The US’s mysterious space plane has come back to Earth – and still nobody will explain what it is for.
The craft, known as X-37B, has been in the sky since 2017.
When it dropped down at Nasa’s Kennedy Space Center over the weekend, it brought an end to the 780-day mission that is the longest ever carried out by the reusable vehicle.
The Air Force said the mission was a success and the craft had achieved its objectives, though not what those objectives are.
The X-37B has been on five such flights in the past.
1/10
The eye of Hurricane Dorian as captured by Nasa astronaut Nick Hague from onboard the International Space Station (ISS) on 3 September
Nasa/EPA
2/10
The River Nile and its delta captured at night from the ISS on 2 September
Nasa
3/10
The galaxy Messier 81, located in the northern constellation of Ursa Major, as seen by Nasa’s Spitzer Space Telescope
Nasa/JPL-Caltech
4/10
The flight path Soyuz MS-15 spacecraft is seen in this long exposure photograph as it launches from the Baikonur Cosmodrome in Kazakhstan on 25 September
Nasa/Bill Ingalls
5/10
Danielson Crater, an impact crater in the Arabia region of Mars, as captured by Nasa’s Mars Reconnaissance Orbiter spacecraft
Nasa/JPL-Caltech
6/10
A team rehearses landing and crew extraction from Boeing’s CST-100 Starliner, which will be used to carry humans to the International Space Station at the White Sands Missile Range outside Las Cruces, New Mexico
Nasa/Bill Ingalls
7/10
Bound for the International Space Station, the Soyuz MS-15 spacecraft launches from the Baikonur Cosmodrome in Kazakhstan on 25 September
Nasa/Bill Ingalls
8/10
Hurricane Dorian as seen from the ISS on 2 September
Nasa
9/10
A string of tropical cyclones streams across Earth’s northern hemisphere in this picture taken from the ISS on 4 September
Nasa
10/10
The city of New York as seen from the ISS on 11 September
Nasa
1/10
The eye of Hurricane Dorian as captured by Nasa astronaut Nick Hague from onboard the International Space Station (ISS) on 3 September
Nasa/EPA
2/10
The River Nile and its delta captured at night from the ISS on 2 September
Nasa
3/10
The galaxy Messier 81, located in the northern constellation of Ursa Major, as seen by Nasa’s Spitzer Space Telescope
Nasa/JPL-Caltech
4/10
The flight path Soyuz MS-15 spacecraft is seen in this long exposure photograph as it launches from the Baikonur Cosmodrome in Kazakhstan on 25 September
Nasa/Bill Ingalls
5/10
Danielson Crater, an impact crater in the Arabia region of Mars, as captured by Nasa’s Mars Reconnaissance Orbiter spacecraft
Nasa/JPL-Caltech
6/10
A team rehearses landing and crew extraction from Boeing’s CST-100 Starliner, which will be used to carry humans to the International Space Station at the White Sands Missile Range outside Las Cruces, New Mexico
Nasa/Bill Ingalls
7/10
Bound for the International Space Station, the Soyuz MS-15 spacecraft launches from the Baikonur Cosmodrome in Kazakhstan on 25 September
Nasa/Bill Ingalls
8/10
Hurricane Dorian as seen from the ISS on 2 September
Nasa
9/10
A string of tropical cyclones streams across Earth’s northern hemisphere in this picture taken from the ISS on 4 September
Nasa
10/10
The city of New York as seen from the ISS on 11 September
Nasa
The next is planned next year, when it will launch into space from Cape Canaveral.
“Each successive mission advances our nation’s space capabilities,” said Air Force secretary Barbara Barrett. But she, like everyone else involved wit the project, has not said what those capabilities are or what happens in those missions.
The X-37B looks like a space shuttle but it a quarter of the size, and is only 29 feet long.
It is launched on a rocket but then flies around above the Earth on its own, conducting work including experiments from the Air Force Research Laboratory.
