eos

Earth observation satellites are satellites specifically designed to observe Earth from orbit, similar to spy satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc.
Most Earth observation satellites carry instruments that should be operated at a relatively low altitude. Altitudes below 500-600 kilometers are in general avoided, though, because of the significant air-drag at such low altitudes making frequent orbit raising manoeuvres necessary. The Earth observation satellites ERS-1, ERS-2 and Envisat of European Space Agency as well as the MetOp spacecraft of the European Organisation for the Exploitation of Meteorological Satellites are all operated at altitudes of about 800 km. The Proba-1, Proba-2 and SMOS spacecraft of European Space Agency are observing the Earth from an altitude of about 700 km.

The Earth Observing System (EOS) is a program of NASA comprising a series of artificial satellite missions and scientific instruments in Earth orbit designed for long-term global observations of the land surface, biosphere, atmosphere, and oceans of the Earth. The satellite component of the program was launched in 1997. The program is centerpiece of NASA's Earth Science Enterprise (ESE).

The Capillary Pumped Loop (CAPL) Flight Experiment will provide a microgravity test of a full sized prototype
for a capillary pumped thermal control system. This two-phase system utilizes an ammonia working fluid to
transfer large amounts of heat over long distances at nearly constant temperature. Capillary pumped systems will
be used for thermal control on Earth Observing System (EOS) satellites and other future missions. CAPL is
sponsored by NASA's Goddard Space Flight Center EOS project and will fly as a Hitchhiker payload on the space
shuttle.