It’s a story that for many years was not circulated outside the inner circles of the U.S. Space Program: The Fisher Space Pen helped the original Moon-landing astronauts, Neil Armstrong, and Edwin (Buzz) Aldrin get back to Earth.
When about to leave the moon, the astronauts were climbing back into the Lunar Module and the life support backpack on one of the astronauts brushed against the plastic arming switch and broke it. The switch was to be used to activate the Lunar Modules engines for the module’s rendezvous with the mother spacecraft.
Aldrin informed Houston’s Space Centre by radio. A scientist immediately went to work on the problem by breaking the plastic switch on a duplicate module and studying the possibility of reaching a tiny metal strip inside the switch. The strip had to be flipped over to one side to activate the Lunar Module engine, but ground control knew the astronauts had dispensed with practically every tool in the interest of less weight. But they still had their Space Pens, and so were advised to retract the point and use the hollow end of the pen to activate the inside switch. Aldrin then used his Space Pen to flick the switch, lifting Neil Armstrong and Buzz Aldrin safely off the moon!