New information on the materials that make up the structure of asteroid families will be presented by Shelte Bus of the Massachusetts Institute of Technology at a press conference Tuesday, the second day of the International Asteroids, Comets and Meteors Conference (ACM) at Cornell University.

Bus will present observational results for objects in different regions of the solar system at one of the daily press conferences (Tuesday, July 27, 12:30 p.m., 109 Ives Hall). He will moderate a discussion of new results from a spectroscopic survey of asteroids in the main belt (located between the orbits of Mars and Jupiter), where it is found that collisions between the asteroids have played a major role in their evolution. He also will discuss the outermost observable part of the solar system, extending to the recently discovered Kuiper Belt, and objects called Centaurs, thought to be leftover fossils from the early formation of the solar system.

Due to their small sizes and great distance from the sun, these objects are the most challenging to observe. Measurements of their colors reveal significant variations between the individual bodies, suggesting that processes, which as yet are not understood, are at work in this coldest region of the solar system.

Spectroscopy is the technique of breaking light into its component colors, or spectrum, and measuring the amount of each color that is present. Since different materials reflect (or emit) light in different ways, the spectrum of an object is like a fingerprint of the material making up that object.

At another press conference, (Thursday, July 29, 10 a.m., 109 Ives Hall) Peter Jenniskens of NASA/Ames, will discuss the mixed results from last fall's observation of the Leonid meteor shower, which occurs each November 12. Jenniskens is the leader of NASA's multinational airborne study of the shower, the Leonid Multi-Instrument Aircraft Campaign.

Meteor showers occur when Earth passes through a comet's path. The Leonid shower is associated with comet Tempel-Tuttle (orbital period 33.5 years). Meteors, popularly called "shooting stars," are the flashes of light caused by pea-sized bits of comets that slam into the Earth's upper atmosphere at 25,000-160,000 miles an hour.

Researchers call the current era the golden age of comet and asteroid exploration. And at a press conference (Wednesday, July 28, 10 a.m., 109 Ives Hall) Donald K. Yeomans, supervisor, Solar System Dynamics Group at NASA's Jet Propulsion Laboratory will moderate a discussion of detailed investigations of 13 different comets and asteroids by at least seven spacecraft within the next 12 years.

Although it was designed primarily to test new technologies in space, the New Millennium Deep Space 1 (DS1) mission will fly close to, and image, asteroid 1992 KD on July 29, 1999. It is hoped that DS1 will then be targeted to fly close to asteroid Wilson-Harrington and comet Borrelly in January and September of 2001.

Beginning on Valentine's Day, 2000, the NEAR spacecraft will spend nearly a year in close orbit about the asteroid Eros, making detailed mapping and chemical analysis. In a Japanese and American cooperative effort, the MUSES-C mission will land upon asteroid 1989 ML in October 2003 and deploy a book-sized rover to study the asteroid's surface and chemical composition. The Muses-C spacecraft will also collect surface samples and bring them back to Earth in June 2006 for study.

A few months earlier, in January 2006, the Stardust mission will return a sample of cometary dust to Earth for analysis. The Stardust mission will fly past comet Wild 2 in January 2004, collect dust particles and provide images of the comet's nucleus. Between November 2003 and August 2008, the Contour mission will fly past and scrutinize three widely diverse comets (Encke, Schwassmann-Wachmann 3, d'Arrest) and if a bright new comet is discovered in time, Contour could be diverted to intercept it.

The recently selected Deep Impact Discovery mission will release a 500 kilogram (1,110 pounds) impactor that will strike comet Tempel 1 on July 4, 2005, and then study the resulting crater and ejecta as the spacecraft flies by. This will be the first experiment to study the subsurface cometary regions. After flying by two asteroids en route, the European Space Agency's Rosetta spacecraft will rendezvous and land upon comet Wirtanen in November 2011. The nucleus of this comet will then be subjected to a wide variety of scientific studies to determine its nature and composition.