After separating from the command module in lunar orbit, the LM Antares had two serious problems. First, the LM computer began getting an ABORT signal from a faulty switch. NASA believed the computer might be getting erroneous readings like this if a tiny ball of solder had shaken loose and was floating between the switch and the contact, closing the circuit. The immediate solution – tapping on the panel next to the switch – did work briefly, but the circuit soon closed again. If the problem recurred after the descent engine fired, the computer would think the signal was real and would initiate an auto-abort, causing the ascent stage to separate from the descent stage and climb back into orbit. NASA and the software teams at the Massachusetts Institute of Technology scrambled to find a solution. The software was hard-wired, preventing it from being updated from the ground. The fix made it appear to the system that an abort had already happened, and it would ignore incoming automated signals to abort. This would not prevent the astronauts from piloting the ship, though if an abort became necessary, they might have to initiate it manually. Mitchell entered the changes with minutes to go until planned ignition.
After separating from the command module in lunar orbit, the LM Antares had two serious problems. First, the LM computer began getting an ABORT signal from a faulty switch. NASA believed the computer might be getting erroneous readings like this if a tiny ball of solder had shaken loose and was floating between the switch and the contact, closing the circuit. The immediate solution – tapping on the panel next to the switch – did work briefly, but the circuit soon closed again. If the prob.lem recurred after the descent engine fired, the computer would think the signal was real and would initiate an auto-abort, causing the ascent stage to separate from the descent stage and climb back into orbit. NASA and the software teams at the Massachusetts Institute of Technology scrambled to find a solution. The software was hard-wired, preventing it from being updated from the ground. The fix made it appear to the system that an abort had already happened, and it would ignore incoming automated signals to abort. This would not prevent the astronauts from piloting the ship, though if an abort became necessary, they might have to initiate it manually. Mitchell entered the changes with minutes to go until planned ignition.