Discoverer II (initially known as STARLITE) was a joint

DARPA The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Adv ...

, Air Force, and

National Reconnaissance Office The National Reconnaissance Office (NRO) is a member of the United States Intelligence Community and an agency of the United States Department of Defense which designs, builds, launches, and operates the reconnaissance satellites of the U.S. f ...

project to build and launch a

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

(LEO) constellation for space-based radar. The project began in 1998 but was canceled by Congress in 2000. The Discoverer II concept dates back to June 1996, when the

Director of Central Intelligence The director of central intelligence (DCI) was the head of the American Central Intelligence Agency from 1946 to 2005, acting as the principal intelligence advisor to the president of the United States and the United States National Security C ...

's Small Satellite Review Panel concluded that: "...now is an appropriate time to make a qualitative change in the systems architecture of the nation's reconnaissance assets... We see the opportunity to move towards an operational capability for the country, at least for imagery systems, that consists of an array of smaller, cheaper spacecraft in larger numbers which is at least as useful as those currently planned and to transport them to space with substantially smaller and less costly launch vehicles." The

Defense Science Board The Defense Science Board (DSB) is a committee of civilian experts appointed to advise the U.S. Department of Defense on scientific and technical matters. It was established in 1956 on the recommendation of the second Hoover Commission. Charter ...

(DSB) was then asked to establish a Task Force on Satellite Reconnaissance (the so-called "Hermann Panel") to review all major aspects of such small satellite systems for defence. In its January 1998 report, the Task Force recommended that a modified STARLITE program be initiated, as a "Military Space Radar Surveillance Program," in an effort to achieve broad-area, all-weather, near-continuous radar access that could be integrated with military operations. In February 1998 DARPA, the Air Force and the NRO established a joint program to undertake a "Space-based Radar Risk Reduction and Demonstration Program". The Discoverer II constellation was envisioned to be 24 satellites, each configured with

Synthetic Aperture Radar Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide fine ...

(SAR) and

Ground Moving Target Indication Moving target indication (MTI) is a mode of operation of a radar to discriminate a target against the clutter. It describes a variety of techniques used for finding moving objects, like an aircraft, and filter out unmoving ones, like hills or trees ...

(GMTI) radar systems. Each satellite was envisioned to cost approximately $100 million. The constellation would allow for a very rapid revisit rate (about 15 minutes) to most areas of the earth for near-continuous surveillance of terrestrial and maritime vehicles, and could produce

Interferometric SAR Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing. This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface defor ...

images for high-resolution terrain mapping. When needed, constellation tasking could be directed by a deployed Joint Task Force tactical commander. On February 22, 1999, three contractor teams were selected, led by

Lockheed Martin The Lockheed Martin Corporation is an American aerospace, arms, defense, information security, and technology corporation with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It ...

Astronautics,

Spectrum Astro Spectrum Astro was a privately held American corporation that designed, manufactured, and sold satellites. Spectrum Astro's, at the time, unique satellite production method was to design and manufacture space satellites, in their entirety, at a ...

, and TRW Defense Systems Division. After a study phase, the project planned to launch two experimental satellites for demonstration and risk reduction. The project apparently suffered difficulties, and was canceled by Congress in 2000.

References

Report by the DCI's Small Satellite Review Panel
Permanent Select Committee on Intelligence, United States House of Representatives, June 27, 1996. * "Discoverer II Program summary", D. Whelan, Radar Conference, February 2000. * "Precision Radar Surveillance and Mapping with Discoverer II", J. Koss, S. Pohleg, M. Trichel, W. Jeffrey, AIAA Space Technology Conference and Exposition, September 28–30, 1999.
High-Resolution Interferometric Synthetic Aperture Radar for Discoverer II"
Michael W. Roth, Johns Hopkins APL Technical Digest, vol. 20, no. 3, pages 297–304, 1999.
"NRO chief presses for system similar to cancelled Discoverer II"
Aerospace Daily, September 7, 2000.

Global Security

Global Security
"Radar love: the tortured history of American space radar programs"
Dwayne A. Day, The Space Review, January 22, 2007. {{DEFAULTSORT:Discoverer II Lockheed Martin satellites and probes National Reconnaissance Office satellites