The US military has launched its secret space plane on another mission, which is expected to last at least two years
The US military's X-37B space plane blasted off Thursday on another secret mission that is expected to last at least two years.
As with previous missions, the mini space shuttle-like reusable aircraft carried out classified experiments. No one was on board.
The space shuttle's late-night liftoff from NASA's Kennedy Space Center was delayed more than two weeks due to technical issues with SpaceX's Falcon Heavy rocket.
This marked the seventh flight of the X-37B, which has logged more than 10 years in orbit since its debut in 2010.
The last flight, even longer, lasted 2 1/2 years before ending up on the runway at Kennedy a year ago.
Space Force officials would not say how long the orbiting test vehicle would remain aloft or what it was other than a NASA experiment to measure the effects of radiation on objects.
Developed by Boeing, the X-37B resembles NASA's retired space shuttles. But they are only a quarter of the length of 29 feet (9 meters). Astronauts are not needed; The X-37B has an autonomous landing system.
They take off vertically like rockets but land horizontally like airplanes, and are designed to orbit at altitudes between 150 miles and 500 miles (240 kilometers and 800 kilometers). Kennedy has two X-37Bs in a former shuttle hangar.
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