More on the NASA, Scientist, Astronaut.
Franklin Ramón Chang-Díaz (born April 5, 1950) is a Costa Rican-American engineer, physicist and former NASA astronaut. He is a veteran of seven Space Shuttle missions, making him the record holder for most spaceflights (a record he shares with Jerry L. Ross). He was one of the first Hispanic or Latino Americans to go into space
Chang-Diaz was born in San José, Costa Rica to a father of Chinese descent and a Spanish Costa Rican mother, both Costa Rican-born<3>. He studied at La Salle School, then moved to the United States to finish his high school education. He earned a B.S. degree in mechanical engineering from the University of Connecticut (where he joined the federal TRIO Student Support Services program) in 1973, and a Sc.D. degree in applied plasma physics from the Massachusetts Institute of Technology (MIT) in 1977. For his graduate research at MIT, Chang-Diaz worked in the field of fusion technology and plasma-based rocket propulsion.
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http://en.wikipedia.org/wiki/Franklin_Chang-DiazMore on the rocket technology : The Variable Specific Impulse Magnetoplasma Rocket, sometimes referred to as Electro-thermal Plasma Thruster, uses radio waves to ionize and to heat propellant and magnetic fields to accelerate the resulting plasma to generate thrust. This type of engine can be viewed as a variation (differing in the method of plasma acceleration) of the electrodeless plasma thruster. Neither type of engine has any electrodes. The main advantage of such designs is elimination of problems with electrode erosion. Furthermore, since every part of a VASIMR engine is magnetically shielded and does not come into direct contact with ionized plasma, the potential durability of this engine design is greater than other ion engine designs.
The engine design encompasses three parts: turning gas into plasma via helicon RF antennas; energizing plasma via further RF heating in an ICRF booster; and using electromagnets to create a magnetic nozzle to convert the plasma's built-up thermal energy into kinetic force. By varying the amount of energy dedicated to RF heating and the amount of propellant delivered for plasma generation VASIMR is capable of either generating low-thrust, high-specific impulse exhaust or relatively high-thrust & low-specific impulse exhaust
he Variable Specific Impulse Magnetoplasma Rocket, sometimes referred to as Electro-thermal Plasma Thruster, uses radio waves to ionize and to heat propellant and magnetic fields to accelerate the resulting plasma to generate thrust. This type of engine can be viewed as a variation (differing in the method of plasma acceleration) of the electrodeless plasma thruster. Neither type of engine has any electrodes. The main advantage of such designs is elimination of problems with electrode erosion. Furthermore, since every part of a VASIMR engine is magnetically shielded and does not come into direct contact with ionized plasma, the potential durability of this engine design is greater than other ion engine designs.
Wiki:
http://en.wikipedia.org/wiki/VASIMR