The Stratospheric Aerosol and Gas Experiment (SAGE) III instrument animations

The Stratospheric Aerosol and Gas Experiment (SAGE) III instrument is used to measure aerosols, tiny particles in the atmosphere, and gases such as ozone which acts as Earth’s sunscreen. SAGE III is the newest and most advanced addition to the SAGE family of instruments. It was robotically installed on the outside of the ISS and is now taking important measurements of stratospheric gases and aerosols over 70% of the planet.



More than 25 years ago, scientists realized there was a problem with Earth’s thin, protective coat of ozone. The SAGE family of instruments was pivotal in making accurate measurements of the amount of ozone loss in Earth’s atmosphere. SAGE has also played a key role in measuring the onset of ozone recovery resulting from the internationally mandated policy changes that regulated chlorine-containing chemicals, the Montreal Protocol, which was passed in 1987.



In the coming decades, ozone recovery and climate variability will be key topics to study. NASA and SAGE will continue to help scientists understand Earth’s changing climate, allowing us to better protect our planet.