Jess (falconry) chase something it shouldn't, and less to keep the bird from getting away, as falconry birds are routinely (and as part of the sport) set free—the bond between bird and falconer serves as a much better leash than any leather or rope ever will; however, it is not always desirable that a bird be able to take flight at its own whim, and both on the glove and on the perch, jesses help ensure this. During hunting season (small game season for North American falconers), jesses are generally worn all season in the mews, and are often removed for the
Momentum exchange tether field such as around the Earth, a conducting tether can be configured as an electrodynamic tether. This can either be used as a dynamo to generate power for the satellite at the cost of slowing its orbital velocity, or it can be used to increase the orbital velocity of the satellite by putting power into the tether from the satellite's power system. Thus the tether can be used to either accelerate or to slow an orbiting spacecraft without using any rocket propellant. When using this techniques with a rotating tether, the current through the tether must alternate in phase with