NASA Orbiter is a term used to refer to spacecrafts that are designed to orbit around the Earth or other celestial bodies. The two most well-known NASA Orbiters are the EOS (Earth Observing System) and the ISS (International Space Station). The EOS is a series of satellites that are used to observe and monitor the Earth's environment and climate. The ISS is a space station that has been continuously inhabited since 2000 and is used for research and exploration.