The United Launch Alliance Delta IV Heavy, touted as the world's most powerful rocket, blasted off from Cape Canaveral Air Force Station in Florida Saturday, June 11, afternoon carrying a United States spy satellite.
The launch was supposed to take place on Thursday, June 9, but it was delayed for several days because of rainy weather conditions.
The 232 feet tall rocket features a center common booster core and two strap-on common booster cores individually powered by RS-68A liquid hydrogen/liquid oxygen engine generating 702,000 pounds of thrust.
Delta IV Heavy lifted off shortly before 2 p.m. EDT carrying the NROL-37 satellite of the National Reconnaissance Office (NRO) to orbit.
The NRO, which designs, builds and operates the nation's fleet of spy satellites, is one of the 17 U.S. intelligence agencies. Just as with most NRO payloads, NRO withheld detailed information about the NROL-37 satellite albeit the agency said on its website that the mission is in support of national defense.
Based on the use of Delta IV Heavy, however, there are speculations that the satellite could be one of the organization's Advanced Orion satellites that measure radio signals.
The rocket last flew in December 2014 when it carried NASA's Orion spacecraft for a two-orbit test flight around Earth. Since 2004, Delta IV Heavy has only flown nine times.
"We are so honored to deliver the NROL-37 payload to orbit for the National Reconnaissance Office during today's incredible launch," said ULA vice president of Custom Services Laura Maginnis. "This was the ninth time ULA launched the Delta IV Heavy, the most powerful launch vehicle in existence today."
Financial expense is one reason why the rocket flies so infrequently as each flight costs about $400 million.
United Launch Alliance, a joint venture of Lockheed Martin and Boeing, also has the Atlas V rocket that flies more frequently. The cost for each of these flights is about $200 million after factoring in the $800 million "capability contract" the company gets from the military for launch readiness.
In comparison, Elon Musk's SpaceX charges a mere $60 million per launch for its Falcon 9 rocket.
Cost with ULA's launches, however, is backed by reliability. The 107 launches it had with its Delta IV and Atlas V rockets were all successful. SpaceX, on the other hand, has already experienced mishap.
In June 2015, the company's Falcon 9 rocket, which was carrying a Dragon cargo vehicle bound for the International Space Station exploded. The incident marked the company's first rocket failure.
