As of the end of 2003, the Spaceguard Survey had discovered just over 700 near-Earth asteroids larger than 1 km wide. Current estimates put the total number of such objects at about 1,000 — give or take 100 — so we’re about 70 percent there. At the present discovery rate, Spaceguard should reach the 90-percent mark in late 2008 or 2009 — on schedule and within budget.
The 60-centimeter Uppsala Schmidt telescope at Siding Spring Observatory in Australia has been hunting asteroids since upgrades were completed in March 2004. Known as the Siding Spring Survey, it forms a southern complement to the Catalina Sky Survey operated by the Lunar and Planetary Laboratory at the University of Arizona.
NASA funds the North American programs, which have made about 87 percent of the discoveries so far, as well as the Siding Spring Survey. — BILL COOKE, MARSHALL SPACE FLIGHT CENTER