Earth is occasionally struck by an asteroid or comet large enough to cause a significant explosion and loss of life. The most likely impact is by a relatively small object and the best mitigation…

This is a grant awarded by the National Aeronautics and Space Administration (NASA) to the University of Hawaii at Manoa to operate the Asteroid Terrestrial-Impact Last Alert System (ATLAS), an early warning system that can detect asteroids and comets on track to impact the Earth. The $2,225,035.96 grant will fund the continued operation of two existing ATLAS observatories and the construction of two additional observatories in the Southern Hemisphere. ATLAS is designed to provide 3 weeks of warning for asteroids larger than 140 meters and 1 week of warning for those larger than 50 meters, enabling evacuation of affected areas. The grant supports ATLAS's objectives to rediscover existing near-Earth objects, discover new ones, and characterize their properties. This grant does not have a set-aside designation. The University of Hawaii System, a state-controlled public higher education institution, is the prime contractor.

Earth is occasionally struck by an asteroid or comet large enough to cause a significant explosion and loss of life. The most likely impact is by a relatively small object and the best mitigation strategy may simply be to move people out of the way. With enough warning, a small asteroid impact would not cause loss of life, and portable property might even be preserved. We have built an "early warning" system that provides a three week notice of most 140M asteroids or comets on track to HIT the earth, and a week's notice for most 50M asteroids. The system has been designed, built, and brought into operation in less than three years, and is easily replicable. The "asteroid terrestrial-impact last alert system" (atlas), currently comprises two observatories separated by about 100KM that can scan the entire visible sky more than twice a night to magnitude 20. Software automatically registers comparisons with the unchanging sky and identifies everything that has moved or changed. Communication between the observatories and the IAU minor planet center locks down the orbit of anything approaching the earth. This proposal seeks funding to continue operations of the two atlas units already built and to construct two more units for the southern hemisphere. Atlas is complementary to many existing surveys for near-earth objects (neos) by virtue of being all-sky: IT can detect most 140M neos that pass within 0.1AU of the earth. Atlas may find more than 500 neos per year, even though its forte is discovery of the subset of neos that pass very close to the earth. Its steady sky coverage is also valuable for discovery of low delta-v asteroids, candidate targets for a manned mission. Furthermore, atlas will characterize the NEO population and all the other objects IT detects by obtaining hundreds of light curve points per year that will enable the determination of their shape and spin and also by obtaining simultaneous color measurements. Objectives: atlas will 1) provide warning that is useful on a civil defense timescale for the majority of earth-impacting asteroids of 50M size or larger, 2) rediscover 50% of all 1000M neos and potentially hazardous objects (PHO) within 1 year, 70% in 3 years, and 90% in 10 years, discover more than 400 neos and 100 phos per year of 140M size or larger, 3) detect about one small asteroid per year that hits the earth, 4) discover low delta-v asteroids, 5) enable shape and spin calculations from hundreds of observations per year of thousands of asteroids, and 6) detect all pluto-sized objects within a distance of 120 AU. Methods: we have built a pair of small observatories each with an 0.5M telescope that covers 30 square DEG with each exposure, and we have written all the software required for them to operate without human intervention. We are currently reporting asteroid and comet detections to the MPC, and as the system comes fully online our rate of discovery will increase by a factor of 10. By building another two units in the south and at different longitude we will double our detection probability for the next chelyabinsksized impactor. Significance: this project works towards accomplishing the congressional mandate to mitigate the hazard from earth-impacting asteroids by focusing on detection of nearly all hazardous asteroids in the days or weeks before impact. Although detection in time to divert dangerous asteroids is laudable, IT is also currently unaffordable, and atlas addresses the intent of the mandate by protecting lives. Atlas will afford a yearly opportunity to study a meteorite before IT strikes the earth's atmosphere, and will provide much better statistics on the population that does pass close to the earth. Atlas will discover low delta-v asteroids suitable for a manned mission, and characterization of the spin and shape of many asteroids may prove valuable for future missions.