Apollo spacecraft computer program newsletter

See list belowFebruary 19, 196969-PA-T-27FM/Deputy ChiefApollo spacecraft computer program newsletter

Christopher C. Kraft has a Joint Program Development Plan meeting at MIT on February 12. I would just like to pass on to you a couple of things that were interesting to me.

1. Fred Martin stated that there are 90 separate changes being made to the COLOSSUS 1A program in developing COLOSSUS 2. Altogether this involves a change of about 2,000 to 2,500 lines of code of which about 800 are the CSI/CDH addition and about 600 involve improvement to the TVC DAP. COLOSSUS 2 was released for rope manufacture on February 11. This release is called Comanche Revision 44.

2. COLOSSUS 2A will use Comanche 44 as its starting base line for the program which they plan for use in the G mission. Candidate program changes suggested by MIT to be included in COLOSSUS 2A are as follows:

a. New ephemeris and stars

b. V82 time input

c. Backup Mark Button

d. Provide countdown to 0.5 g in P61.

e. Better definition of local vertical near sphere of influence where current formulation tends to break down.

f. Add PTC and Orbit Rate modes into DAP via extended verb.

g. Integrated stick during launch

h. V35 light test (?)

i. Lunar potential

j. P64 maximum G display

k. P34/35 speed up

l. Asteer

3. George Cherry also suggested a list of candidate of LUMINARY changes for post-G mission. They included:

a. Changes to the rendezvous braking phase to provide dis- play of raw rendezvous radar data and line-of-sight rates as well as providing some automatic line-of-sight attitude control.

b. Some rendezvous navigation improvements including updating W-matrix through maneuvers.

c. An improvement to the alignment programs to make it more convenient for the crew to align the LM IMU to the CSM IMU.

d. Explicit descent abort variable insertion targeting.

In general, spacecraft computer program development certainly seems to be under control with very little frantic activity foreseen. Probably the programs requiring the most attention now are associated with powered descent to the moon. In fact, Mr. Kraft had MIT give an informal briefing lasting about two hours in which they presented their opinion of how the descent targeting should be done. I gather it is in close agreement with things Floyd Bennett's people have been recommending.