When I last posted on the amazing journeys of Apollo 17, astronauts Gene Cernan and Jack Schmitt had just left the lunar surface in LM Challenger to rendezvous with Ron Evans and the CSM America. I had intended to write a summary of the lunar and planetary science experiments that the mission executed from lunar orbit, but the events of Friday put me out of the mood.
A good rundown of the lunar science experiments carried aboard America during Apollo 17’s time in lunar orbit can be found at the website of the Lunar and Planetary Institute. The orbital experiments were predominately contained in the Scientific Instrumentation Module (SIM) contained in the Service Module of the CSM spacecraft. A SIM was also included on both Apollo 15 and Apollo 16.
As Apollo 17 was going to be the last manned mission to the Moon for some time (little was it known then for how long) the astronauts spent more time in lunar orbit – over six days – than any other Apollo mission.
|Good view of America‘s SIM package, taken from LM Challenger|
At 236:42:09 Ground Elapsed Time (GET), 6:35PM EST, December 16, 1972, America‘s SPS engine fired up for Trans-Earth Injection (TEI) on orbit from the far side of the Moon. The burn ended after a few minutes, and the last three humans to see the Moon up close and personal were on their way home.
About 21 hours later, the crew had one last risky task to accomplish before their harrowing and fiery plunge back into Earth’s atmosphere – a deep space EVA. The cameras and instruments back in the Service Module’s SIM bay had to have their data retrieved, and it was up to Command Module Pilot Ron Evans to spacewalk back there and get them. All three astronauts suited up, depressurized America, and got to work at 3:27PM on December 17..
Note the EVA handrails in the pictures that Evans used to stabilize himself. The spacewalk was a complete success, and lasted slightly more than an hour.
Flight day 11, December 18, 1972 (forty years ago today) was an uneventful one during the trans-Earth coast. Beyond normal spacecraft housekeeping, the last men to voyage to the Moon didn’t have anything to do.
Please return tomorrow to mark the anniversary of the last lunar voyagers’ return to their home, and for my commentary on the meaning of Apollo.