Peenemuende team moved from White Sands to Huntsville

Von Braun report 'A Minimum Satellite Vehicle Based on Components Available from Developments of the Army Ordnance Corps' in response to June Pentagon meeting proposes $ 100,000 to launch satellite by Redstone.

Research and development Policy Council (DOD) unanimously recommended that the time-risk factor in the scientific satellite program be brought to the attention of the Secretary of the Defense for determination as to whether a Redstone backup program was indicated.

Von Braun briefs Secretary of Defence McElroy on Jupiter-C/Redstone for immediate US satellite launch. Promises launch in 60 days. Medaris says 90.

Secretary of Defense Neil McElroy directed the Army to proceed with the launching of the Explorer earth satellites. This order, in effect, resumed the Orbiter project that had been eliminated from the IGY satellite planning program on September 9, 1955. Von Braun was to modify two Jupiter-C missiles (modified Redstones) and attempt to place an artificial earth satellite in orbit by March 58.

Explorer I, the first U.S. earth satellite, was launched by a modified Army Ballistic Missile Agency Jupiter-C. Explorer I, developed by the Jet Propulsion Laboratory, carried the U.S.-IGY (International Geophysical Year) experiment of James A. Van Allen and resulted in the discovery of the radiation belt around the earth.

Radiation, micrometeoroid data.

Mapped project Argus radiation.

First Earth photo; radiation data.

Spacecraft engaged in research and exploration of the upper atmosphere or outer space. Returned magnetic field and solar flare data.

Ionospheric research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

12 foot dia. balloon; atmospheric density studies. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Magnetic field data. Decay date suspect Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Gamma ray data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Micrometeorite counter satellite (S-55).

Radiation and solar wind data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Useless orbit; micrometeoroid research. Partial Failure.

Magnetosphere studies. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Radiation decay data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Micrometeoroid data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Atmospheric research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Radiation data; Interplanetary Monitoring Program. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

12 foot dia. balloon; identical to Explorer 9; atmospheric density studies. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Also known as Explorer S-66.

Ionospheric research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Lower than planned orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Ionospheric and geodetic data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space.

Micrometeoroid data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

12 foot dia. balloon; atmospheric density studies. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Battery failed in 1968; ionospheric research and geodetic data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space.

Magnetic field, radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

The primary objective of GEOS-A was to provide global geodetic measurements for determining the positions of fiducial control points on the Earth to an accuracy of 10 meters in an Earth centre of mass co-ordinate system, and to determine the structure of the Earth's gravity field to 5 parts in 10 million. Instrumentation included (1) four optical beacons, (2) laser reflectors, (3) a radio range transponder, (4) Doppler beacons, and (5) a range and range rate transponder. These were designed to operate simultaneously to fulfil the objectives of locating observation points (geodetic control stations) in a three dimensional earth centre-of-mass co-ordinate system within 10 m of accuracy, of defining the structure of the earth's irregular gravitational field and refining the locations and magnitudes of the large gravity anomalies, and of comparing results of the various systems onboard the spacecraft to determine the most accurate and reliable system. In January 1967, a failure in the satellite's command system rendered several geodetic systems inoperable. Radio doppler measurements and the passive laser reflector experiment could continue indefinitely, however.

Solar radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Ionospheric research; data correlated with Alouette 2. The Explorer 31, Direct Measurement Explorer, was launched with a Canadian Alouette II on November 28, 1965, on a Thor-Agena rocket from Vandenberg Air Force Base, California. The double-launch project, known as ISIS-X was the first in a new co-operative NASA-Canadian Defense Research Board program for International Satellites for Ionospheric Studies. Explorer 31 was in orbit with an apogee just over a kilometre more than Alouette's and with a perigee of just more than a kilometre lower. The orbits were some 3000 km at apogee and 500 km at perigee. Eight ionospheric measurement experiments sampled the environment both forward and after the satellite's path.

Atmospheric Explorer; aeronomy experiments. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Intended to enter lunar orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Radiation, magnetic field data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Earth magnetic tail measurements. Lunar Orbit (Selenocentric). The Westinghouse Aerospace Division, under contract to National Aeronautics and Space Administration's Goddard Space Flight Center, engaged in the system design, integration, assembly and launch support for Anchored Interplanetary Monitoring Platform Satellite, officially designated Explorer 35 by the National Aeronautics and Space Administration. It was launched on July 19, 1967, with the primary objectives of investigation of interplanetary plasma and the interplanetary magnetic field out to and at the lunar distance, in either a captured lunar orbit or a geocentric orbit of the earth. In the geocentric orbit, the apogee was near or beyond the lunar distance. In a lunar orbit, additional objectives included obtaining data on dust distribution, lunar gravitational field, ionosphere, magnetic field, and radiation environment around the moon. AIMP-E also studied spatial and temporal relationships of geophysical and interplanetary phenomena simultaneously being studied by several other National Aeronautics and Space Administration satellites. The investigation in the vicinity of the moon provided for measurements of the characteristics of the interplanetary dust distribution, solar and galactic cosmic rays, as well as a study of the magnetohydrodynamic wake of the earth in the interplanetary medium at the lunar distances.

The geodetic instrumentation systems included (1) four optical beacons, (2) two C-band radar transponders, (3) a passive radar reflector, (4) a sequential collation of range radio range transponder, (5) a Goddard range and range rate transponder, (6) laser reflectors, and (7) Doppler beacons. Non-geodetic systems included a laser detector and a Minitrack interferometer beacon. The objectives of the spacecraft were to optimise optical station visibility periods and to provide complementary data for inclination-dependent terms established by the Explorer 29 (GEOS 1) gravimetric studies. The spacecraft was placed into a retrograde orbit to accomplish these objectives. Operational problems occurred in the main power system, optical beacon flash system, and the spacecraft clock, and adjustments in scheduling resulted in nominal operations.

Solar Explorer B; radiation data; off-nominal orbit.

Radio Astronomy Explorer; Earth, solar, cosmic radio emission data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Injun Explorer; radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Air Density Explorer; atmospheric density and temperature data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Cislunar radiation data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Earth magnetosphere research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Solar radition data. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Studies magnetosphere, energetic particles. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Micrometeoroid tests. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Investigated cislunar radiation, Earth's magnetosphere, interplantary magnetic field. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).

Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Radio Astronomy Explorer; measured galactic, stellar radio noise. Lunar Orbit (Selenocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Solar flare and radiation monitor. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Atmospheric Explorer; upper atmospheric research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Solar wind experiments. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Atmospheric Explorer; atmospheric research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Atmospheric Explorer. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

Dual Air Density; air density experiments.