Engineers at the U.S. Naval Research Laboratory (NRL) are designing an instrument, MIGHTI, the Michelson Interferometer for Global High-resolution Thermospheric Imaging that will be part of NASA’s Iconospheric Connection Explorer or ICON Explorer- class mission scheduled for launch in the summer of 2017. MIGHTI will measure and analyze the Earth’s upper atmosphere or ionosphere and its findings could lead to improved long-wave radio communications. The instrument is named for Albert Michelson, a Nobel-prize winning physicist known for researching the measurement of light using a similar type of interferometer.
The Earth’s ionosphere is a boundary layer between the planetary atmospheres and space, and is vital to long-distance radio wave propagation. Solar energy and the dynamic forces from lower atmospheric layers create unpredictable behavior that interferes with communications, as well as radar and geo-positioning.
The ICON satellite will measure the state of ionosphere, including the environmental space conditions and how weather on Earth affects those conditions. MIGHTI will aid ICON by measuring the neutral winds and temperatures of the low latitude thermosphere. MIGHTI will determine the winds and temperature using the DASH technique (Doppler Asymmetric Spatial Heterodyne spectroscopy). This means MIGHTI will measure the Doppler shift of atmospheric emissions and then derive the wind velocities and temperatures. ICON will carry two MIGHTI units to make measurements in two views perpendicular to the Earth’s atmosphere. For example, as ICON travels east and takes images of the ionosphere and thermosphere, MIGHTI will measure the vector components of the vertical wind profile.