Space Shuttle Main Engine (SSME) Test [NASA Photograph]; HQL-219

The format is approximately 8 inches by 10 inches. This is a single sheet, with imagery on the front and printing on both sides, in a plastic sleeve. On the front side is a large color photograph of the Space Shuttle Main Engine (SSME) Test. The other side has a brief discussion of the main engine during a full-mission duration static test. The image is undated but from the text on the back this image is believed to be circa 1988. During the course of the Space Shuttle program, a total of 46 RS-25 engines were used (with one extra RS-25D being built but never used). During the 135 missions, for a total of 405 individual engine-missions, Pratt & Whitney Rocketdyne reports a 99.95% reliability rate, with the only in-flight SSME failure occurring during Space Shuttle Challenger's STS-51-F mission. The RS-25, also known as the Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is used on the Space Launch System (SLS). Designed and manufactured in the United States by Rocketdyne (later Pratt & Whitney Rocketdyne and Aerojet Rocketdyne), the RS-25 burns cryogenic (very low temperature) liquid hydrogen and liquid oxygen propellants, with each engine producing 418,000 lbf thrust at liftoff. Although RS-25 heritage traces back to the 1960s, its concerted development began in the 1970s with the first flight, STS-1, on April 12, 1981. The RS-25 has undergone upgrades over its operational history to improve the engine's reliability, safety, and maintenance load. The engine produces a specific impulse (Isp) of 452 seconds in vacuum, or 366 seconds at sea level, has a mass of approximately 7,700 pounds, and is capable of throttling between 67% and 109% of its rated power level in one-percent increments. Components of the RS-25 operate at temperatures ranging from 400 to 6,000 °F. The Space Shuttle used a cluster of three RS-25 engines mounted at the stern of the orbiter, with fuel drawn from the external tank. The engines were used for propulsion throughout the spacecraft ascent, with total thrust increased by two solid rocket boosters and the orbiter's two AJ10 orbital maneuvering system engines. Following each flight, the RS-25 engines were removed from the orbiter, inspected, refurbished, and then reused on another mission. Four RS-25 engines are installed on each Space Launch System, housed in the engine section at the base of the core stage, and expended after use. Single sheet, printed on both sides Presumed First Edition, First printing. This is one of the multiple originals issued. …