Live coverage: Atlas 5 countdown and launch journal

Prognosticators are predicting favorable weather conditions to launch an Atlas 5 rocket Thursday and send NASA’s OSIRIS-REx spacecraft on its interplanetary journey to interrogate an asteroid and collect a surface sample for return to Earth.

Rocket Lab’s first launch of the year lifted off Thursday at 7:27 p.m. EDT (2327 GMT) after a four-day delay to replace a video transmitter and wait for improved weather. The company’s Electron rocket launched from Mahia Peninsula on New Zealand’s North Island with a technology demonstration satellite for DARPA, the U.S. military research and development agency.

The United Launch Alliance Atlas 5 rocket, standing 191 feet tall and and weighing 720,000 pounds, unleashes 860,000 pounds of thrust from its main engine at 9:49:51 a.m. local time today to launch the secret NROL-79 payload for the U.S. National Reconnaissance Office from Vandenberg Air Force Base, California.