the DPS. They would put throttle up time in a readily addressable address, would delete the �� second 10 percent thrust test, and would make it possible to automatically throttle to a value lower than maximum thrust. These changes were all disapproved for the first series of Luminary, but were put in the hopper for consideration for Luminary 2 and beyond.
17. The next meeting, as I understand it, will be on April 2, 1968.