On August 22, NASA completed a set of maneuvers on the Tropical Rainfall Measuring Mission (TRMM) spacecraft to boost its orbit around Earth. The push into a higher orbit will prolong the satellite's life and continue to provide meteorologists and climatologists data to forecast and better understand global climate change.
The satellite was gently nudged to its new orbit altitude under the control of NASA engineers at Goddard Space Flight Center in Maryland. Now after the satellite's successful first three years, and with fuel starting to run low, scientists realized that they could extend the mission's life and gather further vital information by raising TRMM's orbit from 350 kilometers (km) to 402 km away from Earth.
The TRMM satellite has been recording rainfall data over the tropics since it was launched in 1997. TRMM has already achieved or surpassed many of its original goals since it became operational. These include collecting data on rainfall and the heat release associated with rainfall, as well as information about interactions between water vapor, clouds and precipitation that are central to regulating the climate system.
"Raising TRMM's orbit to 402 km could extend the lifespan of TRMM to somewhere between 2005 and 2007," said TRMM Project Scientist, Dr. Robert Adler of NASA Goddard.
By changing the orbit, NASA engineers do not have to burn as much fuel to make orbit adjustments to counter effects of drag and friction at 350 km. More importantly, from a science standpoint, an extended mission provides a more robust climate record of rainfall. It also gives scientists a chance to capture additional information about the global changes in rainfall that occur during El Nino and La Nina events. "The extension of TRMM's life also creates an opportunity to verify data with future missions, like NASA's AQUA (a water cycle mission satellite that includes rainfall measurements) and Japan's ADEOS II (The Advanced Earth Observing Satellite II)," continues Dr. Adler.
"An extended mission would benefit operational weather forecasters, scientists addressing critical questions related to climate change and global warming, and policymakers," said Goddard Research Meteorologist, Dr. J. Marshall Shepherd.
With the pressing need to understand climate change better and faster, a longer record of TRMM data can be combined with data being collected from the current satellites like Terra, and future climate monitoring satellites like AQUA and ADEOS II. The wide variety of data sources will provide more complete parameters to feed into NASA global climate models. This in turn could lead to further improvements in climate prediction. And, a longer TRMM mission also allows scientist to more firmly establish potential links between pollution and rainfall suppression.
Operational centers like the NOAA's National Hurricane Center and the Department of Defense's Joint Typhoon Warning Center can continue to use TRMM data for hurricane identification and monitoring. Additionally, NOAA's National Center for Environmental Prediction and the European Center for Medium Range Weather Forecasting (ECMWF) are just now beginning to test TRMM data in weather forecasts models, such that an extension of TRMM mission life has potential future benefits in weather prediction.
TRMM is a joint mission between NASA and the Japanese Space Agency (NASDA).
For more information on the TRMM mission, visit http://trmm.gsfc.nasa.gov
For more information about AQUA, see: http://eos-pm.gsfc.nasa.gov/
For more information about ADOES-II see:
http://www.nasda.go.jp/Home/Projects/ADEOS-II/index_e.html