For Release: April 13, 1995

Steve Roy
Marshall Space Flight Center
Huntsville, Ala.
(205)544-6535

RELEASE NO: 95-30

NASA INSTRUMENT MAKES FIRST QUANTITATIVE LIGHTNING MEASUREMENT FROM SPACE WITH PINPOINT ACCURACY

NASA 's Optical Transient Detector is pinpointing atmospheric lightning with unprecedented accuracy and sensitivity, following its recent launch and activation.

"We've begun the process to build and archive a worldwide lightning data base and contribute that information to a better understanding of the Earth's atmospheric system," said Principal Investigator Dr. Hugh Christian of the Marshall Space Flight Center's Global Hydrology and Climate Center in Huntsville, Ala.

The Optical Transient Detector is a highly compact instrument which detects instantaneous changes in light intensity in its field of view, day or night. These momentary changes are an indication of the occurrence of lightning.

The instrument was carried into Earth orbit April 3 on a Pegasus launch vehicle provided by Orbital Sciences Corporation. Activation and checkout were completed April 11.

Initial operations are now focusing on evaluation and analysis of early observations by the instrument, gathered as it circles the Earth approximately every 100 minutes at an altitude of 459 statute miles (738 kilometers).

"We are very excited about the preliminary results from the instrument," said Christian. "We're receiving high quality images of cloud formations and detecting lightning events." The focus of activity during the next few weeks will be on evaluation of initial data and building familiarity with the routine operations of the detector, Christian said . "Further, we plan to compare lightning data with both ground measurements and observations from other satellites. The lightning detector team is off to a great start," said Christian.

"This success is the result of the extremely hard work of some highly dedicated MSFC employees who developed this scientific instrument in a short period of time," said Project Manager Roger Chassay of the Science and Applications Office. We're very proud of their efforts and we also appreciate the fine efforts of the Orbital Sciences Corporation team who got our payload into orbit, Chassay said. "Now we are excited about the lightning data which we will be receiving now that the OTD is in orbit. This will provide information on the global distribution of lightning during daytime as well as night," said Chassay.

The Optical Transient Detector Project is managed by the Marshall Center.