NASA made its decision because of being inadequately funded to meet a congressionally mandated goal of detecting all objects larger than one kilometer in near-Earth orbits by 2008.

"Arecibo radar observations are crucial for determining the exact location, speed and direction of objects that approach Earth," said Louis Friedman, Executive Director of The Planetary Society. "We need this information to know how significant the probability is of any one asteroid hitting the Earth. It is irresponsible for Congress to mandate that NASA undertake asteroid and comet detection, and then to not provide sufficient funds for that program."

The Arecibo Observatory in Puerto Rico and the Goldstone Tracking Station in Barstow California, which is part of the Deep Space Network, are the only two radar sites capable of asteroid observations. Goldstone is not as powerful as Arecibo and is very busy supporting spacecraft missions.

The funding problem arose when funds to provide facility support at Arecibo had to be taken out of the asteroid observation program in NASA. That program includes the high-priority optical telescope searches for Near-Earth Objects, a class of bodies that includes asteroids and comets whose orbits carry them close by our planet.

Radar observations provide the very accurate position and velocity information necessary to determining the orbits and predicting the future paths for the objects that come very close to Earth.

"The decision to eliminate these Arecibo observations, and not obtain precision data, is very short-sighted," commented Friedman. "If an object is discovered headed to Earth, we are certainly going to wish we had the ability to track it accurately."

In addition to providing detailed position and velocity information, the Arecibo observations also are often the only way to characterize the NEO's shape and rotation. This information is critical to the science of NEOs, and to understanding their origin and evolution, and the important role they have played in the evolution of terrestrial planets.

A NEO that struck the Earth 65 million years ago triggered the extinction of the dinosaurs and most species then flourishing.  Another such object could come our way at any time.