WASHINGTON -- Billionaire Richard Branson’s Virgin Orbit reached space for the first time on Sunday with a successful test of its air-launched rocket, achieving a key milestone after aborting the rocket’s first test launch last year.

The Long Beach, California-based company’s LauncherOne rocket was dropped mid-air from the underside of a modified Boeing 747 nicknamed Cosmic Girl some 40,000 feet over the Pacific at 11:39 a.m. PT before lighting its NewtonThree engine to boost itself out of Earth’s atmosphere.

"According to telemetry, LauncherOne has reached orbit!" thecompany announced on Twitter during the test mission, dubbed Launch Demo 2. "In both a literal and figurative sense, this is miles beyond how far we reached in our first Launch Demo."

The rocket, a 70-foot launcher tailored for carrying small satellites to space, aimed to place 10 tiny satellites in orbit for NASA roughly two hours into the mission, though Virgin Orbit had not confirmed whether they were deployed as planned.

The successful test and potentially clean payload deployment would be a needed double-win for Virgin Orbit, which last year failed its attempt to reach space when LauncherOne’s main engine shut down prematurely moments after releasing from its carrier aircraft. The shortened mission generated key test data for the company, it said.

The Cosmic Girl carrier craft had taken off from an airstrip at the Mojave Air and Space Port in southern California under clear skies Sunday morning, bringing LauncherOne to its target altitude for launch.

The Launch Demo 2 mission was aimed at “enhancing our knowledge & demonstrating LauncherOne's full capabilities,” the company wrote on Twitter Sunday.

Virgin executives say high-altitude launches allow satellites to be placed in their intended orbit more efficiently and also minimize weather-related cancellations compared to more traditional rockets launched vertically from a ground pad.

Competition is fierce between Virgin Orbit, Firefly and U.S.-New Zealand company Rocket Lab, which are designing smaller or non-traditional systems to inject smaller satellites into orbit and meet growing demand.

Virgin Orbit’s government services subsidiary VOX Space LLC is selling launches using the system to the U.S. military, with a first mission slated for October under a $35 million U.S. Space Force contract for three missions.