Monday, February 16, 2009

Prepping for a mission

Among the artifacts that I have most enjoyed collecting over the years are items that were used by astronauts or mission support teams in the endless planning and practicing that preceded missions.

This training manual belonged to Dave Scott, who later commanded the Apollo 15 mission to Hadley Rille. The manual predates the Apollo 15 training, however. It was issued to Scott in February 1970, before even the Apollo 13 mission. In fact, it was for an "H mission," using the same types of LMs as Apollos 11-14. In these missions, the LM's powered descent started from a 60-mile orbit, and there was no lunar rover. The "J missions," Apollos 15-17, had an extended duration LM, used the lunar rovers, and used the Command/Service Module to take the LM down to 50,000 feet before turning the LM loose to land on its own. Moving down to the lower altitude using the CSM gave the heavier J-mission LMs more fuel for the critical last minutes of landing.

Scott annotated this manual heavily. It's fascinating to see what he chose to concentrate on in learning the techniques for lunar descent. For example, Scott has underlined a section that says, "If the LR [landing radar] altitude data-good signal has not been received by a PGCNS [guidance system] indicated altitude of 10,000 feet, the crew will abort." This is precisely the scenario that was mentioned in my recent post about Apollo 14 [a year after this manual was written], where the lack of landing radar data almost caused the crew to abort the landing, until it was corrected at the last possible moment.