Live coverage: Kennedy Space Center to reopen Friday

United Launch Alliance said Monday it did not submit a proposal in a competition to launch a U.S. Air Force GPS navigation satellite, apparently relinquishing the contract to rival SpaceX, the only other company certified to launch the mission.

NASA’s ICESat 2 satellite has been bolted atop a United Launch Alliance Delta 2 rocket at Vandenberg Air Force Base in California as ground teams prepare for the final liftoff of the workhorse launcher Sept. 15.

Rollout of the Atlas 5 rocket from the Vertical Integration Facility to the launch pad at Complex 41 occurred at 10 a.m. on Monday. Liftoff is planned for Tuesday night to deliver the Cygnus resupply ship into orbit en route to the International Space Station.