Explorer S-46 was a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

satellite with a mass of . It was the last of the original series of Explorer satellites built, designed, and operated by the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

and

Army Ballistic Missile Agency The Army Ballistic Missile Agency (ABMA) was formed to develop the U.S. Army's first large ballistic missile. The agency was established at Redstone Arsenal on 1 February 1956, and commanded by Major General John B. Medaris with Wernher von ...

(ABMA).

Mission

Its mission was to analyze

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...

and

proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

radiation energies in a

highly elliptical orbit A highly elliptical orbit (HEO) is an elliptic orbit with high eccentricity, usually referring to one around Earth. Examples of inclined HEO orbits include Molniya orbits, named after the Molniya Soviet communication satellites which used them ...

Spacecraft

Explorer S-46 was a joint ABMA / NASA-JPL mission. The payload detector experiments were developed by the

State University of Iowa The University of Iowa (UI, U of I, UIowa, or simply Iowa) is a public research university in Iowa City, Iowa, United States. Founded in 1847, it is the oldest and largest university in the state. The University of Iowa is organized into 12 coll ...

. The detector assembly comprised five instruments: a

Cadmium sulfide Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare m ...

(CdS) broom low-energy proton detector, a

(CdS) low-energy particle detector; an electron spectrometer; a Geiger-Müller high-energy particle counter; and a Geiger-Müller medium energy particle counter. These were housed in the front of the Sergeant rocket engine that comprised the fourth (upper-stage) of the Juno II launch vehicle.

Payload experiments

* Cadmium sulfide (CdS) Proton Detector * Cadmium sulfide (CdS) Particle Detector * Electron Spectrometer * High Energy Geiger–Müller Tube * Medium Energy Geiger-Müller Tube

Juno II

The four-stage Juno II launch vehicle used a Jupiter missile engine as the first stage. The second stage was assembled as a circumferential "tub" of 11 scaled-down Sergeant rocket engines (solid propellant), the third stage was assembled as three scaled-down Sergeant rocket engines nested in the center of the "tub", and a single modified Sergeant rocket engine and casing comprising the fourth stage was mounted on top of this.

Launch

Explorer S-46 was launched using a Juno II

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pad, launch pads, supported by a missile launch contro ...

on 23 March 1960, at 13:35:11

GMT Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a cons ...

, from LC-26B. Telemetry was lost shortly after the first stage burnout and one second stage motor failed to ignite, resulting in imbalanced thrust and inability to reach orbital velocity. The spacecraft did not achieve orbit.

References