Scientists think they may be on the verge of understanding how gaseous pollutants work their way through the upper atmosphere and so affect life on Earth.
The advance will be one of several important sets of results to emerge this week from a meeting in Italy to evaluate the maiden mission of Spacelab, the world's first reusable space laboratory.
Researchers from Western Europe, the United States, and Japan are convening in Capri June 13 to 15 to announce preliminary findings from the 10-day mission, which took place at the end of last year.
Spacelab, a canister with room for several people plus scientific hardware, was carried aloft inside the cargo bay of a US space shuttle. The laboratory was built by a consortium of 11 West European nations for $750 million. After the mission, however, which was organized jointly by NASA and the European Space Agency, the lab became the property of the US government.
The mission provided an opportunity for about 70 experiments in areas ranging from material science to biology. Scientists inside Spacelab either tested specimens to evaluate their behavior in zero gravity or used the laboratory as a platform from which to take measurements of the Earth or its atmosphere.
Researchers are particularly pleased with results from instruments that scanned the upper part of the atmosphere as Spacelab orbited the Earth. In these experiments, coordinated by Utah State University and the Institut d'Aeronomie Spatiale de Belgique in Brussels, scientists made the first detailed measurements of trace gases found in the atmosphere between 25 and 60 miles above the Earth. Before the flight, researchers had only a poor understanding of this part of the atmosphere.
The Spacelab hardware obtained readings of gases such as methane, carbon dioxide, carbon monoxide, and ozone. By repeating the experiments on later Spacelab flights, scientists may be able to keep track of gaseous pollutants and build up models for the ways in which the materials disperse naturally through the atmosphere.
Workers may also find they can monitor in detail variations in the ozone layer. Any changes in this layer may affect life on Earth as the gas acts as a barrier to harmful rays from the sun.
In another study, workers from the University of Freiburg, West Germany, organized an experiment to grow large protein crystals of the kind used as biochemical catalysts. On Earth, it is difficult to extract such crystals from solutions - thermal effects not present in the zero gravity of space flight destroy the bonds before they can form properly. The researchers made crystals just a few millimeters in diameter. Even so, they are up to 1,000 times bigger than those made in Earth-bound laboratories.
The Freiburg workers also turned out silicon crystals to a far higher quality than that obtained on Earth. In the future, space laboratories could produce such materials in large quantities for high-performance silicon chips that are free from structural defects.
Scientists on Spacelab produced other results that could help in the design later this century of nuclear-fusion reactors to produce energy. From the laboratory, astronauts shot into space beams of electrons and then collected them, with the metal parts of the shuttle acting as a conductor.
Surprisingly, they found that the energy of the beam increased fivefold. Researchers think the electrons obtained the extra energy from the plasma, or ''soup'' of ionised gases, that is present at the altitude at which the shuttle flies. The plasma is similar to the ionized gases inside fusion reactors on engineers' drawing boards. Experiments of this kind could help researchers work out operating conditions for such hardware.
The Spacelab experiments also shed some light on ways to improve the health of astronauts while they are in space. People traveling above the atmosphere often say they suffer from severe illness during the first few days of their journey. The Spacelab workers think they have pinned this down on erratic behavior of the organ in people's ears responsible for their sense of balance.
In another experiment, scientists think they have discovered why people returning from space sometimes suffer from anemia. They believe that the weightless conditions of space fools the body into destroying more blood cells than is good for the astronaut's health.
The first Spacelab flight cost $350 million, including launch fees. But NASA thinks that in a few years, the cost of each mission could come down to as little as $75 million, as a result of better experience with using Spacelab and reduced launch costs. NASA hopes to fly Spacelab on average once a year, with the next mission, to concentrate on materials science, due this fall.