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Contact: Mary A. Hardin

FOR IMMEDIATE RELEASE                                                April 15, 1993

       Scientists at NASA's Jet Propulsion Laboratory report the successful flight of a balloon carrying instruments designed to measure and study chemicals in the Earth's ozone layer.

       The April 3 flight from California's Barstow/Daggett Airport reached an altitude of 37 kilometers (121,000 feet) and took measurements as part of a program established to correlate data with the Upper Atmosphere Research Satellite (UARS).

       The data from the balloon flight will also be compared to readings from the Atmospheric Trace Molecular Spectroscopy (ATMOS) experiment which is currently flying onboard the shuttle Discovery.

       "We launch these balloons several times a year as part of an ongoing ozone research program. In fact, JPL is actively involved in the study of ozone and the atmosphere in three important ways," said Dr. Jim Margitan, principal investigator on the balloon research campaign.

       "There are two JPL instruments on the UARS satellite," he continued. "The ATMOS experiment is conducted by JPL scientists, and the JPL balloon research provides collaborative ground truth for those activities, as well as data that is useful in its own right."

       The measurements taken by the balloon payload will add more pieces to the complex puzzle of the atmosphere, specifically the mid-latitude stratosphere during winter and spring. Understanding the chemistry occurring in this region helps scientists construct more accurate computer models which are instrumental in predicting future ozone conditions.

       The scientific balloon payload consisted of three JPL instruments: an ultraviolet ozone photometer which measures ozone as the balloon ascends and descends through the atmosphere; a submillimeterwave limb sounder which looks at microwave radiation emitted by molecules in the atmosphere; and a Fourier transform infrared interferometer which monitors how the atmosphere absorbs sunlight.

       Launch occurred at about noontime, and following a threehour ascent, the balloon floated eastward at approximately 130 kilometers per hour (70 knots). Data was radioed to ground stations and recorded onboard. The flight ended at 10 p.m. Pacific time in eastern New Mexico when the payload was commanded to separate from the balloon.

       "We needed to fly through sunset to make the infrared measurements," Margitan explained, "and we also needed to fly in darkness to watch how quickly some of the molecules disappear."

       It will be several weeks before scientists will have the completed results of their experiments. They will then forward their data to the UARS central data facility at the Goddard Space Flight Center in Greenbelt, Maryland for use by the UARS scientists.

       The balloon was launched by the National Scientific Balloon Facility, normally based in Palestine, Tex., operating under a contract from NASA's Wallops Flight Facility. The balloon was launched in California because of the west-to-east wind direction and the desire to keep the operation in the southwest.

       The balloons are made of 20-micron (0.8 mil, or less than one-thousandth of an inch) thick plastic, and are 790,000 cubic meters (28 million cubic feet) in volume when fully inflated with helium (120 meters (400 feet) in diameter). The balloons weigh between 1,300 and 1,800 kilograms (3,000 and 4,000 pounds). The scientific payload weighs about 1,300 kilograms (3,000) pounds and is 1.8 meters (six feet) square by 4.6 meters (15 feet) high.

       The JPL balloon research is sponsored by NASA's Upper Atmosphere Research Program and the UARS Correlative Measurements Program.


4/15/93 MAH