Experimental Investigation of Spacecraft Glow (EISG)/ Spacecraft Kinetic Infrared Test (SKIRT) consists of two
complementary experiment assemblies. Both are designed to measure spacecraft glow, which occurs when the rapidly
moving orbiter rams into atoms of oxygen and molecules of nitrogen in low Earth orbit, causing them to give off light. When
the orbiter passes in and out of darkness and light as ft circles the Earth, its surface temperature changes, thus affecting the
illumination range of the atomic particles. The EISG and SKIRT sensors will measure spacecraft glow as a function of
temperature.