http://www.pratt-whitney.com/prod_space_rl10.asp
pratt-whitney RL10 rocket engine

As the most reliable, safe and high performing upper stage engine in the world, the remarkable RL10 has accumulated one of the most impressive lists of accomplishments in the history of space propulsion.

Created in 1959 after Pratt & Whitney harnessed high-energy liquid hydrogen as fuel for aerospace propulsion, the RL10 has helped place numerous military, government and commercial satellites into orbit and powered space probe missions to nearly every planet in our solar system. Some of its notable interplanetary missions include the Surveyor Lunar Lander, Viking Mars Lander and the Voyager Outer Planets Fly-By, while its heritage includes supporting MILSTAR, EUTELSAT, TDRS ECHOSTAR, INTELSAT, GALAXY, DSCSIII, and JCSAT satellites.

Today, the RL10 continues its legacy as the industry workhorse as it powers the upper stage for vehicles in the Lockheed Martin Atlas and Titan rocket families. In August 2002, the engine set another milestone when it successfully propelled the payload for the inaugural Lockheed Martin Atlas V that helped set the foundation for the U.S. Air Force’s Evolved Expendable Launch Vehicle (EELV) program.

Several RL10 models are used to support various launch vehicles, depending on the payload requirements and configuration for the mission. Current engine models and their supported vehicles are as follows: RL10A-4-2 (Atlas V), RL10A-4 and RL10A-4-1 (Atlas II, IIA, IIAS, III and IIIB) and RL10A-3-3A (Titan IVB).

Engine Characteristics

Thrust: 16,500 - 22,300 lb
Weight: 310 - 370 lb
Fuel/oxidizer: Liquid hydrogen/liquid oxygen
Mixture ratio: 5.1 - 5.5:1
Specific impulse: 444.4 sec - 451.0 sec

News

November 24, 2003

Renowned Rocket Engine Celebrates 40 Years of Flight »

September 3, 2003

RL10 Model To Be Retired After Completing Upcoming Titan Flight»