Earth observations are one of the most essential functions of our current fleet of satellites. Typically, each satellite specializes in one kind of remote sensing—monitoring ocean levels, for example, or watching clouds develop and move. That is primarily due to the constraints of their sensors—particularly the radar. Earth observations are one of the most essential functions of our current fleet of satellites. Typically, each satellite specializes in one kind of remote sensing—monitoring ocean levels, for example, or watching clouds develop and move. That is primarily due to the constraints of their sensors—particularly the radar. Planetary Sciences Phys.org – latest science and technology news stories