NASA ends pioneering pollution sensor

The U.S. National Aeronautics and Space Administration (NASA) ended the Tropospheric Emission Spectrometer's (TES) almost 14-year career of discovery on Jan. 31, the U.S. space agency said on Tuesday.

Launched in 2004 on NASA's Aura spacecraft, TES was the first instrument designed to monitor ozone in the lowest layers of the atmosphere directly from space.

The instrument was planned for a five-year mission but far outlasted that term. It was originally conceived to measure ozone in the troposphere. However, TES cast a wider net, capturing signatures of a broad array of other atmospheric gases as well as ozone.

That flexibility allowed the instrument to contribute to a wide range of studies, not only atmospheric chemistry and the impacts of climate change, but studies of the cycles of water, nitrogen and carbon.

Its high-resolution observations led to new measurements of atmospheric gases that have altered our understanding of the Earth system, said NASA.

"TES was a pioneer, collecting a whole new set of measurements with new techniques, which are now being used by a new generation of instruments," Kevin Bowman, the TES principal investigator of NASA's Jet Propulsion Laboratory (JPL) was quoted as saying in a news release.

A mechanical arm on TES began stalling intermittently in 2010, affecting the instrument's ability to collect data continuously. The TES operations team adapted by operating the instrument to maximize science operations over time, attempting to extend the data set as long as possible, according to NASA.

However, the stalling increased to the point that TES lost operations about half of last year. The data gaps hampered the use of TES data for research, leading to NASA's decision to decommission the instrument.

It will remain on the Aura satellite, receiving enough power to keep it from getting so cold that it might break and affect the two remaining functioning instruments.

New techniques developed for TES along with broad applications throughout the Earth System ensure that the mission's legacy will continue long after TES's final farewell, said NASA.