Monday, Dec. 8, 1997

2 p.m. EST

The Tropical Rainfall Measuring Mission (TRMM) operations continue to go according to plan and no problems are reported after 11 days on-orbit.

"We are very pleased with the mission to date," said Tom LaVigna, TRMM project manager at NASA’s Goddard Space Flight Center, Greenbelt, Md. "We anticipate the release of the first data from two of the instruments within a few days."

This past Tuesday, the last instrument to be turned on, CERES, was activated and checkout is continuing. On Wednesday, the first of several orbit adjust maneuvers was performed as controllers fired the propulsion thrusters. The last of these descent maneuvers was completed on Sunday and culminated with TRMM arriving at its nominal circular orbit of 217 miles (350 kilometers) on Sunday at 2:29 p.m. EST.

With the observatory at its operational orbit, detailed checkout of the Precipitation Radar (PR) instrument has now begun. The PR is the first spaceborne radar ever and was provided by the National Space Development Agency of Japan.

The first space mission dedicated to studying tropical and subtropical rainfall launched Thanksgiving day from the Japanese Space Center, Tanegashima, Japan. TRMM lifted off at 4:27 p.m. EST on a Japanese H-II rocket and just fourteen minutes later, TRMM separated from the rocket’s second stage. The automatic sequencer on TRMM successfully deployed the solar arrays, and the high gain antenna after a short time-out period initiated at separation.

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The TRMM satellite was built as an in-house project at NASA Goddard and launched by the National Space Development Agency of Japan. NASDA provided one of the five instruments - the Precipitation Radar. NASA’s Marshall Space Flight Center provided the Lightning Imaging Sensor and the Langley Research Center provided the CERES instrument while Goddard provided the remaining two instruments - TMI and the Visible Infrared Scanner.

The primary objective of the TRMM program is to obtain and study multi-year science data sets of tropical and subtropical rainfall measurements; to understand how interactions between the sea, air and land masses produce changes in global rainfall and climate; to improve modeling of tropical rainfall processes and its influence on global circulation in order to predict rainfall and variability at various periods of time; and to test, evaluate and to test, evaluate and improve satellite rainfall measurement techniques.

For additional information on the TRMM program, call the Goddard Newsroom at (301) 286-8955. The next TRMM status report will be issued on or about Dec. 15, 1997, though some instrument images may be released as early as this week.

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