Alien hunters in frenzy over white UFO spotted in Nasa space shuttle launch footage

A MYSTERIOUS white UFO has been spotted in Nasa footage, sending alien enthusiasts into a frenzy.

The clip was filmed with a hand-held camera by one of the astronauts on board the space shuttle Endeavour after it blasted off on its final mission in May 2011.

It was uploaded to Nasa’s official YouTube channel at the time.

But UFO enthusiasts have now pointed out a mysterious object visible in the background.

The original clip shows the Endeavour’s extra fuel tank falling back towards Earth after being jettisoned just minutes after take-off.

But as it tumbles away, a white object flies past in the background.

UFO Today – a YouTube channel “dedicated to the UFO phenomena” – pointed the object out in its own version of the clip.

It said the object appears to fly along beneath the cloud line and estimates it to be bigger than the fuel tank falling towards it.

The channel speculates it could have discovered the “White Knight Satellite” – an apparent reference to a conspiracy theory about an extra-terrestrial spacecraft orbiting Earth.

Some alien enthusiasts claim the satellite – originally dubbed the Black Night – has been circling the planet for thousands of years after being sent from another world.

But UFO spotters changed the name after the latest apparent sighting to reflect the colour of what they think could be an “alien ship”.