US military’s mystery space plane rockets back into orbit

Full Screen
1 / 9

Boeing/USSF

This May 5, 2020 photo made available by the United States Space Force shows the X-37B Orbital Test Vehicle for the USSF at Cape Canaveral, Fla. The U.S. militarys mystery space plane rocketed into orbit again Sunday, May 17 this time with an extra load of science experiments. Its the sixth flight of an X-37B, a solar-powered plane that's flown by remote control without a crew. (Boeing/USSF via AP)

CAPE CANAVERAL, Fla. – The U.S. military’s mystery space plane rocketed into orbit again Sunday, this time with an extra load of science experiments.

It’s the sixth flight of an X-37B, a solar-powered plane that's flown by remote control without a crew.

Officials aren't saying how long the spacecraft will remain in orbit this time or the purpose of the mission. But a senior vice president for X-37B developer Boeing, Jim Chilton, noted each mission has been progressively longer.

The previous mission lasted a record two years, with a touchdown shrouded in darkness at NASA's Kennedy Space Center last year.

The winged spacecraft resembles NASA’s old shuttles, but is just one-quarter the size at 29 feet (9 meters) long. The one just launched features an extra compartment for experiments, including several for NASA and the U.S. Naval Research Laboratory, making it the biggest science load yet for an X-37B.

The Air Force has two of these reusable space planes. Their home base is a former space shuttle hangar at Kennedy.

“You could say that the X-37B stands on the shoulders of the space shuttle,” Chilton said. “From a common shape to a common home.”

Since the first flight in 2010, the secretive space planes had logged a combined 2,865 days in orbit as of Sunday.