Buzz Aldrin’s felt-tipped pen came in handy at a crucial time.

With the 50th anniversary of the first manned moon landing this week, a little known story about how a simple stationery item saved the mission has emerged.

Astronauts Buzz Aldrin and Neil Armstrong were seconds away from never returning back to earth after one of Apollo 11’s most important switches broke.

The circuit breaker that activated the ascent engine, getting them off the moon, had broken - so Aldrin decided to think outside the box and use a felt-tip pen to flick the switch instead.

If it doesn’t work, or the ascent engine fails, they have no hope of rescue.

The felt-tip pen works, Eagle’s ascent engine fires, explosive bolts release the ascent stage section from the landing gear and a guillotine severs power cables between the two.

Clouds of dust surround the lunar module as it lifts off, leaving the legs on the surface of the moon. Aldrin sees the American flag fall over. Back on Earth, their families cry with relief.