LauncherOne
A retired rocket that was carried under the wing of a Boeing 747 and launched in mid-air. It ended with Virgin Orbit's 2023 bankruptcy.
Why it matters
Air launch promised flexible launch sites anywhere a jumbo jet could take off. LauncherOne put 33 satellites into orbit, but Virgin Orbit could not raise enough money to keep operating.
How the technology works
A modified Boeing 747-400, Cosmic Girl, carried the rocket aloft and released it, and the rocket then ignited and flew to orbit. Because the carrier is an aircraft, the company could fly from locations around the world instead of a fixed launch pad.