Plasma rocket breaks endurance record
Reuters and http://NewScientist.com
A revolutionary plasma rocket engine has been tested for a record time of more than four hours at a test facility in Costa Rica. Scientists at the Ad Astra Rocket Company hope the engine will eventually be cheaper to operate than conventional models and will reduce travel time for space missions.
The company, led by Costa Rican-born, former NASA astronaut Franklin Chang-Diaz, hopes to use its rocket engines to boost commercial spacecraft into higher orbits, stabilise space stations, and then to power a trip to Mars within two decades, cutting the travel time by about a third to around three months.
The engine works by stripping electrons from hydrogen atoms and accelerating the resulting plasma in an electric field. Expelling the plasma out of the back of the engine generates thrust. The technique is known as Variable Specific-Impulse Magnetoplasma Rocket (VISIMR) technology, and was conceived in the 1970s.
Artificial gravity
Unlike conventional rockets which generate all their thrust in the first few minutes of a mission and then coast to their destination, a VISIMR engine accelerates continuously.
This reduces journey times, and could also provide a low level of artificial gravity for astronauts. It has been suggested that the hydrogen fuel, which is common throughout the universe, could be harvested en route.
There are significant challenges ahead, however. "The first objective is to move small spacecraft in low orbit by 2010," said Ad Astra executive director Ronald Chang-Diaz, the astronaut's brother.
In December, the team ran the engine for two minutes, but had to turn it off because of overheating. They have spent much of the past six months designing cooling systems.
Scientists at Ad Astra's Houston laboratory are conducting tests aimed at boosting the engine's overall power, while in Costa Rica they focus on endurance, Ronald Chang-Diaz said