Tether applications in space transportation

The high cost of delivering rocket propellants to orbit for use there makes attractive the use of alternative reaction masses such as other spacecraft, planetary magnetospheres and atmospheres, light, and celestial bodies. Some of these alternatives have already been used in special cases, but tethers may be the key to using all of them on a far more general and ambitious basis. This paper gives a general overview of the many ways tethers might be used in space transportation. There is an emphasis on near-term applications such as payload boosting and space station momentum management.