US Military Launching Spy Satellite with World's Biggest Rocket

The world’s largest rocket is set to launch a classified satellite into Earth's orbit on Thursday afternoon for the National Reconnaissance Office (NRO), which is a secretive branch of the U.S. federal government that oversees spy satellites for various agencies. 

The exact details of the satellite and its mission have not been released to the public since the operation "supports national security.”  

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The official orbital destination for this mission, known NROL-37, remains a secret. However, analysts believe that it is being sent to a geostationary orbit where other reconnaissance satellites have been placed. 

The 236-foot-tall rocket, weighing over 1.6 million pounds, will travel with the NRO satellite more than 22,000 miles above the equator. The Delta IV Heavy rocket is the largest U.S. rocket currently in operation and was designed by the United Launch Alliance.

The last time the Delta-4 Heavy flew was in December of 2014, when the vehicle was used to launch an uncrewed version of NASA’s Orion spacecraft for Exploration Flight Test 1.

The NRO was originally established in 1961, just four years after the Soviet Union launched the the satellite Sputnik 1. The agency worked in secret for more than three decades before its existence was finally declassified in 1992.