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……
Category: Descent abort
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……
Spacecraft computer program – things dealing with lunar descent and aborts from it
I spent an interesting morning at MIT on May 16 with George Cherry, Dan Lickly, Norm Sears, and Craig Schulenberg talking about Luminary how it works and some things that really haven’t been defined yet. It primarily dealt with lunar descent and aborts from lunar descent….
Lunar rendezvous abort summary
A great deal of work has gone on over the years on the subject of lunar abort rendezvous, spearheaded by Morris Jenkins, Ed Lineberry, Buzz Aldrin and others. The results of some of this work have already been documented and more detailed reports are in the works. The primary reason I’m writing this note is…
The LM can handle big Descent plane changes but required protection against APS abort fuel depletion
We have recently verified that the LM has a substantial capability to translate out of its initial orbital plane during powered Descent at very little cost. That is, whereas previously a limit of 0.3° had been quoted, it now appears that 1° or more is probably possible without effecting the performance of the guidance equations,…
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%…
Descent Abort Mission Techniques
On February 13 we went over our Descent Abort Mission Techniques with the world. In general they were accepted as is. That isn’t to say we didn’t have some lengthy discussions resulting in some improvements and/or changes but we didn’t make any substantial changes to the basic ground rules, philosophy, or overall procedures. I would…
AGS/PNGCS incompatability review – Chapter One
At the January 8 meeting of your CCB I was given the action item of reviewing AGS SCP’s Nos. 34 and 35. Specifically, I was to determine our position on the advisability of making these changes which you tentatively approved at that meeting, and, in particular, we are to satisfy ourselves that the AGS and…
Descent monitoring at MCC
We have reached a plateau in our work on Descent Monitoring, perhaps making it worthwhile to send out this memo. First of all, I don’t think there is any question that Descent is the thing that requires most of our attention between now and the G mission, at least in the empire of Mission Techniques….
DPS low level propellant light
During our final review of the Descent Mission Techniques on May 28, GAEC presented a comprehensive review of the low level DPS propellant light – its operation and accuracy. The most significant piece of information coming from this was that we are assured of about 98 seconds more DPS operation at the hover thrust level…