Live coverage: Atlas 5 countdown and launch journal

In a breath-taking display at daybreak Wednesday, an Atlas rocket powered an enormous U.S. Navy satellite into space to close the last remaining gap and give global reach to the military’s new mobile communications system.

Liftoff of a previously-flown Falcon 9 rocket is set for 6:27 p.m. EDT (2227 GMT) Thursday from NASA’s Kennedy Space Center in Florida, the first time SpaceX has reused one of its first stage boosters on a second mission. Ground crews face a tight timeline to ready the rocket and the SES 10 communications satellite in time for a Thursday launch attempt.

NASA officials have determined that the robotic InSight lander is ready for its mission to Mars after concluding that the probe should not suffer the same flaw that led to a crack in a heat shield undergoing tests for the space agency’s Mars 2020 rover, InSight’s chief scientist said Monday.