The tiny payload, known as IceCube or Earth-1, will demonstrate and validate a new 874-gigahertz submillimeter-wave receiver that could help advance scientists' understanding of ice clouds and their role in climate change. IceCube will fly on a three-unit or 3U CubeSat, which is comprised of individual units each about four inches on a side and weigh about three pounds. IceCube will lead to the development of an instrument capable of providing an accurate daily assessment of the global distribution of atmospheric ice.