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: Lunar descent
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……
Requirement for pre-PDI IMU alignment has been deleted
After extensive Mission Techniques Panel review, it has been established that a PGNCS IMU alignment immediately prior to Powered Descent is not required for any reason. It is, in fact, undesirable at this critical time in the mission when lighting conditions couldn’t be worse (local high noon!)…
Lunar Landing Guidance and Control Modes
Gentlemen:…
What’s descent all about?
As a result of some stirring around within NASA on how the various guidance and control systems are used during descent, George Cherry of MIT took it upon himself to write a complete description of the capabilities that exist and how they may be used. Without doubt, this is the finest, briefest, most readable description…
Attention worthy Descent Program Anomaly
Gene Kranz brought the attached G mission LUMINARY Anomaly Report to my attention. I have no idea how he happened to find it amongst all the more insignificant ones. No one else seemed particularly aware or concerned about it, but I wanted to bring it to your attention….
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…
Let’s hear it for “Delta Guidance”!
As part of the Apollo software team’s contribution in the search for extra LM hover time and/or payload capability, they are vigorously working on the development of a new descent guidance and throttle control technique. The pay off could be impressive compared to things like trying to decrease LM weight. Specifically, a ΔV improvement on…
First meeting of the Descent Phase Mission Techniques Working Group
This memo is to request your participation in the detailed development of the Apollo Mission Techniques for the Descent phase of the lunar landing mission. We are setting up a small working group of the following composition to do this job:…