Source: NOVA scienceNOW: "Franklin Chang-Díaz"
In this video segment adapted from NOVA scienceNOW, meet Franklin Chang-Díaz, an astronaut and scientist. Learn how he has been interested in rockets and space travel since he was a child in Costa Rica, and how he immigrated to the United States to pursue his dream of becoming an astronaut. Hear how he found success in school and eventually was chosen as NASA's first Latin American astronaut. In addition, find out about a new type of rocket that he is developing, which uses a plasma engine, and may help one day facilitate human colonization of the solar system.
Since childhood, Franklin Chang-Díaz has been interested in space exploration. He achieved his dream to travel in space by becoming NASA's first Latin American astronaut and has since flown in space seven times. He continues to pursue his other dream, which he has also had since childhood: to improve methods of space travel. He is now making progress toward the development of a new type of rocket technology—the Variable Specific Impulse Magnetoplasma Rocket (VASIMR)—that would use plasma to revolutionize space travel.
Rockets are propelled by the expulsion of material in the opposite direction from the desired flight trajectory. Conventional rockets use a chemical reaction (the combustion of fuel) to produce exhaust that is expelled out the back of the rocket, pushing the rocket forward. The VASIMR system would use plasma—a state of matter that is created when a gas is heated to such high temperature that its electrons break free from its atoms. Very high velocity exhaust material can be produced by the extremely high heat of the plasma, which means that less propellant is needed to create an adequate amount of thrust. In conventional rockets, the fuel accounts for most of the mass of the system (which doesn't allow for the rocket to carry much else), and it is not very efficient; a conventional rocket would take about seven months to reach Mars. In contrast, a plasma-powered rocket could carry bigger payloads and would be able to travel to Mars in just 40 days!
The VASIMR has three basic steps. First, low frequency electromagnetic waves and a magnetic field work together to heat a neutral gas, such as argon, until it becomes plasma. Next, electromagnetic waves further energize the plasma to higher temperature. Finally, magnetic fields act as a "magnetic nozzle" to direct the motion of the plasma, converting its energy into thrust to propel the rocket.
Franklin Chang-Díaz first envisioned this new type of rocket while he was a graduate student studying applied plasma physics. He dreamed of a future where space travel was fast and efficient enough that humans could populate the solar system. With a plasma-powered rocket, interplanetary travel times would be short enough that it could even be possible to explore the entire solar system and create colonies on the Moon. Although the technology has not yet been developed to achieve this dream in the near future—for example, no one has yet developed a nuclear reactor for use in space, a prerequisite technology needed to generate the electrical power for the engine—Franklin Chang-Díaz is making progress. The first step toward this new future of space travel will be to create a less powerful version of the engine that could be powered by solar electricity for use near Earth and the Moon.
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