Live coverage: Intelsat’s first “Epic” satellite in orbit after Ariane 5 launch

Four veteran astronauts have been selected to train for launch aboard new commercial crew capsules being built by Boeing and SpaceX that are intended to ferry astronauts to and from the International Space Station starting in 2017, NASA announced Thursday.

The 330-foot tall mobile service tower is rolled away from the United Launch Alliance Delta 4 rocket at Cape Canaveral’s pad 37B in the hours before the scheduled liftoff on Dec. 7 at 6:53 p.m. EST (2353 GMT).

NASA has purchased two seats on Russian Soyuz capsules launching later this year and in early 2018 to expand the crew on the U.S. segment of the International Space Station from three to four, and reserved options to fly astronauts on Soyuz spacecraft in 2019 if commercial rides are not available in time.