TRW Systems released the AS-207/208 Preliminary Spacecraft Reference Trajectory during the first week of May. This report was put together on a compressed schedule, starting from rather hastily defined mission requirements. As a result, there are a number of things about it which were recognized as being in error even before release; however, since we…
Category: Mission phases
CSM orbit determination using the LEM radar
Apparently it is planned to use the LEM radar while that spacecraft is sitting on the lunar surface to determine the CSM’s orbit. I am told that the radar angle data accuracy is so poor it will not even be used; the command module’s orbit determination will be carried out with range and range rate…
No special program available for targeting the CSM plane change in lunar orbit
As I understand it, it is currently planned to make a plane change with the CSM in lunar orbit within the last several revolutions prior to LEM ascent. The purpose of this maneuver is to optimize the sharing of maneuver (propulsion) requirements between the CSM and the LEM….
Determination of relative CSM orbit
Jim, this is just a reminder of conversations with you and Emil about a job I’d like your people to do. In thinking more about this orbit determination task wherein the LEM determines the CSM orbit while sitting on the lunar surface, I wonder if perhaps MIT has lost sight of our primary objectives, thus…
LEM radar angle bias correction
As you know, the rendezvous orbit navigation process involves updating the spacecraft state vector based on the spacecraft radar data. However, the radar apparently has unacceptably large angular bias errors for some reason. Instead of fixing the damn radar, someone decided to include in the LEM spacecraft computer program the capability of computing these radar…
Rendezvous terminal phase guidance program in the Apollo spacecraft computer
On July 7, 1966, a team of MSC and MIT “experts in rendezvous” (including Paul Kramer, Ed Lineberry, John Dablen, and Norm Sears) met at MIT to discuss and review the preliminary Guidance System Operation Plan (GSOP)which MIT has unofficially distributed, covering the terminal phase and External ΔV programs for the AS-207/208 mission. This meeting…
Automatic rendezvous braking maneuver
As you know, MIT is currently designing the command module and lunar module computer programs without provision for automatic braking maneuvers. There has been some thought to reversing this direction. However, Don Cheatham, Aaron Cohen, and I agreed today to proceed as we are for the AS-207/208 programs–that is, do not provide automatic braking maneuvers…
Status of the lunar module “quick return” guidance capability
This note is in response to your query regarding the “quick return” capability being provided in the lunar module (LM) for aborts during the lunar descent phase. As you recall, I reported deletion of a program in the LM computer for generating coefficients to be used in an abort polynomial to retarget the LM powered…
Alternative rendezvous technique – mission planning status
Since our meeting in your office on the stable orbit rendezvous, Ed Lineberry and I have met on a number of occasions with other interested people in an attempt to lay out a schedule of work needed to arrive at the decision as to how to go on 278 and subsequent missions. This note is…
There are differences in the descent guidance programs on AS-503 and AS-504
It is currently intended to include some sort of tests of the LM descent propulsion and guidance on the AS-503 mission. However, it is not possible to use the same guidance equations on AS-503 as will be used on the AS-504 lunar descent. This is due to obvious differences of an earth orbital mission compared…