This memo is to inform you of things that happened at the June 25 ASCCB meeting. Some were quite significant….
Month: July 1968
Lunar rendezvous shaping up
On June 26 we took another wack at the “G” Rendezvous Mission Techniques. I think we now have most of the basic things squared away so that we can get into the detail with some confidence. The most significant decisions were:…
Throttle up time is fixed during the powered descent maneuver
We learned something interesting during our Descent Mission Techniques meeting June 28 from the MIT people there. It dealt with the way the DPS gimbal trim phase of the powered descent maneuver is programmed….
Good news on “C” mission SPS burns
The following is a verbatim copy of a note to me from Rick Nobles…
“C” Mission Clean Up
We’ll try to clean up the rest of the “C” mission open items at a meeting on Friday, July 19, in Room 2032B of Building 30. Retrofire and Reentry will be discussed in the morning, starting at 9 a.m., and Rendezvous in the afternoon – or as soon as we finish the Retrofire session. Attached…
PGNCS Alignment During Hohmann Transfer
The attached IOC presents an analysis which estimates the increase in the probability of an unsafe AGS abort if the PGNCS alignment during Hohmann transfer is not performed. The analysis shows that given that PGNCS fails, the probability of an unsafe AGS abort from hover is increased by less than 0.001……
AGS Performance with no PGNCS Alignment During the Homann Transfer (Task 46)
There is some concern about the capability of the AGS to safely perform an abort from hover without a PGNCS alignment during the Hohmann transfer. This concern stems from the results of Monte Carlo analyses which indicate that the mean minus three sigma for perilune altitude of an AGS controlled abort from hover is less than 30,000 feet (the safe orbit limit), and from single error analyses which indicate that an initial misalignment slightly larger than three sigma results in an unsafe orbit……
Lunar Ascent preparation
At the July 3 Lunar Ascent Mission Techniques meeting we cleaned up the last of the main open items for the phase of the lunar landing mission from LM touchdown to liftoff. We are now ready to go to press for that part of the mission and will hold a world-wide review of it before…
LM Descent abortability computation is proposed
Ed Copps of MIT attended one of our mission techniques meeting recently during which we discussed the use of the LM Descent Propulsion System low level sensor light. This is the light, you recall, which comes on when approximately 30 seconds worth of propellant is still available at full thrust or two minutes at 25%…
Powered descent throttle logic correction
On July 2 I sent you a note regarding the way the DPS is throttled up after the gimbal trim phase during the powered descent maneuver. There were a couple of errors in that memo which are too significant to be left uncorrected….