‘One small step’: Spider, the crew-named lunar module of Apollo 9, was the first spacecraft that was unable to return to Earth. Due to circumstances beyond NASA’s control, the astronaut who was supposed to pilot the lunar module died on an earlier mission. This meant that back up crews had to be rotated, which put Neil Armstrong and Buzz Aldrin in the prime position of being the astronauts to be the first to walk on the Moon in July of 1969.