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Contact: Jim Doyle

FOR IMMEDIATE RELEASE                                                 June 23, 1993

       NASA Jet Propulsion Laboratory scientists said today a new recording instrument saved important atmospheric observations taken aboard an early April shuttle flight despite problems with the shuttle's telemetry system.

       Scientists on the Atmospheric Trace Molecule Spectroscopy (ATMOS) project said the data on gases which may harm the ozone level were captured on a new on-board data recovery system.

       ATMOS measures the abundance of between 30 and 40 atmospheric gases in the middle atmosphere. The instrument has been flown aboard the shuttle three times but it was the first flight for the ATMOS recorder subsystem.

       It also was the first time ATMOS had looked at gases which may affect ozone in the northern hemisphere. ATMOS flew aboard NASA's second Atmospheric Laboratory for Applications and Science (ATLAS-2) Spacelab mission.

       When the shuttle's telemetry system, which would have downloaded ATMOS data in real time, ran into problems, the new recorder was used to store the data. Early last week, the data tape was played back for the first time at JPL; the quality was found to be excellent.

       The new recorder subsystem has a 44-gigabyte (353 billion bits) storage capacity which allowed the recording of more than half of the ATMOS observations -- nearly 6-1/2 hours of data -to be saved.

       Assistant Project Manager Greg Goodson said the data they saved are excellent and analysis is underway. Results are expected to be published soon, he said, which will present a better understanding of the gases which damage the northern hemisphere ozone layer.

       All ATMOS data are normally transmitted to the payload operations center through the shuttle's high data rate telemetry system. On the ATLAS-2 mission, problems developed with the shuttle's telemetry system which prevented the transmission of most of the live ATMOS data.

       NASA worked out a program during the problem period which allowed some ATMOS data to be recorded on the Spacelab's high data rate recorder and dumped at a reduced rate. Unfortunately the data were contaminated with noise, project officials said, and as a result less than 25 percent was of scientific value.

       The ATMOS recorder subsystem, a separate, dedicated data recording system developed by the ATMOS team at JPL, was able to save the atmospheric observations, however, Goodson said.


6/23/93 JJD