Lincoln Near-Earth Asteroid Research

Number of NEOs detected by various projects.

The LIncoln Near-Earth Asteroid Research (LINEAR) project is a cooperative project between the United States Air Force, NASA, and MIT's Lincoln Laboratory for the systematic discovery and tracking of near-Earth asteroids. LINEAR was responsible for the majority of asteroid detections since 1998 until overtaken by the Catalina Sky Survey. As of December 31, 2007, LINEAR had detected 226,193 new objects of which at least 2019 were near-Earth asteroids and 236 were comets.[1] All of LINEAR's discoveries were made using robotic telescopes.

The initial field tests go back to 1972. In the early 1980s, a prototype was built, the Lincoln Laboratory ETS (Experimental Test System), New Mexico (MPC observatory code 704). The LINEAR project began operating a near-Earth object (NEO) discovery facility using a one-meter aperture Ground-based Electro-Optical Deep Space Surveillance (GEODSS) telescope in 1996. Such wide-field Air Force telescopes were designed for optical observation of Earth orbital spacecraft. The GEODSS instruments used by the LINEAR program are located at the Lincoln Laboratory's experimental test site in the White Sands Missile Range at Socorro, New Mexico. Data is then sent to the Lincoln Laboratory at Hanscom Air Force Base in Lexington, Massachusetts.

Between March and July 1997, a 1024 × 1024 Charge-coupled device (CCD) pixel detector was used in field tests and, while this CCD detector filled only about one fifth of the telescope's field of view, four near-earth objects were discovered. In October 1997, a large format CCD, of 1960 × 2560 pixels, which covered the telescope's two-square degree field of view was employed successfully to discover a total of nine new near-earth objects (NEOs). Five more NEOs were added between November 1997 through January 1998, when both the small and large format CCD detectors were employed.[2]

Beginning in October 1999, a second one-meter telescope was added to the search effort.[3] In 2002, a third telescope of 0.5 meter aperture was brought on-line to provide follow-up observations for the discoveries made by the two 1-meter search telescopes.[3] Currently, LINEAR telescopes observe each patch of sky 5 times in one evening with most of the efforts going into searching along the ecliptic plane where most NEOs would be expected. The sensitivity of their CCDs, and particularly their relatively rapid read out rates, allows LINEAR to cover large areas of sky each night. Currently, the LINEAR program is responsible for the majority of NEO discoveries.

The project's principal investigator is Grant Stokes, and co-investigators include Jenifer Evans and Eric Pearce.

In addition to discovering tens of thousands of asteroids (67,820 as of June 13, 2006), LINEAR is also credited with the discovery, or co-discovery, or rediscovery of several periodic comets, including 11P/Tempel-Swift-LINEAR, 146P/Shoemaker-LINEAR, 148P/Anderson-LINEAR, 156P/Russell-LINEAR, 158P/Kowal-LINEAR, 160P/LINEAR (LINEAR 43), 165P/LINEAR (LINEAR 10), and 176P/LINEAR (LINEAR 52, 118401 LINEAR: one of only five objects classified both as comets and asteroids).

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