NASA's Ionospheric Connection Explorer, or ICON, launches in December 2017 and orbits above the upper atmosphere, through the bottom edge of near-Earth space. From this vantage point, ICON observes both the upper atmosphere and a layer of charged particles called the ionosphere, which extends from about 50 to 360 miles above the surface of Earth. Processes in the ionosphere also create bright swaths of color in the sky, known as airglow. ICON will observe how interactions between Earth's weather and the ionosphere create such shimmering airglow as well as other changes in the space environment.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 22.214.171.124.0