A lot of activity has been going on lately regarding the manner in which the DPS gimbal drive actuator (GDA) is managed during descent. This memo is to make sure everyone knows this business is going on and producing dramatic changes – and it is not finished yet….
Month: July 1969
Post-insertion alignment is lower priority than rendezvous navigation
It has been agreed that it is more important for the LM to obtain rendezvous navigation tracking data than to complete the platform realignment after insertion into orbit if problems occur which prolong it. The point is, an accurate CSI maneuver is vital but it is recognized that bad angle data does not substantially degrade…
Some new ideas on how to use the AGS during Descent
This memo is to fill you in on a couple of late crew procedure changes proposed for the G mission regarding AGS operation during descent. The first is a technique to prepare the AGS for immediate ascent which can be used to quickly reinitialize the AGS LM state vector immediately after touchdown if there is…
Manual Ascent revisited
On July 2 we had another meeting regarding Manual Ascent. As I have pointed out previously, the consensus is that the crew should have an excellent chance of achieving a safe orbit by manually steering the LM from the lunar surface if they have a rate command attitude control system by using the horizon view…
Tweak burns
If you can stand it I would like for you to hear the latest on tweak burns – the trim maneuvers made after LM insertion from a descent abort. I thought we had this settled and on ice a couple of months ago but some things have happened which probably make it logical to revise…
Descent Data Select procedures are finalized
On July 7 and 8 we held a final review of the Data Select procedures and Flight Controller interface during the Descent phase of the lunar landing mission. This lengthy memo is to describe briefly some of the items discussed, all of which are being thoroughly documented before the flight….
Descent monitoring after landing radar velocity updating
There has been considerable discussion concerning the capability to monitor powered descent with velocity residuals after landing radar (LR) velocity updating begins. This memorandum presents the recommendations of the Mission Planning and Analysis Division (MPAD) for powered descent monitoring during this period of powered descent….
How we will handle the effect of mascons on the LM lunar surface gravity alignments
What do we do if one of those big damn lumps of gold is buried so near the LM that it screws up our gravity alignment on the lunar surface? Without exception, the calculations of all the various far-flung experts predict that mascons should have no significant effect on our lunar surface gravity alignments. In…
Change in delayed PDI Descent targeting procedures
This probably doesn’t amount to a gnat’s elbow to you, but I would like to change something in a memo that I just sent out the other day dealing with spacecraft state vector updating if we delay PDI one rev. Previously we planned to leave the state vector in the LM computer alone but to…
Gyro calibration and accelerometer bias update and redline values
Chuck Wasson wrote a memo, dated June 27, 1969, to Gene Kranz and me defining in detail the Guidance and Control Division’s (G&CD’s) position on “in-flight gyro calibration and accelerometer bias update and redline values.” In it he pointed out that both the Mission Rules and the Mission Techniques Documents should be brought into agreement…