ICON: Where earth's weather meets space weather

The Ionospheric Connection Explorer (ICON) is a NASA Heliophysics Explorer Mission designed to study the ionosphere, the boundary between Earth and space. This region, where ionized plasma and neutral gas collide and react, exhibits dramatic variability that affects space-based technological systems like GPS. The ionosphere has long been known to respond to space weather drivers from the sun, but recent NASA missions have shown this variability often occurs in concert with weather on our planet. This paper addresses the overall mission design and architecture of ICON, system design trades that have occurred through phase B of development, and challenges unique to the ICON mission. Set to launch in June 2017, ICON will perform a two-year mission to observe conditions in both the thermosphere and ionosphere. ICON's science objectives are to: 1) understand the source of strong ionospheric variability, 2) the transfer of energy and momentum from our atmosphere into space, and 3) how solar wind and magnetospheric effects modify the internally-driven atmosphere-space system. ICON will accomplish these 3 science objectives using a suite of 4 instruments mounted to a composite deck aboard an Orbital Sciences Corporation LEOstar-2 spacecraft bus. Dual Michelson Interferometers for Global High Resolution Thermospheric Imaging (MIGHTI) will measure neutral winds in the thermosphere, and temperatures at the boundary of space. Two Ion Velocity Meters (IVM) will measure in situ ion drifts in the ionosphere. Two ultraviolet spectrographic imagers, a Far Ultraviolet (FUV) and an Extreme Ultraviolet (EUV), will observe the airglow layers in the upper atmosphere in order to determine both the ionospheric and thermospheric density and composition. Finally, the current state of the program will be summarized and the project's plans for the future will be discussed.