US military launches secret space plane to fly around the Earth for years

The US military has launched a secretive space plane on a years-long mission.

It is the seventh flight for the X-37B , which first launched in 2010 and has spent more than 10 years in orbit since. It does not carry any crew.

But the US government has kept almost all of the space planes operations secret. It says only that it is a “experimental test program” that is testing out new technologies.

This mission includes tests such as “operating the reusable spaceplane in new orbital regimes, experimenting with future space domain awareness technologies”, the Space Force said in a statement last month. The latest experimental launch would “expand the United States Space Force’s knowledge of the space environment by experimenting with future space domain awareness technologies”, it said in a typically vague description that nonetheless said the experiments would be “groundbreaking”.

The lack of information about the space plane’s missions has led to rampant speculation about what those secret activities might be, including testing for spy sensors and surveillance on other country’s satellites.

The spacecraft blasted off on Thursday on board a SpaceX Falcon Heavy rocket from Nasa ’s Kennedy Space Center. The launch had been repeatedly delayed because of bad weather and technical issues.

The last flight, the longest one yet, lasted 2 1/2 years before ending on a runway at Kennedy a year ago.

Space Force officials would not say how long this orbital test vehicle would remain aloft or what's on board other than a Nasa experiment to gauge the effects of radiation on materials.

Built by Boeing , the X-37B resembles Nasa’s retired space shuttles. But they're just one-fourth the size at 29 feet (9 meters) long. No astronauts are needed because the X-37B has an autonomous landing system.

They take off vertically like rockets but land horizontally like planes, and are designed to orbit between 150 miles and 500 miles (240 kilometers and 800 kilometers) high. There are two X-37Bs based in a former shuttle hangar at Kennedy.

Additional reporting by agencies