A Delta 4-Heavy rocket carrying an NROL-15 spy satellite lifts off from Cape Canaveral on Friday, June 29, 2012.
The United States has launched a spy satellite into orbit on a clandestine mission for the US military.
The NROL-15 reconnaissance satellite was launched from Cape Canaveral in Florida on Friday at 9:15 a.m. EDT (1315 GMT) atop the world's most powerful rocket, the Delta 4-Heavy.
According to the manufacturers, the Delta 4-Heavy booster is equipped with new RS-68A first stage engines, the most powerful liquid hydrogen rocket engines ever manufactured in history.
The Delta 4-Heavy carried the satellite for the National Reconnaissance Office (NRO), which is not revealing any information on the satellite's purpose.
Friday's launch was the NRO’s second spy satellite launch in nine days. An Atlas 5 rocket carrying another secret satellite, the NROL-38, was launched on June 20 at 8:28 a.m. EDT (1228 GMT) from Cape Canaveral.