Figure 3.1

Survey completeness after 10 years versus diameter of NEOs for various system-limiting magnitudes. All-sky coverage (approximately 15,000 degree2) is assumed each month. The photographic Schmidt telescope on Palomar Mountain (~0.5-m aperture) is capable of all-sky coverage to a limiting magnitude of 17. A single 0.5-m CCD system (e.g., LONEOS) should be able to achieve all-sky coverage to a limiting magnitude of 19. A system of one or two 1-m telescopes should be able to survey to about limiting magnitude 20. To reach limiting magnitude 21 will probably take a system of several 2-m telescopes.

covering the entire accessible sky (about 15,000 degree2) each month to detect all observable asteroids to apparent magnitude 19.5. It is expected that about 80% of the Earth-crossing objects of 1-km diameter or greater could be detected by LONEOS in 10 years of full operation (see Figure 3.1). It must be noted, however, that LONEOS by itself could not carry out sufficient astrometric follow-up observations to obtain reliable orbits on the NEOs detected. To do this would require an approximate doubling of telescopic resources (either a second dedicated telescope of comparable aperture or the use of multiple smaller telescopes).

If the 1.8-m Spacewatch telescope under construction were to be instrumented with appropriate large-format CCDs, it could be operated in a program similar to that of LONEOS. Such a program would lead to detection of about 95% of Earth crossers of 1-km size in 10 years (see curve for limiting magnitude 22 in Figure 3.1). The LONEOS and Spacewatch systems used in a coordinated program of detection and orbit determination could yield the orbital elements for about 1000 new Earth-crossing asteroids larger than 1-km diameter, as well as thousands of smaller NEOs, in 10 to 15 years. Continued support of these projects would be necessary to achieve this goal. Participation of the NEAT system and international observers would ensure that high-precision orbits were obtained for most of the bright NEOs discovered. COMPLEX supports the coordination of ongoing NEO search programs.

There is a possibility that the U.S. Air Force, as an expansion of the NEAT project, will undertake a more intensive survey of NEOs in collaboration with NASA, using the U.S. Air Force's GEODSS satellite-tracking network upgraded with large-format CCD cameras. Such a program would have a capability similar to that of the



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