RS-88

StatusActiveLiquid-fuel enginePropellantLOX / Ethanol
MMH / NTO (LAE variant)CycleGas-generatorPerformanceThrust, sea-level220 kN (49,000 lb_f) (ethanol)
176.6 kN (39,700 lb_f) (hypergolic)Used inCST-100 Starliner

The RS-88 (Rocket System-88) is a liquid-fueled rocket engine designed and built in the United States by Rocketdyne (later Pratt & Whitney Rocketdyne and then Aerojet Rocketdyne). Originally developed for NASA's Bantam System Technology program in 1997, the RS-88 burned ethanol fuel with liquid oxygen (LOX) as the oxidizer. It offered 220 kN (49,000 lb_f) of thrust at sea level.

A hypergolic derivative of the RS-88, fueled by monomethylhydrazine and nitrogen tetroxide, was chosen as the launch escape motor for the Boeing Starliner capsule.

The RS-88 stemmed from NASA's Bantam System Technology Project, part of the Low-Cost Technologies effort of the larger Advanced Space Transportation Program.^[1] This project aimed to research and demonstrate technologies for a new, affordable launch system. While the program envisioned a technology demonstration flight in late 1999, it ultimately focused on engine development.^[2]

NASA tested the RS-88 in a series of 14 hot-fire tests, resulting in 55 seconds of successful engine operation in November and December 2003.

In 2003, Lockheed Martin selected the RS-88 for their pad abort demonstration vehicle. NASA successfully tested the engine in a series of hot-fire tests, demonstrating its reliability.

A hypergolic derivative of the RS-88, fueled by monomethylhydrazine (MMH) and nitrogen tetroxide, was chosen as the launch escape motor for the Boeing Starliner capsule.^[3] This variant, called the Launch Abort Engine (LAE), provides 176.6 kN (39,700 lb_f) of thrust.^[4] Four LAE engines are used in Starliner's abort system to propel the capsule away from the launch vehicle in case of an emergency.^[5]

• NASA Advanced Space Transportation Program
• Merlin (rocket engine)

• Marshall SFC Star June 11, 1997.
• RS-88 PAD Testing at NASA MSFC May 2005, AIAA