Main Engines

Pathfinder’s three main engines are real. The two lower engines powered the first flight of Columbia in 1981, and the engine at the top was used in ground test firings. At launch, the three Space Shuttle Main Engines, fed liquid hydrogen and oxygen from the External Tank, are ignited several seconds before liftoff. They operate for approximately 8.5 minutes of flight, drawing about 47,000 gallons of liquid hydrogen and 17,000 gallons of liquid oxygen each minute. Shortly before the shuttle achieves orbit, the main engines shut down and maneuvering rockets fire to position the shuttle into its final orbit. Reusable, each engine is designed for 7.5 hours of operation or to endure up to 55 starts. Each engine is 14 feet long, 7.5 feet in diameter, weighs approximately 7000 pounds, produces 393,800 pounds of thrust, and uses a mix ratio of 6 parts oxygen to 1 part hydrogen. The prime contractor was Rockwell International Rocketdyne Division.

Huntsville, Alabama · United States