United Launch Alliance’s Delta 4-Heavy rocket lifted off at 11:10 a.m. PST (2:10 p.m. EST; 1910 GMT) Saturday from Vandenberg Air Force Base, California, after a month-long delay to troubleshoot a hydrogen leak in one of its boosters. The heavy-lifter was on a mission to send a U.S. government spy satellite into orbit.
The first of up to seven missions planned on United Launch Alliance’s Atlas and Delta rocket fleets this year is scheduled for Saturday from California’s Central Coast, when a Delta 4-Heavy is set for blastoff on a spy satellite delivery flight delayed a month to troubleshoot a hydrogen fuel leak in a booster.
After unusual concentrations of hydrogen around the rocket foiled a launch attempt Dec. 19, United Launch Alliance said Friday that the company’s powerful Delta 4-Heavy launcher and a U.S. government spy satellite will remain grounded in California until at least Jan. 6 as engineers troubleshoot a small fuel leak.
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.