Little telescope to hunt big game: hard-to-see near-Earth asteroids
Canada's NEOSSat space telescope was launched Monday atop an Indian rocket. It will monitor two groups of asteroids whose proximity to the sun makes them hard to see from Earth.
Efforts to discover near-Earth asteroids – including those that are potentially hazardous – received a potential boost Monday with the launch of the Canadian Space Agency's Near Earth Object Surveillance Satellite (NEOSSat).Skip to next paragraph
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Housed in a spacecraft the size of a large suitcase, the space telescope physically is a munchkin among behemoths. Its light-gathering mirror is only about 6 inches across.
But from its orbit nearly 500 miles above Earth, NEOSSat will be able to view faint near-Earth asteroids in a region of space that is tough for terrestrial telescopes to tackle.
The $25 million NEOSSat mission is one of seven satellites the Indian Space Agency lofted Monday aboard a single rocket launched from the Satish Dhawan Space Center, some 50 miles north of Chennal, on India's east coast.
To date, astronomers say they have discovered between 90 and 95 percent of the approximately 1,000 near-Earth asteroids estimated to be larger than half a mile across.
In 2005, Congress instructed NASA to hunt for smaller asteroids – setting a goal of finding 90 percent of near-Earth asteroids 500 feet wide and larger by 2020.
But as the Chelyabinsk asteroid demonstrated on Feb. 15, objects far smaller can inflict damage. At about 55 feet across, and with a mass estimated at 10,000 tons, the asteroid exploded high over the Ural mountains. The shock waves damaged an estimated 4,300 buildings and injured nearly 1,500 people.
With tens of millions of objects this size orbiting the sun, the recurrence rate for collisions with a Chelyabinsk-like object averages once every 100 years, according to Paul Chodas, with NASA's Near-Earth Objects Program Office at the Jet Propulsion Laboratory in Pasadena, Calif.