NEAR-Shoemaker

Near Earth Asteroid Rendezvous - Shoemaker

Dr. Lucey's interest in asteroids has focussed on the effect of temperature on the reflectance spectra of asteroids. Measurements made at HIGP in the mid-80's showed that reflectance spectra of minerals thought to be common on asteroids, and known to be common on meteorites we think are derived from asteroid, vary systematically with temperature. Dr. Lucey found that the spectra of the A-type asteroids (obtained at the NASA Infrared Telescope Facility), which have spectra very similar to the spectrum of the mineral olivine, are most similar to spectra of olivines obtained at very low temperatures. The A-asteroids are far from the Sun and are expected to have cold surface temperatures. Following this finding Dr. Lucey constructed a spectral measurement facility designed to carefully measure the effect of temperature on spectra of minerals, meteorites and lunar samples and this facility is yielding a wealth of data on this topic.

These temperature effects are the focus of Dr. Lucey's science investigation on the NEAR mission to the asteroid Eros. He intends to use changes in the spectra of locations on the asteroid as the time of day changes to measure the change in temperature with local time of day. If the asteroid surface is solid rock, it will tend to change in temperature very slowly and weakly with local time of day. If the temperature changes rapidly with local time of day, then the surface is probably covered with fine powder, technically called a regolith.