The rocket flew a group of tiny satellites on behalf of NASA's Educational Launch of Nanosatellites, or ELaNa, program, which allows high school and college students to design and assemble small satellites that NASA then pays to launch into space.
"A new gateway to space has just sprung open!"
When it reaches the required altitude, the plane releases the rocket, whose own engine fires up to push it into Earth's orbit and places its payload in space.
The launch happened on Sunday morning around 10:50 AM PT (13:30 PM EST) from California's Mojave Desert, and saw Cosmic Girl part ways from the rocket at approximately 35,000 feet (10,500 meters) in the air. Virgin Orbit conducted several "drop tests" of its LauncherOne rocket, which involved flying the vehicle out over the Pacific and letting it plunge into the ocean to vet the 747's release mechanism.
"Everyone on the team who is not in mission control right now is going absolutely bonkers", Virgin Orbit tweeted. Virgin Orbit also offers something very different from current launch providers like SpaceX, which typically serves larger payloads or which must offer rideshare model missions for those with smaller spacecraft.
Cosmic Girl had already flown more than 8,000 flights, carrying about 2.5 million passengers, since it was first procured by Virgin Atlantic in 2001. Sir Richard Branson's company is hoping to become a player in the market for lower-cost satellite launches.
"Virgin Orbit has achieved something many thought impossible", Branson added, calling it "the culmination of many years of hard work".
Virgin Orbit had expected to try a second orbital launch attempt in late 2020, but the company was forced to postpone after "a few" of its employees tested positive for Covid-19, according to an email from the company.