Resumen de Electrodynamic tethers in space.

Enrico Lorenzini, Juan Sanmartín

• The article looks at electrodynamic tether systems, which could perform many of the same functions as conventional spacecraft but without the use of chemical or nuclear fuel sources. Every spacecraft on every mission has to carry all the energy sources required to get its job done, typically in the form of chemical propellants, photovoltaic arrays or nuclear reactors. So scientists are taking a look at an experimentally tested technology--the space tether--that exploits some fundamental laws of physics to provide pointing, artificial gravity, electrical power, and thrust or drag, while reducing or eliminating the need for chemical-energy sources. Many scientists believe that the technology could revolutionize some types of spaceflight. Tethers exploit the sometimes counterintuitive quirks of orbital mechanics. Switching on a propulsive electrodynamic tether at the right time along the orbit can produce lateral forces useful for changing the inclination of any spacecraft in orbit--an operation that requires a large amount of fuel when it is carried out with chemical thrusters. Designers will have to devise ways to protect tethers from the effects of the high electrical potential between the tether and the ionosphere as well as from the slow degradation of materials in space. And they must learn to control the various vibrations that arise in electrodynamic tether systems. INSETS: HOW ELECTRODYNAMIC TETHERS WORK;USING TETHERS TO REMOVE OBJECTS FROM ORBIT;ARTIFICIAL GRAVITY FROM A TETHER;TETHERED MISSIONS