VATIS UPDATE Article

A NASA instrument to monitor aerosols, the ozone layer, and other gases in our atmosphere from space arrived on November 2015 at NASA’s Kennedy Space Center in Florida, USA. The instrument began final preparations for launch to the International Space Station. The Stratospheric Aerosol and Gas Experiment III on the International Space Station, or SAGE III on ISS, was shipped to Florida from NASA’s Langley Research Center in Hampton, Virginia, USA.

The SAGE III instrument, devel­oped at NASA Langley, went through final tests before being stowed aboard a SpaceX Falcon 9 rocket as part of a NASA space station SpaceX resupply mission. The SAGE III instrument will be used primarily to study ozone, a gas found in the upper atmosphere that acts as Earth’s sunscreen by blocking much of the Sun’s harmful ultraviolet radiation. More than 30 years ago, scientists discovered that our planet’s protective coat of ozone was thinning. Since then, NASA has orbited a series of increasingly sophisticated SAGE instruments to make accurate measurements of ozone amounts in the upper atmosphere.

The SAGE III instrument measures light intensities observed at the space station after passing through the Earth’s atmosphere during sunsets, sunrises, moonsets and moonrises. As the ISS goes behind the Earth relative to the sun or moon, the instrument measures the dimming of the sunlight or moonlight caused by the Earth’s atmosphere. This dimming, in turn, changes with changing atmospheric aerosol and ozone levels. By making these measurements, SAGE III will provide a long-term data record of key components of the Earth’s atmosphere vital for improved understanding of climate change and ozone chemistry.