If all goes well, Peregrine would mark the first U.S. soft landing on the moon since the final Apollo landing in 1972, and the first-ever lunar landing by a private company - a feat that has proved elusive in recent years.

The launch was a crucial first for ULA, which developed Vulcan to replace its workhorse Atlas V rocket and rival the reusable Falcon 9 from Elon Musk's SpaceX in the satellite launch market.