SpaceX launched a classified payload for the National Reconnaissance Office on Monday after a first stage sensor problem halted a countdown Sunday. Liftoff from launch pad 39A at NASA’s Kennedy Space Center in Florida occurred at 7:15 a.m. EDT (1115 GMT), and the first stage landed at nearby Cape Canaveral around nine minutes later. The upper stage’s flight entered a pre-planned news blackout a few minutes after launch.

The Orion spacecraft slated to fly around the moon on an unpiloted mission next year has arrived back at the Kennedy Space Center following an environmental test campaign in Ohio, ready for a series of final checkouts before officials pause launch preparations this summer to await readiness of NASA’s Space Launch System.

A little more than a year after the Falcon Heavy rocket’s first test flight, SpaceX teams on Florida’s Space Coast are readying the world’s most powerful operational launcher for its second mission Thursday with a commercial communications satellite.