The Scout family of rockets were American launch vehicles designed to place small satellites into orbit around the Earth. The Scout multistage rocket was the first (and for a long time, the only) orbital launch vehicle to be entirely composed of solid fuel stages.
The original Scout (an acronym for Solid Controlled Orbital Utility Test system) was designed in 1957 at the NACA Langley center. Scout launch vehicles were used from 1961 until 1994. To enhance reliability the development team opted to use "off the shelf" hardware, originally produced for military programs. According to the NASA fact sheet:
"... the first stage motor was a combination of the Jupiter Senior and the Navy Polaris; the second stage came from the Army MGM-29 Sergeant; and the third and fourth stage motors were designed by Langley engineers who adapted a version of the Navy Vanguard."
The first successful orbital launch of a Scout, on February 16, 1961, delivered Explorer 9, a 7-kg satellite used for atmospheric density studies, into orbit. The final launch of a Scout, using a Scout G-1, was on May 8, 1994 local time (May 9, 1994 02:47 GMT) from Vandenberg Air Force Base. The payload was the Miniature Sensor Technology Integration Series 2 (MSTI-2) military spacecraft with a mass of 163 kg. Per NASA, MSTI-2 successfully acquired and tracked a LGM-30 Minuteman.
The standard Scout launch vehicle was a solid propellant, four-stage booster system, approximately 75 feet (23 m) in length with a launch weight of 47,398 pounds (21,500 kilograms).
Stage 1: Algol