Today was the scheduled liftoff day for the fifth X-37 mission (OTV-5), and the first aboard a Falcon 9. (X-37 was designed from the start to be compatible with almost any launch vehicle, including the Space Shuttle, but its first four launches were all aboard the Atlas V.) As a bonus, since SpaceX is still unable to use their original Florida launchpad, Cape Canaveral Air Station’s SLC-40, this launch used the pad they’re adapting for Falcon Heavy, Kennedy Space Center’s venerable LC-39A. So LC-39A got to launch another spaceplane after all. 😉 (LC-39A’s last spaceplane launch was STS-135, the final flight of the Space Shuttle program, just over six years ago.)
Coverage of the ascent stops with first stage separation, as normal for classified flights*, but since this was Falcon 9, we got to see coverage of the first stage continue all the way to touchdown back at the Cape. Now, SpaceX gets to scramble to safe it and stash it safely in a hangar in advance of Hurricane Irma.
*X-37 is not a classified spacecraft, but its missions are generally classified. This one does carry one unclassified payload, the Advanced Structurally Embedded Thermal Spreader, for the Air Force Research Laboratory. It will “test experimental electronics and oscillating heat pipe technologies in the long duration space environment”. Satellites already use heat pipe technology to draw waste heat away from sensitive electronic components (since obviously fans don’t work for cooling a spacecraft computer), but this new technology will be lighter and cheaper. All the other payloads, as well as their quantity and the target orbit and any planned maneuvers, remain classified. But they are probably also experimental technologies, since X-37 offers a unique opportunity to test equipment for a long duration in space and recover it for extensive engineering analysis afterwards.