Lockheed Martin and Boeing joint venture United Launch Alliance received a $373 million contract from the US Air Force to deliver launch vehicle platforms for two National Reconnaissance Office (NRO) rockets. According to the Department of Defense, this is part of the NRO’s 2013 $11 billion sole-source block buy for ULA’s services. Under the contract, ULA is to provide one Delta IV Heavy rocket and one Atlas V rocket with a four-meter fairing and two solid strap-on motors.
Available in five variants, the Delta IV rocket is touted as an efficient, streamlined, and simply designed launch vehicle ideal for taking payloads into orbit. High-priority operators of the Delta IV launch vehicle include NASA, NRO, and the USAF. Each of the five Delta IV configurations -the Delta IV Medium (Delta IV M), three variants of the Delta IV Medium-Plus (Delta IV M+), and the Delta IV Heavy (Delta IV H) -sport a cryogenic upper stage, a common booster core (CBC), and either a 4-meter or 5-meter diameter payload fairing (PLF).
Backed by a Pratt & Whitney Rocketdyne RS-68A engine, the Delta IV is propelled by the industry’s largest hydrogen-burning engine. The throttable RS-68A engine consists of 80% fewer components than the main engine of the Space Shuttle. The 204-inch-long, 14,876-pound engine boasts a nominal thrust of 702,000 pounds and a specific impulse of 275.2 seconds.
The Delta IV and the Atlas rockets both depend on the RL10 engine for their second stages. Also manufactured by Pratt & Whitney Rocketdyne, the RL10 propulsion system touts a track record of 385 successful flights and 700 firings in orbit. Burning liquid hydrogen, the 163.5-inch-long, 84.5-inch-wide RL10 engine exhibits a nominal thrust of 24,750 pounds, a specific impulse of 465.5 seconds, and weighs 664 pounds.
Work on the contract is to be performed at ULA’s Alabama and Colorado facilities as well as at Vandenberg Air Force Base in California. The work is estimated to be finished by January 30, 2019.