Nov 1 1985
From The Space Library
Jet Propulsion Laboratory (JPL) planetary scientist Steve Ostro recently completed a five-year study of asteroids located in a belt between the orbits of Mars and Jupiter, the JPL Universe reported, and then turned his attention to observing near-earth asteroids using the world's most powerful radar telescope at the Arecibo Observatory in Puerto Rico.
"Some asteroids are among the most primitive planetesimals-the matter which accreted to form the solar system," Ostro said. "Asteroids are every bit as exciting as comets and potentially the most important objects in our solar system," he pointed out.
Asteroids constituted an enormous and diverse population, ranging in size from a few hundred meters to 1,000 km, and varying in composition, spin rate, and shape. Most asteroids were in the belt Ostro had studied and were thought to be the remnants of a planet that failed to form due to Jupiter's gravitational influence. However, many other asteroids tumbled through space close to and sometimes across earth's orbit.
Some scientists believed near-earth asteroids could be the nuclei of burned-out comets. "We really don't know what the nucleus of a comet is," Ostro said. "Comets might eventually lose all of their volatile compounds and then travel as asteroids." And scientists believed asteroids were some of the most primitive objects in the solar system. "We really have a spectrum of asteroids-some of the primitive material left from the solar nebula all the way up to those that are highly evolved," Ostro commented. "So asteroids are a laboratory for studying the evolution of planets and other planetary objects." No spacecraft had ever explored an asteroid, nor had scientists obtained an image of an asteroid's surface. That was why many planetary scientists believed JPL's proposed Comet Rendezvous/Asteroid Flyby mission was critical to understanding not only comets and asteroids, but also the history of the solar system.
Another JPL planetary scientist, Eleanor Helin, recently discovered a near-earth asteroid with a 36-inch telescope located in Caussols, France. The asteroid, designated 1985-PA and the 22nd asteroid discovered by JPL researchers, had a small elongated orbit highly inclined to the ecliptic plane; scientists had discovered only two other near-earth asteroids with orbital inclinations higher than 1985-PA. Helin said the asteroid's inclination suggested it could have had a close encounter with Mars and been knocked into the steeply inclined orbit.
At discovery the asteroid was moderately bright-measuring at 16.5 magnitude-and reddish, indicating the asteroid was probably a stony, silicaceous body. (JPL Universe, Nov 1/85, 1 and 2)
The U.S. Air Force's Electronic Systems Div. awarded Grumman Corp. a $657 million contract to build the Joint Surveillance Target Attack Radar System USTARS), an airborne radar system for spotting tanks, personnel carriers, or any other enemy vehicle moving or standing still, the Air Force Systems Command (AFSC) Newsreview reported. A C-18, a militarized version of Boeing's 707, would serve as the radar's airborne development platform. The JSTAR would include radar equipment and operations and control displays as well as communications links to ground terminals and weapons systems.
Under the fixed-price incentive contract, a Grumman team including Boeing Military Airplane Co. and United Technologies Corp.'s Norden Systems Div. would design, build, and test two full-scale-development airborne radar systems. The Air Force and Army would test the JSTARS ability to detect, locate, and track enemy ground vehicles and to help ground commanders plan attacks to destroy them. The Air Force expected field testing to begin in March 1990.
Col. Harry Gillogly, JSTARS program manager, said the airborne systems would provide "an electronic high ground to observe maneuvering enemy forces," telling Air Force and Army commanders what forces to apply where and when in order to inflict the most damage at the least cost.
"Both services will be able to attack key targets," Gillogly said, "the Air Force with direct-attack aircraft and missiles, and the Army with artillery, maneuver forces, and ground-launched missiles." (AFSC Newsreview, Nov 1/ 85, 1)
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