Launched in July 2004 on NASA's Aura spacecraft, the Tropospheric Emission Spectrometer (TES) instrument was an infrared sensor designed to measure chemical components of Earth's troposphere. TES is one of four science instruments aboard NASA's Aura satellite, the third of NASA's Earth Observing System (EOS) spacecraft. which was launched from Vandenberg Air Force Base, California into sun-synchronous orbit. TES operated from July 2004 to January 2018 and helped assess the challenges of global climate change and air pollution and improve our understanding of the atmosphere's chemistry. TES provided high-resolution measurements of ozone, water vapor, carbon monoxide, methane, nitrous oxide, and nitric acid for 16 orbits every other day. In 2010, scientists devised a way to use TES data to also assess global carbon dioxide levels.
Mission Objectives
The primary objective of TES is to make global, three-dimensional measurements of ozone and other chemical species involved in its formation and destruction.
Orbital Characteristics
The satellite flies at an altitude of 705 km (438 miles) in an orbit that takes it near Earth's North and South Poles. With each orbit, the spacecraft advances 22° westward. After 233 orbits (16 days), it is back at its starting point and the pattern repeats. Thus, every 16 days, Aura re-examines the same portions of the atmosphere, and its instruments are able to measure changes that may have occurred in each sampled area.
Mission Conclusion
On Jan. 31, 2018, NASA ended the Tropospheric Emission Spectrometer's almost-14-year career of discovery. At 11:00am PST during a scheduled real time satellite contact, the TES IOT along with the Aura FOT commanded the TES instrument to its decommissioned state. The transition occurred as planned, there were no complications. A full NASA press release for the TES instrument can be found here "Farewell to a Pioneering Pollution Sensor".
The scientific discovery mission of Tropospheric Emission Spectrometer has concluded. However, a final full TES dataset (v008) was generated from an algorithm update to the base Ground Data System software and will be made available to the scientific community in the next two years.
The satellite and its instruments were originally scheduled to perform their atmospheric studies for five years but operated successfully for nearly 14 years.