Lincoln Near-Earth Asteroid Research
The Lincoln Near-Earth Asteroid Research (LINEAR) project is a collaboration of the United States Air Force, NASA, and the Massachusetts Institute of Technology's Lincoln Laboratory for the systematic discovery and tracking of near-Earth asteroids. LINEAR was responsible for the majority of asteroid detections from 1998 until it was overtaken by the Catalina Sky Survey in 2005. As of 15 September 2011[ref], LINEAR had detected 231,082 new objects, of which at least 2,423 were near-Earth asteroids and 279 were comets. The instruments used by the LINEAR program are located at the Lincoln Laboratory's site on the White Sands Missile Range (WSMR) near Socorro, New Mexico.
In the late 1970s, a prototype called the Lincoln Laboratory Experimental Test System (ETS) (MPC code 704) was built at WSMR. The project used low-light video cameras. In 1994 a new proposal was made for automated detection of asteroids, this time using newer digital detector technology. The LINEAR project began operating a near-Earth object (NEO) discovery facility in 1996 using a 1.0 m (39 in) aperture telescope designed for the Air Force Space Command's Ground-based Electro-Optical Deep Space Surveillance (GEODSS). The wide-field Air Force telescopes were designed for optical observation of Earth-orbiting spacecraft. Initial field tests used a 1024 × 1024 pixel charge-coupled device (CCD) detector. While this CCD detector filled only about one fifth of the telescope's field of view, four near-earth objects were discovered. A 1960 × 2560 pixel CCD which covered the telescope's two-square degree field of view was then installed, and both detectors were used in later tests.
The first LINEAR telescope became fully operational in March 1998. Beginning in October 1999, a second 1.0 m telescope was added to the search effort. In 2002, a 0.5 m (20 in) telescope equipped with the original CCD was brought on-line to provide follow-up observations for the discoveries made by the two search telescopes. This allowed about 20% more of the sky to be searched each night. Data recorded by the telescopes is sent to a Lincoln Laboratory facility at Hanscom Air Force Base in Lexington, Massachusetts for processing. Detections are then forwarded to the Minor Planet Center.
In addition to discovering hundreds of thousands of asteroids, LINEAR is also credited with the discovery, or co-discovery, or rediscovery of several periodic comets, including 11P/Tempel-Swift-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). Other objects discovered include (137108) 1999 AN10, 2002 TD66, and 2004 FH.
See also 
- "NEO Discovery Statistics". NASA Near Earth Object Program. Retrieved 2012-01-19.
- "MIT Lincoln Laboratory: LINEAR". MIT Lincoln Laboratory. Retrieved 2012-01-19.
- Beatty, D. E.; Sorvari, J. M.; Taff, L. G. (1980). "Artificial satellites, minor planets, and the ETS". Unknown 81: 12143. Bibcode:1980STIN...8112143B.
- Taff, L. G. (1981). "A new asteroid observation and search technique". Astronomical Society of the Pacific 93: 658. Bibcode:1981PASP...93..658T. doi:10.1086/130905.
- Tennyson, Peter D. (1994). "Applying electro-optical space surveillance technology to the detection of near-Earth asteroids". Proceedings of SPIE 2198. p. 1286. doi:10.1117/12.176813.
- "Lincoln Near-Earth Asteroid Research (LINEAR)". NASA Near Earth Object Program. Retrieved 2012-01-19.
- Stokes, G. H.; Viggh, H. E. M.; Shelly, F. L.; Blythe, M. S.; Stuart, J. S. (1998). "Results from the Lincoln Near Earth Asteroid Research (LINEAR) Project". American Astronomical Society 30: 1042. Bibcode:1998DPS....30.1607S.
- Elowitz, R. M.; Stokes, G. H.; Bezpalko, M.; Blythe, M. S.; Evans, J. B.; Pearce, E. C.; Sayer, R. W.; Shelly, F. C. et al. (1999). "A Progress Report on the Lincoln Near Earth Asteroid Research Project". American Astronomical Society 195: 1531. Bibcode:1999AAS...19510801E.
- Stokes, G. H.; Evans, J. B.; Shelly, F. C. (2002). "LINEAR Search and Operations Experience". American Astronomical Society 201: 1315. Bibcode:2002AAS...20113003S.
- MIT Lincoln Laboratory: LINEAR
- NEO discovery statistics from JPL. Shows the number of asteroids of various types (potentially hazardous, size >1 km, etc.) that different programs have discovered, by year.
- Sky Database for Objects in Time-Domain provides corrected LINEAR data.