On October 5th, we had the second of our weekly all day program development plan meetings at MIT. Most of our attention was given to the open items on the AS-278 program which I will discuss later, but first I would like to pass on some general comments regarding the work at MIT. Based on…
Category: Reentry
Small program change needed in the AS-501/502 AGC program
In the course of development of the AS-206 computer program at MIT, a coding error was discovered which was immediately recognized as being common to the AS-204 and AS-501/502 programs. It is a scaling error, if you know what that means, which imposes the operational constraint of not operating one of the integration programs (i.e.,…
State vector update situation for AS-501 and AS-502
The AS-501 and 502 missions have been designed to update the state vector (position and velocity) in the Apollo Guidance Computer (AGC) with a state vector from the Manned Spaceflight Tracking Network (MSFN) prior to the Saturn (S-IVB) out-of-orbit burn and again prior to the second Spacecraft Propulsion System (SPS) burn. If these updates are…
State Vector Update Criteria for AS-501
Because of the decision to utilize the AS-502 Apollo Guidance Computer programs for the AS-501 mission, the mission was designed and developed on the premise that the state vector updates __would__ be made. ���������� this, the situation exists that a __perfect__ launch vehicle spacecraft combination __without__ guidance or propulsion errors of any kind will land…
AS-258 RTCC Retrofire Time Computation
One step taken in an attempt to alleviate the RTCC program development problem has been to make major reductions in the area of retrofire time computations. Since these deletions have an impact on the Retrofire Controller’s capability and mode of operation, I felt it desirable to report these things in a memorandum devoted solely to…
Reduced L/D presents a spacecraft computer program problem
This note is to help unsure that the word gets around regarding reduced command module reentry L/D. MIT has heard rumors that the L/D may be reduced to a value of .25 and emphasized during our program development plan meeting that they are fairly certain the present spacecraft computer program formulation will not handle that….
Greater dispersion at entry on AS-501 with the new IMU
You have expressed concern about the somewhat poorer performance of the new platform in Spacecraft 017. While at MIT last week Dan Lickly and I spoke to John Miller about this. John says the component which contributes the most to dispersion in flight path angle at the entry interface is the Y gyro, as you…
New/old platform for AS-501
Cline Frasier told me today that the platform in Spacecraft 107 (that is, AS-501) has been replaced again by the one that was taken out several weeks ago. Apparently, there was an intermittent problem in one of the accelerometers. I believe Cline said they have replaced the Z-gyro. This change should be beneficial in terms…
Reentry guidance is perfect for S/C 101 regardless of L/D
This memorandum is in response to your question regarding the reentry guidance with low L/D. It was erroneously reported to you in the August 3 MPAD Weekly Activity Report that, although the program could be modified easily to handle L/D as low as 0.2, it probably would not be implemented for Spacecraft 101. Actually, some…
Is display of max g in P-61 any good?
During our lunar landing GSOP review someone commented that the display of max g in P-61 is of no use at all. It was said to be grossly in error for earth orbit reentry and of no value in determining appropriate action during entry from lunar return or following an abort when it is more…