Franklin R. Chang-Díaz: 1950—: Astronaut, Physicist

Chang-Díaz's research on plasma rocket engines could lead to technology that would significantly reduce the amount of time required to travel from Earth to Mars. With current technology, based on chemical propulsion, rockets can achieve a speed of only 10,000 miles per hour; this would make a trip to Mars take at least ten months each way. Higher rocket speeds could be reached if the spacecraft's propellant were super-heated—but this, Chang-Díaz has pointed out, would cause the rocket to melt. But the variable specific impulse magnetic resonance (VASIMR) propulsion system, on which Chang-Díaz has worked for more than 20 years, avoids this problem by using magnetic fields to contain and guide the propellant gases. Chang-Díaz described the process, in a New York Times article, as "like a microwave oven."

With the VASIMR engine, rockets could achieve speeds of 650,000 miles per hour. At the same time, Chang-Díaz explained, VASIMR's superior fuel efficiency would significantly reduce the weight of the space-craft—and therefore the high cost of space missions. He has calculated that a VASIMR—powered mission to Mars, including one spacecraft for astronauts and another for supplies, would weigh only about 400 tons half the weight of an earlier design for a Mars mission. VASIMR technology could cut the time of a mission from Earth to Mars from ten months to only 93 days. Though VASIMR is not the only propulsion system being considered by NASA, Chang-Díaz said in the New York Times that "I think it's the technology that's going to take us to Mars." The VASIMR propulsion system could be operational for a Mars mission by 2018.

Active in promoting support for space programs, especially in Latin America, Chang-Díaz has also participated in community service work. He spent two and a half years as a house manager in an experimental residence for chronic mental patients who were being released from institutionalized care. He has also worked as an instructor and advisor for a Massachusetts rehabilitation program for Hispanic drug abusers. Chang-Díaz travels widely in the United States, Mexico, and Latin America, speaking on the importance of sharing space-age technologies with developing nations.