LOS ANGELES—Richard Branson’s Virgin Orbit reached space on Sunday, eight months after the first demonstration flight of its air-launched rocket system failed, the company said. A 70-foot-long LauncherOne rocket was released from beneath the wing of a Boeing 747 carrier aircraft off the coast of Southern California, ignited moments later and soared toward space. The two-stage rocket carried a cluster of very small satellites known as CubeSats developed and built as part of a NASA educational program involving U.S. universities. The launch occurred after the Boeing 747-400 took off from Mojave Air and Space Port in the desert north of Los Angeles and flew out over the Pacific Ocean to a drop point beyond the Channel Islands. “According to telemetry, LauncherOne has reached orbit!” Virgin Orbit tweeted later. “Everyone on the team who is not in mission control right now is going absolutely bonkers.” The rocket’s upper stage coasted for …