Asteroid Terrestrial-impact Last Alert System
||This article needs to be updated. (February 2016)|
The Asteroid Terrestrial-impact Last Alert System (ATLAS) is an astronomical survey system for detection of dangerous asteroids a few weeks to days before their impacting Earth. The project was developed at the University of Hawaii with US$5 million funding from NASA.
With its first element deployed in 2015, the automated system provides a one-week warning for a 45 metres (150 ft) diameter asteroid, and a three-week warning for a 120 m (390 ft) one, as long as their radiant is not too close to the Sun. By comparison, the February 2013 Chelyabinsk meteor impact was from an object estimated at 17 m (60 ft). Its radiant's closeness to the Sun put it in the blind zone of an ATLAS-like system, but a similar object arriving from a dark direction would be detectable approximately one day in advance.
The first telescope became fully operational at the end of 2015 and the second one in March 2017. ATLAS may be expanded geographically to several other locations in both hemispheres to provide continuous coverage, resilience to bad weather, and additional information on the orbit from the parallax effect. Additionally, ATLAS looks for dwarf planets, non-impacting asteroids, and supernovae.
The Last Alert part of the system name refers to the fact that ATLAS will find smaller asteroids much too late in time for potential deflection, but that the days or weeks of warning that would be provided are enough to evacuate and otherwise prepare a target area. According to ATLAS project lead John Tonry, "that's enough time to evacuate the area of people, take measures to protect buildings and other infrastructure, and be alert to a tsunami danger generated by ocean impacts". Much of the damage and injuries caused by the Chelyabinsk meteor impact were from window glass broken by its shock wave, and with advance warning those could have been much reduced by actions as simple as propping all windows open before the impact.
Design and operation
The full ATLAS concept consists of eight 50cm diameter telescopes, each fitted with cameras with resolution of 100 megapixels, spread over the globe for full sky coverage. The first two telescopes, ATLAS1 and ATLAS2, are sited on Haleakala and Mauna Loa in the Hawaiian Islands and are operational. Each telescope scans the visible sky twice per night, much more quickly but in much less depth than larger surveying telescope arrays such as University of Hawaii's Pan-STARRS.
NASA's Near Earth Observation Program initially provided a US$5 million grant, with $3.5 million covering the first three years of design, construction and software development, and the balance of the grant to fund the systems operation for two years following its entry into full operational service in late 2015. A further NASA grant funds continued operation of ATLAS until 2021. 
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- University of Hawaii at Manoa's Institute for Astronomy (18 February 2013). "ATLAS: The Asteroid Terrestrial-impact Last Alert System". Astronomy Magazine. Retrieved 2013-02-22.
- Atlas: How it works. Asteroid Terrestrial-impact Last Alert System.
- Clark, Stuart (18 February 2013). "Asteroids and how to deflect them". The Guardian. Retrieved 2013-02-22.
- ATLAS Telescope 2 Installed on Mauna Loa, Ari Heinze  Retrieved April 7, 2017.
- Oliver, Chris. ATLAS Project Funded by NASA, Nā Kilo Hōkū (newsletter), Institute for Astronomy, University of Hawaii, No. 46, 2013, p. 1. Retrieved August 2, 2014.
- ATLAS Update #18: 2017 March  Retrieved April 14, 2017.