Video: NROL-37 payload and Delta 4-Heavy rocket prepped for launch

The United Launch Alliance Atlas 5 rocket, standing 189 feet tall and and weighing 840,000 pounds, unleashes 1.2 million pounds of thrust from its main engine and one side-mounted booster at 7:05 p.m. EDT (2305 GMT) today to launch NASA’s OSIRIS-REx mission to Asteroid Bennu.

The last unflown variant of United Launch Alliance’s Atlas 5 launcher — fitted with a five-meter fairing and a single strap-on solid rocket booster — will carry a pair of U.S. military space surveillance satellites toward geosynchronous orbit from Cape Canaveral late this year, according to a Space Force spokesperson.

Another countdown for United Launch Alliance’s next Delta 4-Heavy rocket mission ended without a liftoff Wednesday after a computer sequencer detected a potential problem just before engine ignition.