Richard Branson's Virgin Orbit on Wednesday released a rocket from the wing of a modified Boeing 747 jetliner in midair in a key test of its high-altitude launch system for satellites, the company said.

In the penultimate mission before Virgin Orbit offers commercial satellite launch services, likely before year's end, the 70-foot (21.34-meter) LauncherOne rocket cleanly separated from the jetliner.

The rocket, loaded with water and antifreeze to simulate the weight of fuel, was set to crash as planned in the Mojave Desert as the jetliner, nicknamed Cosmic Girl, continued on its flight path.