Live coverage: SpaceX launches another batch of Starlink satellites

United Launch Alliance called off the planned liftoff of a Delta 4-Heavy rocket and a classified National Reconnaissance Office spy satellite from Vandenberg Air Force Base in California on Wednesday after indications of elevated hydrogen concentrations around one of the launcher’s main engines. Three previous launch attempts were scrubbed by technical concerns and bad weather.

The mission is one of two Starlink flights scheduled to fly from Florida within a four-hour window of opportunity. Liftoff of the Starlink 6-85 mission from pad 40 at Cape Canaveral Space Force Station is scheduled for 1:44 a.m. EST (0644 UTC).

The United Launch Alliance Atlas 5 rocket, standing 189 feet tall and and weighing 840,000 pounds, unleashes 1.2 million pounds of thrust from its main engine and one side-mounted booster at 7:05 p.m. EDT (2305 GMT) today to launch NASA’s OSIRIS-REx mission to Asteroid Bennu.