Photos: Delta 4 powers from launch pad on military mission

The mission, dubbed Cert-2 by United Launch Alliance, is the final mission required before the rocket can begin launching national security missions. Liftoff is set for the beginning of a three-hour window at 6 a.m. EDT (1000 UTC).

SpaceX founder Elon Musk said this weekend that the company is about one month away from launching the first Crew Dragon spacecraft on an unpiloted test flight to the International Space Station, a precursor to a demonstration launch with astronauts later this year. He also warned that early test flights of the commercial crew capsule, built under contract to NASA, will be “especially dangerous.”

The United Launch Alliance Delta 2 was launched Saturday at 6:22 a.m. local time with NASA’s Soil Moisture Active Passive (SMAP) satellite from Vandenberg Air Force Base in California.