English: In this photo, an RS-88 development rocket engine is being test fired at NASA's Marshall Space Flight Center in Huntsville, Alabama, in support of the Pad Abort Demonstration (PAD) test flights for NASA's Orbital Space Plane (OSP). The tests could be instrumental in developing the first crew launch escape system in almost 30 years. Paving the way for a series of integrated PAD test flights, the engine tests support development of a system that could pull a crew safely away from danger during liftoff. A series of 16 hot fire tests of a 50,000-pound thrust RS-88 rocket engine were conducted, resulting in a total of 55 seconds of successful engine operation. The engine is being developed by the Rocketdyne Propulsion and Power unit of the Boeing Company. Integrated launch abort demonstration tests in 2005 will use four RS-88 engines to separate a test vehicle from a test platform, simulating pulling a crewed vehicle away from an aborted launch. Four 156-foot parachutes will deploy and carry the vehicle to landing. Lockheed Martin is building the vehicles for the PAD tests. Seven integrated tests are planned for 2005 and 2006.