Bit of a pen? Huh? I didn’t know what that meant, so I started digging.
It seems that one of the ascent engine circuit breakers was broken by either Aldrin or Armstrong as they were preparing for their moonwalk. Consensus seems to be, it was Aldrin’s fault. Moving around in a cramped Lunar Module wearing a bulky spacesuit ain’t easy. There was a bit of an argument over at CollectSpace as to whether the broken circuit was bypassed or if the pen was really used to complete the circuit. (In the process, they really slam Craig Nelson’s book “Rocket Men”, and I do agree with them that there are much better books about the Apollo program.)
From commenter faintgalaxy:
From 1968 to 2/1971 I worked as a tech for Mechanical Products Inc. in Jackson, MI. where we built the circuit breakers/switches used in the Apollo and LM space craft. I worked in the Engineering Lab where we basically hand built the breakers.
The evening of the breaking of the push-pull operating button, several techs were called into the Lab to determine how to safely reset the breaker. Once the breaker was reset they would not be able to reopen it without the pull button so they didn’t want to reset until it was needed for the assent.
We proceeded by breaking several breakers in the same manor as had occurred on the moon. We quickly determined the breakers could be reset by pressing in on the broken end of the button shaft with anything that would fit without affecting the calibration or normal function of the breaker.
That information was relayed to the astronauts “stuck” on the moon.
So now you know. Never underestimate the power of juryrigging.