They call them ‘chase planes’. They’re a fleet of fighter aircraft of the type usually operated by the US Air Force, Navy and Marine Corps. But these fast jets have a different mission – helping turn pilots into astronauts, and keeping a watchful eye on Nasa’s spacecraft and experimental aircraft.

The video you see here, released on 27 May, shows the pilot of an F-15D Eagle fighter manoeuvring behind a KC-135 tanker; pilots are trained to use these ‘aerial petrol stations’ to top up their fuel tanks on long-range missions.