Electrical charging of space platforms at low earth orbit altitudes

We will adopt the definition that low-earth-orbit (LEO) altitudes span the range 270 - 1000 km above the surface of the Earth. In this altitude region, free charges exist in the form of the ionospheric plasma. At its lower boundary the plasma density is much lower than the neutral gas density, while at its upper boundary the plasma density exceeds the neutral density. The presence of the charged particles results in objects immersed in this region acquiring a net electrical charge either naturally, or as a result of active systems that modify the charged particle fluxes to the surfaces of these objects. (C) 1999 COSPAR. Published by Elsevier Science Ltd.