Thursday, February 5, 2009

Antares on the Moon

Apollo 14's LM, Antares, landed at Fra Mauro on February 5, 1971. It seemed doubtful for a while that the landing would happen. A loose piece of solder in a switch kept signaling an 'abort' condition. Even though everyone knew it was a small and intermittent hardware problem, there was concern that the flight computer would get the erroneous signal during powered descent and abort the landing. MIT software engineers hastily wrote a patch to work around the condition. They radioed it up and Ed Mitchell, LM Pilot, entered the changed software by hand on the DSKY keypad.

Unfortunately, the software patch contained a bug which caused the landing radar not to lock on. Flight rules called for an abort if the radar did not lock on. Mitchell reset the circuit breaker, and that did the trick. There was a lot of speculation later on as to whether Shepard, intent on making a Moon landing, would have proceeded with the landing even without the radar. As it was, he made the closest landing to the designated landing spot of any of the Apollo commanders.

So, this was yet another nail-biter to listen to as we followed the TV coverage. Pete Conrad and Al Bean in Apollo 12 had the only trouble-free touchdown to this point.

I'm looking forward to meeting Ed Mitchell at Spacefest in San Diego in two weeks! I can't wait to hear from him what it was like to work with Al Shepard in such close quarters. I can only imagine that one would have to give Shepard plenty of leeway.

This booklet, "Science at Fra Mauro," was put out by NASA shortly after the mission ended. I picked up this copy at NASA Headquarters Office of Public Affairs in June 1971.

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