NASA's Near-Earth Object Program
Yeomans, D.K.1; Johnson, L.N.2
1Jet Propulsion Laboratory; 2NASA Headquarters
The vast majority of NEO discoveries have been made by wide field telescopic surveys funded by NASA. This Near-Earth Object Observations Program is under the direction of Lindley Johnson of the Science Mission Directorate at NASA Headquarters. The selection of competitive peer-reviewed proposals forms the basis for NASA's funding of NEO search surveys, follow-up observation programs and efforts to provide the physical characteristics of NEOs. Currently the NEO survey teams, supported by NASA, include the Catalina Sky Survey (CSS) and Spacewatch programs near Tucson AZ, the MIT Lincoln Laboratory LINEAR program and the PanSTARRS program operated by the University of Hawaii. For several years, NASA's NEO Observations Program has also partially supported the operations budget of the Minor Planet Center in Cambridge MA, and has recently greatly increased that funding allowing them to continue receiving, processing, distributing and archiving NEO astrometric data as well as upgrading their operational capabilities to meet an expected increase of observational data.
In addition to supporting the above mentioned NEO search facilities, NASA also supports several observatories that provide the follow-up observations that are required so the orbits of newly discovered objects become secure. These critical follow-up observatories, in addition to the work done by the Catalina Sky Survey and Spacewatch, include the Magdalena Ridge Observatory in New Mexico and the Astronomical Research Institute near Charleston, Illinois. A good number of these follow-up observations are provided by the international community of professional and amateur astronomers. NASA-funded observational programs to study the physical characteristics of NEOs include optical, infrared and radar observation techniques.
Established in July 1998, NASA's NEO Program Office at JPL (http://neo.jpl.nasa.gov) receives astrometric data and preliminary orbits from the Minor Planet Center and then continuously improves these orbits, and the resulting close Earth approach predictions, as additional data are received. Once a new orbit has been successfully fitted to the available observational (astrometric) data, the object's trajectory is numerically integrated forward in time to note any close Earth approaches in the next 100 years. Those objects for which an Earth impact cannot yet be ruled out are automatically submitted to the SENTRY system for further risk analysis. An independent impact monitoring effort is conducted in parallel by colleagues at the University of Pisa and at the University of Valladolid Spain. In parallel with the NASA-supported NEO Program Office activities at JPL, our European colleagues also run a sophisticated impact monitoring system called NEODyS/CLOMON) that is independent of the JPL effort (http://newton.dm.unipi.it/cgi-bin/neodys/neoibo).
Some of the most recent achievements of the NEO Program Office personnel include:
1. The rapid and successful prediction of the small (few meter-sized) Earth impacting asteroid 2008 TC3 on October 7, 2008 at 02:46 UT over northern Sudan [http://neo.jpl.nasa.gov/news/news160.html]. This dramatic prediction of an actual impact underscored the success of the current NEO discovery and orbit prediction process. The discovery was made by the CSS, observations were provided by 26 international observatories, the orbit and impact computations were determined, verified and announced well before the impact, which took place only 20.5 hours after the discovery itself.
2. The successful prediction of an Earth close approach to within 1.4 lunar distances (554,200 km) by the near-Earth object 2007 TU24 on 2008 January 29 - an object whose diameter is approximately 330 meters.
3. The successful prediction of a Mars close approach to within 26,000 km by the 50 meter-sized, near-Earth asteroid 2007 WD5 on 2008 January 30.