With the performance hit on the Atlas 5 rocket’s most recent flight last month now isolated to a faulty valve, preparations to resume the manifest are underway as United Launch Alliance workers stack the next booster for blastoff this summer.

A United Launch Alliance Atlas 5 rocket put on a display of power, sound and light Friday evening at Vandenberg Air Force Base in launching a clandestine national security payload, then successfully debuted a new upper stage engine as it flew over the horizon.

Virgin Orbit could attempt its first orbital test launch later this month over the Pacific Ocean southwest of Los Angeles, capping a development program for an air-launched small satellite carrier that began in earnest eight years ago.