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 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.
