Going green

Natural History, Oct, 2005 by Gregory L. Matloff

In his excellent article on the future of space travel, ["Heading Out" (7-8/05)], Neil deGrasse Tyson described some, but not all, of the new "green" space-propulsion technologies. One further possibility is the electrodynamic tether (ET), a thin cable that generates a current when it is pulled through a magnetic field. The tether would work best for objects in low orbit around a planet, such as Jupiter.

Another "green" concept in space propulsion is "aerocapture." A probe approaching an atmosphere-bearing planet could slow down by deploying an appropriate shield or inflatable "ballute" (a combination balloon and parachute). The probe would then make a grazing pass through a planet's atmosphere until it was gravitationally captured as an artificial satellite--a maneuver that can be done without using propellant.

Gregory L. Matloff

New York City College of Technology, CUNY

Brooklyn, New York