Crews at Vandenberg Air Force Base are prepping for the landing of the second X-37B mini space shuttle after its approximately 15 months in orbit.
Landing of the Air Force’s unmanned, reusable spaceplane on Vandenberg’s 3 mile-long runway is expected to occur in early to mid-June, officials said Wednesday.
Air Force officials said the exact landing date and time will depend on technical and weather considerations.
A 48-hour announcement of the landing is expected, since the Air Force must advise mariners and aviators to stay out of the area due to the impending landing.
The X-37B Orbital Test Vehicle launched March 5, 2011 from Cape Canaveral Air Force Station, Fla., for a top-secret mission in orbit.
The vehicle is designed for a 270-day mission, but officials have said since the launch that X-37B could remain in orbit much longer than nine months.
“We’re incredibly happy with the way the mission has gone,” said Maj. Tracy Bunko, an Air Force spokeswoman at the Pentagon.
She noted the vehicle has been in orbit for more than 400 days.
“We’re extremely pleased with the status of the vehicle and the feedback we’ve gotten from the mission,” she added.
Program officials are eager to see how the X-37B’s thermal protection system performed after being in space twice as long as it was designed for.
“I’m sure we’ll learn more from this one when we get it back,” Bunko said.
The specific mission remains top secret, with Air Force officials only saying the experimental vehicle is testing technology on board.
“Primarily we’re testing the vehicle itself, the vehicle’s ability to stay on orbit, to deorbit and land. The vehicle itself is a huge experiment,” said Bunko.
However, space hobbyists tracking the vehicle as it circles Earth say X-37B has appeared in an orbit that is typical of top-secret imaging satellites.
Air Force officials said the cost of the mission is classified.
Since the launch, Vandenberg crews have conducted extensive, periodic training in preparation for landing, officials said.
The first X-37B spent about 224 days orbiting Earth before landing in December 2010, marking the first reusable vehicle to land on Vandenberg’s runway. The autonomous vehicle touched down at night before it glided to a stop.
Because the first vehicle suffered tire damage upon touching down, Vandenberg’s airfield managers and engineers conducted a thorough runway inspection in the months after the landing.
The inspection revealed 141 small imperfections — minor concrete irregularities that could affect the X-37B’s small, thin-walled tires. Earlier this year, crews completed grinding down the imperfections to try to avoid damaging the vehicles tires upon landing.
The first X-37B vehicle will head to space for its second mission this fall.
“One of the technologies we’re trying to demonstrate is reusability,” Bunko said.