The past and future of America’s space arsenal intersected, briefly, in the summer of 2011. For two weeks in July, NASA’s Space Shuttle Atlantis roughly shared its Earth orbit with the Air Force’s X-37B, a 29-foot-long, highly maneuverable robotic spacecraft that entered service in early 2010 and has been cloaked in secrecy ever since. The X-37 was around 80 miles higher than the Shuttle, so it’s doubtful the four-person Atlantis crew, conducting the 135th and last Shuttle mission, ever saw the robotic craft. The X-37′s small size — barely a quarter the length of Atlantis — made a sighting even less likely.
Equally striking was the difference in cost between Atlantis and its tiny robotic compatriot. Atlantis cost more than $10 billion to design and build and around $500 million to launch on that one mission. The Boeing-built X-37 mini-shuttle set the taxpayers back an estimated $1 billion for development and construction and just $180 million to send into space. (All cost figures in this story are in today’s dollars.)
There are lots of things Atlantis could do that the X-37 cannot and vice versa, complicating any direct comparison. Both craft were designed to carry scientific and military payloads into orbit: Atlantis, with its school-bus-size cargo bay, emphasized carrying capacity; the X-37, optimized for endurance, has a bay the size of a pickup truck’s bed. Still, it’s almost unheard of for a major government technology to be cheaper than its immediate predecessor. Just ask the Air Force, with its $400 million F-22 fighters replacing F-15s that cost a quarter as much.
Moreover, the X-37B is meant to be launched into space on short notice, remain in orbit for a year or more and return only when its fuel tanks finally run dry. After a few weeks or months of reconditioning, the mini-shuttle is ready to return to space atop an Atlas rocket. With its fleet of two X-37s, the Air Force can keep at least one in orbit at all times.
Because they had to support their human crews, Atlantis and her sister Space Shuttles could spend at most two weeks in orbit before their water and air supplies began to run out. Between flights the manned orbiters needed nine months of expensive reconditioning by Rockwell, the main Shuttle contractor. It would have taken a fleet of 18 Space Shuttles to ensure one was in space at all times, but NASA built only five of the massive spacecraft for a total program cost of more than $200 billion.