Tom Jones, a veteran of four space shuttle missions over 11 years, who pondered the mystery of alien crafts before joining the US space agency, says he can solve once and for all the mystery of the so-called "UFO Tether Incident" of 1996.

The story involved a satellite, which was tethered to the space shuttle, breaking off.

When it was later filmed by the astronauts on board, it appeared to be swarmed by hundreds of UFOs appearing like organisms swimming in a sea, according to onlookers.

But conspiracy theorists will be unsatisfied with Mr Jones ‘conclusive proof of’ what the stunning sight was.

In an Ask the Astronaut column for Smithsonian Air & Space Magazine he discusses the age-old question of whether he or other astronauts had seen real alien space craft while in orbit.

According to conspiracy theorists there are scores of NASA astronauts and personnel who have seen evidence of UFOs and aliens, some who have blown the whistle, and others who remain tightlipped for fear of what will happen.