ION SOURCES FOR SPACE THRUSTERS

One of the main tasks of the creation of spacecraft power plants is ra ising the thrust producing jet velocity. Conventional chemical engines create jet velocities in the range of 3000-4500 m/s. This situation c an be drastically changed if beams of charged particles accelerated by electric and magnetic fields are used to produce thrust. In such case s practically any jet velocity might be created, which considerably en larges the number of tasks being fulfilled by spacecraft having such t ypes of thruster. Several types of electric propulsion thrusters exist nowadays. They differ in the principles of acceleration of charged pa rticles, for example, are jets, magnetic plasma dynamic thrusters, sta tionary plasma thrusters, pulse thrusters, and ion thrusters. Electric propulsion thrusters are practically the accelerators of charged part icles which operate under rather strict requirements concerning energy consumption and lifetime. Since the mid-fifties in Russia there have been intensive studies of practically all types of electric propulsion thrusters, including their tests in space, and beginning with the mid -seventies they have been practically used aboard spacecraft with a lo ng, active lifetime. The study of the physical process involved togeth er with the research design allowed Russian scientists to develop elec tric propulsion thrusters in the power range from hundreds of watts to tens of kilowatts, with jet velocities between 20000 and 50000 m/s an d lifetime more than several thousand hours. (C) 1996 American Institu te of Physics.