LOS ANGELES—A Virgin Orbit rocket released from a jet flying off the California coast carried seven small satellites into space on Thursday as the company kicked off a year in which it plans to ramp up the pace of launches, including two originating from Britain. Virgin Orbit’s modified Boeing 747 took off from Mojave Air & Space Port in the Southern California desert, flew out over the Pacific Ocean, and dropped the LauncherOne rocket from its left wing. The 70-foot-long (21.3-meter) booster ignited at an altitude of about 35,000 feet (10,668 meters) and hurtled skyward. The company later confirmed that all of the satellites were successfully deployed into the proper orbit. “Another fantastic day for the Virgin Orbit team, and a big step forward for our customers,” the company tweeted. The payload included satellites for the U.S. Defense Department, the Polish company SatRevolution, and the international company Spire Global. It …