The Delta II is the modern version of the Delta rockets that were first launched in the 1960's. Steady technological advances and increases in power by using more powerful boosters produced a rocket of unequaled reliability. It has launched dozens of NASA missions, including one of the agency's great observatories, and three Mars rovers. It is used for medium-sized payloads.
The Delta II is a three-stage, liquid-fueled vehicle. A single RS-27 engine fed with liquid oxygen (LOX) and rocket grade kerosene powers the first stage, which can be supplemented by up to nine solid rocket boosters.
A hypergolic (combustion occurs when the oxidizer and fuel mix, without the aid of a heat source) Aerojet AJ10-118K engine powers the second stage, which also houses the avionics. Finally, the vehicle can use an optional solid motor kick stage, by Alliant Techsystems (ATK) Thiokol, for missions to points beyond LEO. Three different payload fairings are available depending on payload dimensions.
ULA designed, built, and operates the Delta II launch vehicle, an intermediate class vehicle. There are many variants of the Delta II, depending on booster, stage, and fairing configuration. Along with the Delta IV and Atlas V, ULA brokers Delta II launch services to the U.S. Government. Boeing Launch Services (BLS) markets the Delta II to commercial clients.
United Launch Alliance offers multiple configurations of the Delta II with the 10-foot diameter fairing. The number of solid rocket boosters varies between 3 and 9 dependent on the weight of the payload. The Delta II can carry a payload up to 11,150 lbs (5,058 kg) to Low Earth Orbit.
A Delta II can launch a satellite to Low Earth Orbit (LEO) that is the equivalent weight of a Mercedes S500 sedan, approximately 1,905 kilograms (4,200 pounds).