SAGE III on ISS

SAGE III on ISS is the fourth generation of a series of NASA Earth-observing instruments, known as the Stratospheric Aerosol and Gas Experiment.

The recently revised SAGE III was mounted to the International Space Station where it uses the unique vantage point of ISS to make long-term measurements of ozone, aerosols, water vapor, and other gases in Earth's atmosphere.

Recently, the opportunity arose for SAGE III to be placed on ISS, and build on the long record of stratospheric gas data that its ancestors created.

The week of 14 February 2011, scientists at NASA Langley Research Center pulled the instrument from storage to begin initial testing and calibrations in preparation prepping it for launch.

The SAGE III mission is an important part of NASA's Earth Observation System and is designed to fulfill the primary scientific objective of obtaining high quality, global measurements of key components of atmospheric composition and their long-term variability.

Clouds play a major role in determining the planet's solar and longwave energy balance and, thus, are important in governing the Earth's climate.

Also, the presence of thin cloud near the tropopause may play a significant role in heterogeneous chemical processes that lead to ozone destruction in mid-latitudes.

It is important to monitor ozone levels in the lower stratosphere and upper troposphere since observed trends are the largest and most poorly understood at those altitudes.

In particular, the long-term stability and self-calibration capabilities of SAGE III may permit the detection of trends in stratospheric and mesospheric temperature that will be important diagnostics of climate change.

SAGE III nitrogen dioxide measurements are important because the processes that occur in the Antarctic winter and spring and give rise to the ozone hole effectively convert NO2 to nitric acid (HNO3).

Since it is measured during both solar and lunar occultation events, SAGE III observations of NO2 will improve our understanding of the strong diurnal (daily) cycles in stratospheric processes.

SAGE III on ISS mission logo
SAGE III on ISS preparing for its scan of the Moon on 17 February 2011. The SAGE team arrived at midnight to continue testing the instrument, which will be attached to the space station to measure ozone, water vapor and aerosols in the Earth's atmosphere.
SAGE III instrument
From 21 to 30 September 2006, the average area of the ozone hole was the largest ever observed, at 10.6 million square miles (27.5 million square kilometres). This image, from 24 September 2006, the Antarctic ozone hole was equal to the record single-day largest area of 11.4 million square miles (29.5 million square kilometres), reached on 9 September 2000. The blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where there is more ozone.
Artist rendering of SpaceX Cargo Dragon spacecraft delivering cargo to the International Space Station