The US Air Force has two X-37B space planes, and since 2010 each of them have flown two missions into outer space. Those flights have ranged in length from 224 to 717 days.
For the first four missions, the Boeing-developed space plane has launched on top of an Atlas V rocket, the military's go-to vehicle manufactured by United Launch Alliance. However, on Tuesday during a meeting of the US Senate Armed Services Committee, Air Force Secretary Heather Wilson revealed that the upcoming fifth mission of the X-37B will be launched into space by a Falcon 9 rocket. That SpaceX launch is tentatively scheduled for August.
Wilson testified that the emergence of the commercial space industry has proven a boon for the US military. "The benefit we're seeing now is competition," she said. "There are some very exciting things happening in commercial space that bring the opportunity for assured access to space at a very competitive price."
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