||During the 1970s, NASA's planetary science budget shrank, and JPL Director Bruce Murray expanded the lab's research horizons to preserve its technological capabilities. JPL took on new tasks in Earth science and astronomy, while continuing its leading role in planetary exploration with two key efforts, the Viking missions to Mars and the Voyager missions to the outer planets.
Studying Earth's Ozone
In the 1970s and 1980s, a major scientific controversy erupted over chlorofluorocarbons, the chemicals released by spray cans, refrigerators and air conditioners. Could these compounds be destroying Earth's stratospheric ozone layer, which protects against harmful solar radiation?
In 1974, JPL Chief Scientist Moustafa Chahine wanted to help resolve this question. He established several instrument development efforts aimed at measuring chlorofluorocarbons and their breakdown products. These resulted in the Space Shuttle-based Atmospheric Trace Molecule Spectroscopy Experiment, and the Microwave Limb Sounders on the Upper Atmosphere Research Satellite and aboard the more recent Aura mission. Chahine's efforts also inspired a series of balloon- and aircraft-based instruments that JPL scientists took on field expeditions to the Antarctic and Arctic .
These experiments helped show that stratospheric ozone depletion was a complex process involving chlorofluorocarbons, stratospheric clouds and extremely low temperatures. In 1987, diplomats from most of the world's nations met in Montreal , Canada , to negotiate a mandatory reduction in chlorofluorocarbon production in response to NASA's 15 years of evidence. In 1992, the resulting Montreal Protocol was further tightened to ban production of these chemicals entirely. JPL's Microwave Limb Sounder on the Aura satellite still monitors stratospheric health.