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Inspections have begun on Air Force space plane

Posted: December 12, 2010

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U.S. Air Force and Boeing Co. engineers will thoroughly review the performance of the first X-37B space plane before committing to launching a duplicate vehicle in the spring of 2011, according to Pentagon officials.

Footage of the landing and post-flight safing of the X-37B space plane. Credit: U.S. Air Force
Wrapping up a secret mission in orbit, the unmanned spacecraft glided back to Earth Dec. 3 and made a pinpoint landing on a 15,000-foot-long runway at Vandenberg Air Force Base, Calif.

The space plane, also called the Orbital Test Vehicle, launched April 22 on a conventional expendable Atlas 5 rocket and circled Earth for nearly 225 days, but much of its activities the last eight months are classified. The Air Force says the flight was focused on proving the craft could operate in space and survive a fiery return to the ground.

"You've got to imagine that this vehicle took off on an Atlas 5, operated in space, and then autonomously was commanded to reenter, flew down its track, and then landed exactly where we wanted it to, and all without any assistance," said Richard McKinney, deputy under secretary of the Air Force for space programs. "It was all autonomous. That's a tremendous accomplishment of the team."

For a team of Air Force and Boeing engineers, the work is just getting started.

A few hours after landing, recovery crews towed the 29-foot-long space plane to the Astrotech satellite processing facility at Vandenberg. Engineers are inspecting the X-37B to collect data on how the craft weathered its time in space.

The mission set several records, including the longest duration flight of a known winged spacecraft and the first automated reentry and runway landing ever accomplished by the U.S. space program.

Boeing is building a second OTV at a factory in Southern California. The spacecraft will be shipped "soon" to prepare for launch at Cape Canaveral, Fla, McKinney said. Like the first mission, the next space plane will also blast off on an Atlas 5 rocket.

The flight was scheduled for launch March 4, but McKinney would not publicize a specific date until completing post-mission reviews of the first mission.

"It's really just a matter of months before we do our next flight," McKinney told reporters last week.

"Before we get there we've got to examine this vehicle that just landed and see if there's anything in there that would (tell us) we're not ready to go launch yet," McKinney said. "I think that's why we're not telling you exactly when we're going to go, because frankly, we want to make sure we examine this other vehicle and make sure everything's OK, and then we'll be able to proceed."

The OTV launch is the next scheduled flight of an Atlas 5 rocket.

Officials revealed several findings following a first glance at the vehicle after landing.

The X-37B on the Vandenberg runway after landing. Credit: U.S. Air Force
McKinney said the X-37B's left tire blew out as the space plane rolled out after touchdown.

The craft's main landing gear tires are about the size of a dinner plate and normally pressurized to about 300 psi. Engineers believe the X-37B may have struck something on the runway to cause the tire failure, but that's just an early hypothesis, according to McKinney.

In the first few days after landing, inspections revealed about seven locations of damage from space debris. But some of the dings could be from the tire blowout as shredded pieces of the landing gear struck the bottom side of the space plane, McKinney said.

"I think as we get the data and we analyze it we'll release it," McKinney said.

Lt. Col. Troy Giese, the Air Force's X-37B program manager, said the space plane's first flight was a complete success.

"The vehicle did perform everything that it was asked to on this particular flight," Giese said. "We look forward on the second flight to basically expanding the operational envelope of what the capabilities are."

The next flight will take the X-37B one step further to prove it can operate under a wider range of conditions.

"We put some more strict restrictions on the landing winds on this first flight compared to what the design is," Giese said. "So there are things like the winds and even de-orbit cross-range. We picked an orbit that we knew was well within our capabilities to get to Vandenberg. So some of the things that we could look at doing is expanding or proving out that capability for more of a reentry cross-range, or even weather conditions themselves."

The X-37B flew back to Earth on autopilot, executing a series of banking turns to bleed off speed as it plunged back into the atmosphere at ten times the velocity of a rifle bullet.

Then the space plane lined up with the runway with the aid of GPS navigation, dived toward the landing site, deployed its landing gear and touched down at nearly 300 mph.

The recovery team tows the X-37B to the Astrotech processing facility at Vandenberg. Credit: U.S. Air Force
"We got lucky in that there was no precipitation or heavy fog," Giese said. "The tiles are designed to be able to, that's one of the improvements from the shuttle days, is to withstand a little heavier in-atmosphere precipitation. So that's another thing we can look at for this next flight."

The X-37B's heat shield includes a mix of thermal blankets and tiles made of silica and ceramic material.

Air Force officials revealed little about what experiments and payloads this or future X-37B missions could carry into space.

Managed by the Air Force Rapid Capabilities Office in the Pentagon, the program's cost is secret.

"We're going to use this to put experiments on orbit," McKinney said. "We're going to check them out. We're going to test them and we're going to bring them back. That's what this is."

According to McKinney, unclassified applications for the X-37B could include communications, weather observation, navigation and materials technologies. But those are just hypothetical uses, McKinney said.

"Let's just say we have a new weather satellite with a new sensor that allows us to tell us soil moisture on the ground," McKinney said. "It would be nice to know if that new technology works, so this would allow us to put it up there, check it out, and if it didn't work out perfectly we'd have a chance to examine it."

The OTV program's future beyond the next flight is unclear.

"This is kind of a crawl, walk, run type thing," McKinney said. "We're still proving out this capability. As we get more information, more data, then we'll make a determination of is this an effective tool? Is there value on going one step further?"