Now we know where the X-37B is. Amateur sky-watchers have spotted the Air Force miniature space plane traveling in low-earth orbit at an inclination that takes it over Iraq and Afghanistan, among other nations.
But this big question remains: What the heck is the X-37B doing up there, anyway?
The Air Force isn’t saying. It’s secret. “The actual on-orbit activities we do classify,” said Gary Payton, Air Force Undersecretary for Space Programs, during a conference call with reporters in late April.
On April 22 an Atlas V rocket roared into the sky from Cape Canaveral, Fla., carrying the X-37B on its first orbital test flight. At that moment the reusable craft vanished, as far as the general public was concerned. The Air Force did not say where in space the X-37B was going.
But last week a team of sky-watchers with members who specialize in tracking orbiting objects announced that they’ve spotted what they are certain is the X-37B in space, about 255 miles up, circling the earth every 90 minutes.
The X-37B is traveling in a an area bounded by 40 degrees north latitude (the mid-Atlantic of the US, Spain, the Middle East) and 40 degrees south latitude (Argentina, South Africa, Australia), according to Greg Roberts, a South African member of the spotting team.
The Air Force says that the performance of the system itself is the biggest thing this launch is testing. They want to see how the X-37B performs in orbit, how it flies itself back to the ground, and how quickly they can get it ready to re-launch. The goal is to be able to turn the X-37B around as fast as the Air Force could turn around a high-performance spy plane such as the SR-71 Blackbird.
“That’s [a time period] measured in several days, or maybe 10, 15 days or less, something like that,” said Mr. Payton in April.
But an Atlas V launch, combined with weeks in space, is awfully expensive just to test the X-37B. The spacecraft surely will have another purpose, and it’s likely the Air Force is currently testing the system’s performance in that unknown capacity, as well.
Brian Weedan, a former Air Force missile officer who is currently a technical advisor on space issues at the Secure World Foundation, has compiled a list of possible missions for the X-37B. Beginning with roles that are most likely, and moving through those that are less so, it runs like this:
SENSOR TESTER. Almost certainly the X-37B is carrying sensors that are either being used on current US spy satellites, or are being evaluated for future use. These could include space-based radar, optical spy sensors, and signals eavesdropping equipment. A reusable space plane would be a handy test bed to measure the performance of stuff that has work as advertised once it is in orbit on a satellite.
SATELLITE DEPLOYER. The X-37B, like the Space Shuttle, has a cargo bay that opens up, making it possible for the vehicle to serve as a sort of glorified pick-up truck that carries satellites into space and then kicks them out into orbit. The Air Force’s Payton noted in April that the system was capable of carrying two satellites that weigh several hundred kilograms each.
REPAIR VAN. The X-37B might be able to rendezvous with malfunctioning satellites, grab them with a crane arm, load them in its cargo bay, and bring them back to earth for refurbishment. Spy satellites can be expensive and delicate, so such a capability could be important to the US. However, as Mr. Weedon of the Secure World Foundation notes, the X-37B’s orbital height is limited, and the actual rendezvous with any broken satellite could be tricky.
WEAPON. Though many critics have worried that the X-37B might be a step towards the weaponization of space, the chance that it is a strike weapon itself are close to “zero,” according to Weedon. While it could be steered to hit almost any area on earth, it glides slowly to a landing, traveling in a straight line, and thus would be easy to shoot down.