Editor’s note:
Star science reporter Dan Sorenson and higher education reporter Eric Swedlund have spent two months researching and reporting for a three-day series about space sciences at the University of Arizona and across the state. The Star’s three-day special report begins Sunday, complete with exclusive online-only content. Along the way our reporters interviewed dozens of scientists in Tucson, Tempe and Flagstaff and as a preview to the series, will introduce you to some of the researchers, programs and missions daily on this blog.

A team of UA astronomers has created the leading survey for near-Earth objects, using two telescopes in the Catalinas and one in Australia to scan for asteroids or comets that may be capable of striking Earth. As one of five surveys in NASA’s Spaceguard program, which was mandated by Congress in 1998, the Catalina Sky Survey, led by Steve Larson, has discovered 73 percent of all near-Earth objects found in the last six months.

The program was created to catalog and track at least 90 percent of the near-Earth objects, objects that pose potential danger to Earth. Scientists haven’t yet spotted anything on a collision course with Earth, but in 2029 the 320-meter wide asteroid 2004 MN4 is expected to make a very close approach to Earth, missing by 18,600 miles, within the orbit of geosynchronous satellites.

Since the surveys began, the number of known asteroids has increased from 20,000 to more than 300,000 now. The surveys have discovered almost 4,700 near-Earth objects, including 715 asteroids 1 km or greater in diameter.

Larson attributes the UA’s success, finding 904 near-Earth asteroids since 2005, to the ability to use complementary telescopes, one with a wider view and one that can see fainter objects, that scan similar volumes of space.

“Ideally what a survey should do is look at as much sky as often as possible,” Larson says. “There’s a trade off between having a large field and the ability to go faint, but we have a good combination to survey and find these things.”