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. 
•    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." 
•    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.