Atlas V Rocket to Launch US Spy Satellite Overnight Tonight: Watch Live

NROL-42 payload fairing
The classified NROL-42 spy satellite is hoisted to meet its United Launch Alliance Atlas V rocket ahead of a planned late-night launch on Sept. 23, 2017 from Vandenberg Air Force Base in California for the U.S. National Reconnaissance Office. (Image credit: United Launch Alliance)

A U.S. spy satellite will launch on a clandestine mission early Sunday (Sept. 24), and you can follow the spaceflight action live online.

The NROL-42 satellite is scheduled to lift off from California's Vandenberg Air Force Base at 1:30 a.m. EDT (0530 GMT; 10:30 p.m. Saturday local California time) atop a United Launch Alliance (ULA) Atlas V rocket. You can watch the launch here on beginning at 1:10 a.m. EDT (0510 GMT; 10:10 p.m. PDT), courtesy of ULA. 

You can also watch the liftoff directly via ULA's website here

The launch was originally scheduled to take place early Friday (Sept. 22), but ULA pushed it back to replace a faulty battery on the Atlas V.

NROL-42 will be operated by the U.S. National Reconnaissance Office (NRO), which builds and manages the nation's fleet of spy satellites. NRO missions tend to be classified, and NROL-42 is no exception; U.S. officials have not revealed what the spacecraft will be doing or what its orbit will be. [The Most Dangerous Space Weapons Ever]

The National Reconnaissance Office's NROL-42 satellite is scheduled to launch atop a United Launch Alliance Atlas V rocket early on Sept. 24, 2017. (Image credit: ULA)

NROL-42 will be the 25th satellite that ULA, a joint venture of aerospace giants Boeing and Lockheed Martin, has launched for the NRO. The 24 previous flights — which were performed by Atlas V, Delta IV and Delta II rockets — have all been successful.

The upcoming liftoff will be the 73rd for the two-stage Atlas V, which debuted in 2002 and has lofted such high-profile payloads as NASA's Mars rover Curiosity and New Horizons spacecraft. All Atlas V launches to date have been successful.

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.