Encyclopedia Astronautica
Early Spring


American military anti-satellite system. Studied from 1960, officially cancelled, but possibly developed further as a black program. Early Spring was a conventional ASAT launched by Polaris missiles from US Navy ballistic missile submarines.

The principle was that the submarine could take a position under the path of the satellite. As it passed overhead, a Polaris missile would be launched with a peak altitude close to that of the target. The ASAT used a restartable upper stage to 'hover' for up to 90 seconds awaiting the satellite. An optical homing system would first locate, then track the target satellite. A datalink was provided to the submarine for control. Once committed, the ASAT would put itself on a collision course with the target. A proximity fuse would detonate a warhead with thousands of steel pellets. To assure a kill, more than one ASAT could be launched simultaneously by the submarine.

Early Spring was first presented to Congress in March 1961. By 1964 several alternate configurations were evaluated, and by the late 1960's the optical tracker was showing good results in tests. The project was officially cancelled in the late 1960's. However the same concept can be found in the Navy's manned Space Cruiser concepts of the early 1970's and 1980's. And in 1978 the Joint Chiefs of Staff directed that work began on a "low-risk ASAT system using off-the-shelf technology..... employing pellets as its kill mechanism...." which may indicate the original system went operational and black.

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Associated Countries
See also
Associated Launch Vehicles
  • Polaris American submarine-launched ballistic missile. Probably the most technically innovative program in history, Polaris integrated solid-propellant, inertially-guided intermediate range ballistic missiles with nuclear submarines that could remain submerged for months at a time. All of these were new technologies, but the first ship was underway only three years after go-ahead. More...
  • Polaris A3 American missile. Two stage vehicle consisting of 1 x A3P + 1 x X-260 More...

Associated Manufacturers and Agencies
  • NRL American manufacturer of rockets and spacecraft. Naval Research Laboratory, Washington, DC, USA. More...
  • Lockheed American manufacturer of rockets, spacecraft, and rocket engines. Lockheed Martin, Sunnyvale, CA, USA. More...

Bibliography
  • Federation of American Scientists Web Site, Web Address when accessed: here.

Early Spring Chronology


1961 March - .
  • Early Spring first presented to Congress. - . Nation: USA. Spacecraft: Early Spring. Early Spring was a conventional ASAT launched by Polaris missiles from US Navy ballistic missile submarines. As an enemy satellite passed overhead, a Polaris missile would be launched. The ASAT used a restartable upper stage to 'hover' in front of the oncoming satellite. An optical homing system would first locate, track the target satellite, and then ASAT would put itself on a collision course with the target. A proximity fuse would detonate a warhead with thousands of steel pellets.

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