US Spy Satellite Launches Atop World's Most Powerful Rocket

Delta IV Heavy Rocket Launches NROL-37 Spy Satellite
A United Launch Alliance Delta IV Heavy rocket launches into space carrying the classified NROL-37 satellite from Cape Canaveral Air Force Base in Florida on June 11, 2016. The launch is a mission for the U.S. National Reconnaissance Office. (Image credit: United Launch Alliance)

A new U.S. spy satellite roared into orbit Saturday (June 11) atop the most powerful rocket currently in operation.

The National Reconnaissance Office's (NRO) NROL-37 satellite launched Saturday at 1:51 p.m. EDT (1751 GMT) from Cape Canaveral Air Force Station in Florida, riding a United Launch Alliance (ULA) Delta IV Heavy rocket to space. (You can see a replay of the spectacular rocket launch here.)

The NRO is responsible for designing, building and operating the United States' fleet of spy satellites. As is the case with most NRO payloads, NROL-37's activities are classified; a brief description on ULA's website states that the mission is "in support of national defense." [See more launch photos for NROL-37 and its big rocket]

The Delta IV Heavy rocket, which stands 232 feet (71 meters) tall, consists of three "common booster cores" strapped together. The middle booster is topped with a second stage and the payload (in this case, NROL-37).

At launch, the Delta IV Heavy generates about 2.1 million lbs. (950,000 kilograms) of thrust, making it the most powerful rocket in use today. That's a lot, but far shy of the all-time record; NASA's Saturn V rocket, which blasted the Apollo astronauts toward the moon in the late 1960s and early 1970s, produced 7.5 million lbs. (3.4 million kg) of thrust at liftoff.

Another view of the United Launch Alliance Delta IV rocket launching the classified NROL-37 spy satellite into orbit from Space Complex 37 at Cape Canaveral Air Force Station, Florida on June 11, 2016. (Image credit: United Launch Alliance)

Two superpowerful American rockets are scheduled to come online in the next few years. SpaceX's Falcon Heavy, whose maiden flight is slated for late this year, will generate about 5 million lbs. (2.3 million kg) of thrust at liftoff, company representatives have said. And NASA's Space Launch System (SLS) megarocket will produce 10 to 20 percent more thrust than the Saturn V when it starts flying in 2018.

The initial SLS configuration will boast 8.4 million lbs. (3.8 million kg) of launch thrust, while a brawnier "evolved" version will produce 9.2 million lbs. (4.2 million kg), NASA officials have said. The space agency is developing SLS to launch the Orion crew capsule toward Mars, asteroids and other destinations in deep space.

Today's NROL-37 launch had been scheduled for Thursday (June 9), but bad weather pushed the liftoff back by two days.

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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.