Photos: More shots of Delta 4 liftoff

Nearly a decade in the making, NASA and SpaceX have set May 27 as the target launch date for the first crewed space mission to launch into orbit from U.S. soil since the retirement of the space shuttle in 2011.

The Air Force will launch a second pair of small security probes 22,300 miles above the Earth using a Delta 4 rocket on Friday to alert ground controllers of impending space collisions and monitor potential meddling with U.S. orbiting assets.

SpaceX and its visionary founder Elon Musk win the lion’s share of public attention in the commercial rocket arena, with dramatic, increasingly routine booster landings and spectacular stunts like the launch of Musk’s Tesla Roadster on the maiden flight of the company’s new Falcon Heavy rocket last month.