Space sciences '91: NASA looks for a brighter new year - includes month-by-month list of upcoming space missions

Science News, Jan 12, 1991 by Jonathan Eberhart

On its way, Galileo will pass "minor planet" Gaspra. This rocky asteroid seems unlikely to prove a star of the mission, since the limited spectral measurements available from Earth suggest it is just a chunk of stone some 15 km across. Galileo should whip by Gaspra at a relative top speed of more than 28,800 km per hour, taking pictures and spectral measurements as it passes within 1,600 km of the asteroid's surface.

The spacecraft will continue along a circular route carrying it past Earth again on Dec. 8, 1992. After this second, accelerating rendezvous with its home planet, Galileo will finally head for Jupiter, possibly passing a second asteroid named Ida along the way.

* The protective ozone layer in Earth's upper atmosphere -- imperiled by some chemicals including the chlorofluorocarbons -- will be the focus of the Upper Atmosphere Research Satellite (UARS), set for release from the shuttle Discovery in November. Expected to operate for three years, UARS will carry nine instruments to compile a planet-wide data base about the chemistry and motions of the upper atmosphere, the effects of the sun's radiation on the upper atmosphere, and changes in the amount and distribution of ozone and other atmospheric gases.

* In December, the shuttle Atlantis will carry the International Microgravity Laboratory aloft to study how the reduced gravity of space affects the properties of different materials and the workings of mechanical devices. NASA hopes the microgravity study will, like Columbia's biomedical mission in May, help write the textbooks for astronauts working on space station Freedom. The European Space Agency, France's National Center of Space Studies, the National Research Council of Canada, Japan's National Space Development Agency and the German Aerospace Research Establishment helped NASA develop the mission.

Scientists continue to await the detection -- which may or may not occur this year -- of the shock wave formed where the solar wind collides at supersonic speed with a similar flow of charged particles coming in from other stars. The only craft that might do the job are Voyagers 1 and 2 and Pioneers 10 and 11. Launched between 1972 and 1977, all four are now headed away from the sun toward an invisible zone called the hellopause -- a region that some scientists define as the true edge of the solar system.