November 4, 2008
Magnetic Shield Could Allow For Manned Mars Mission
The development of a magnetic shield could have great implications for the future of space travel.
Space weather is the single greatest obstacle to deep space travel, according to international space agencies. Radiation from the sun and cosmic rays pose a deadly threat to astronauts in space.Scientists announced on Tuesday that a spaceship equipped with a magnetic field generator could reduce the threat to acceptable levels.
The magnetic field generator mimics the protective field that envelops the Earth, known as the magnetosphere. The discovery could pave the way for man's first mission to Mars, scientists said.
Lab tests are reported in the journal Plasma Physics and Controlled Fusion.
Large numbers of these energetic particles occur intermittently as "storms" with little warning and are already known to pose the greatest threat to man. Nature helps protect the Earth by having a giant "magnetic bubble" around the planet called the magnetosphere.
International space agencies acknowledge that astronauts face a significant risk of ill health and even death if they experience major exposure to this harsh environment.
And even the spacecraft themselves are not immune to the effects. A solar flare crippled the electronics on Japan's mission to Mars, Nozomi, in 2002, for example.
Now researchers from the Rutherford Appleton Laboratory, the Universities of York and Strathclyde, and IST Lisbon hope to develop and equip spaceships with miniature magnetosphere.
The idea has been around since the 1960's but it was thought impractical because it was believed that only a very large (more than 100km wide) magnetic bubble could possibly work.
Using previous knowledge gained from 50 years of research into nuclear fusion, scientists have shown that it is possible for astronauts to shield their spacecrafts with a portable magnetosphere - scattering the highly charged, ionized particles of the solar wind and flares away from their spacecraft.
Computer simulations done by a team in Lisbon with scientists at Rutherford Appleton last year showed that theoretically a very much smaller "magnetic bubble" of only several hundred meters across would be enough to protect a spacecraft.
It was not initially clear the idea would work, said Ruth Bamford, who led the research.
"There was a belief that you couldn't make a little hole in the solar wind small enough to do this at all," said Bamford.
"It was believed that you had to have something very large, approaching planetary scale, to work in this way."
To create its meter-sized trial, the team used a plasma jet and a simple $20 magnet.
"The first time we switched it on, it worked," Bamford said.
What is more, the trial field seems to adjust itself automatically. "It does have the capacity to be somewhat self-regulating, just like the Earth's magnetosphere is," she added.
"When it gets a strong push from the solar wind, the bubble gets smaller. The video shows us increasing the pressure of the solar wind, and the shield gets smaller but brighter."
Many more experiments are needed, Bamford admits, to understand how best to harness the effect; and a practical implementation is probably 15 to 20 years away.
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