MISSION TO MARS? A practical shield from energetic particles must be devised first.
Image: NASA/JPL
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If astronauts hope to ever set foot on Mars, myriad technical challenges will need to be overcome, not the least of which is shielding space travelers from bombardment by energetic particles. Outside Earth's protective atmosphere and magnetic field, supersonic particles from stellar processes run amok, screaming through space and tearing through just about anything in their path—including the bodies of astronauts, where they can wreak havoc on genetic material.
Over the years, a number of protective schemes has been proposed from physical barriers to magnetic or electrostatic shields—solutions that some prominent critics have deemed hopelessly impractical. But a group of European researchers has nonetheless taken to testing a magnetic force field approach in the laboratory, yielding results that they say show "the potential viability" of the technology.
Ruth Bamford, a physicist at Rutherford Appleton Laboratory in Didcot, England, and her colleagues fired a plasma beam of charged particles traveling above Mach 3, a stand-in for a stream of energetic solar particles, at an induced magnetic field. What they observed was an almost total deflection of charged particles around the field—a "mini magnetosphere" of relative safety, according to their study published online today by the journal Plasma Physics and Controlled Fusion.
While this strategy has long been on the table as a potential solution to the radiation problem, past approaches have deemed it untenable. As noted by Eugene N. Parker, a professor emeritus of physics at the University of Chicago, in a 2006 Scientific American article, the weight of such a system would be too great for practical space travel. Parker wrote that Nobel laureate "Samuel C. C. Ting of the Massachusetts Institute of Technology headed up a design group that devised such a system with a mass of only nine tons ... still discouragingly heavy to think of carrying all the way to the Martian surface and back."
The system Parker describes is predicated on the need to create a mammoth magnetic field of 20 teslas—some 600,000 times what one would find at the Earth's equator. Bamford is quick to caution that her team's results are preliminary, but she believes that an effective field could be much weaker, perhaps just one tesla.
The large-magnet approach, Bamford says, "is based on the assumption that you need to create a very large bubble," multiple kilometers across. "What we've been working on is the assumption that the bubble doesn't have to be that large—as small as 100 meters across," she says, "and you can get away with a much smaller magnet." This discrepancy owes in part to the fact that Bamford's team focused on solar energetic particles (those emitted from our sun) while Parker focused on cosmic-ray particles from exploding stars elsewhere in the universe.
"I was more concerned about the galactic cosmic rays, which are higher-energy, which takes therefore a stronger magnetic field," Parker says. His estimates hinge on the need to deflect particles some 20 times more energetic than those targeted by Bamford and her colleagues. The risks of those particles are not insignificant: cosmic rays would do enough damage over a year's journey through the solar system to break through a third of the DNA in an astronaut's body, according to a NASA estimate cited by Parker. (A round-trip to Mars, with current technology, would take at least that long.)
"There is still the unknown medical end of things that has not been properly investigated," Parker says, referring to the unknown effects of such long-term exposure to radiation. "And it is not obvious how to investigate it properly."
Bamford acknowledges that the magnetic field approach is not a magic bullet—more like an arrow in the quiver. Other strategies, she says, would have to be developed to minimize the risk to astronauts. But if a lightweight deflector of solar energetic particles could be developed, a trip to Mars might appear just that much less far-fetched.
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7 Comments
Add CommentIs Mars not magnetic? Sounds to me like we really just have to heat it up and get it to support it's own atmosphere first. Seed the planet with bacteria that would produce an atmosphere... while having astronauts living underground in mines and factories that would pollute the heck out of the planet in order to warm it up and give it a sustainable atmosphere. A thick atmosphere in combination with Mars' own magnetic field should be sufficient.
Reply | Report Abuse | Link to thisIn the mean time, living underground would shield the Martians well enough from cosmic radiation to protect their DNA. The radiation should help the terraforming seed bacteria to mutate quickly enough to adapt to the Martian environment.
Mars has its own magnetic field, but it is very small and insignificant. You'd get more protection from a football helmet than the entire planet's magnetic sphere. That lack of protection is the reason why Mars has no significant atmosphere. Solar winds have blasted away most of the gases of Mars.
Reply | Report Abuse | Link to thisthe best solution for the traveling part would be a combination of the magnetic shield for solar winds, more protective materials for the shuttle's skin to ward off most cosmic rays, and quicker travel to reduce overall exposer time to whatever makes it through. We could assemble the heavier parts at the international space sation to avoid having to lift a two ton shuttle in one take off.
My gut feeling is the vast energies of the cosmic origin, shaped the system we see over millions and millions of human years. It looks ridiculous for a small tiny speck, our planet earth, and its inhabitants to attempt to redefine the force fields with little understanding. But it is exciting to keep on wondering at the discoveries we daily make in our little world with limited reach allowed to us by our extremely constricted tools of senses aided by imagination and conditioned intelligence! That is why we keep on contradicting our once highly laudable scientific truths and dust off again as time progresses, and go back to them! Best is to enjoy the process as long as it lasts! The simple gravity force we have all round us, we don't know much. But I discovered that with stops at 450m, peak speed of 108 kmph, and average speed of 54 kmph, we can have urban transportation on our planet, which can be powered by gravity alone up to 98.65%, if it is rail based transportation! But this means described in a US patent application (12184151 lying with editors of Sciam), which merely needs simple variable gear systems and steel cable with microprocessor based control systems, following only the Newton's classic mechanics, does not excite our editors of journals nor the esoteric particle physics researchers, being unglamorous in scientific terms.But USA can avoid import of 10m barrels of oil daily, by adopting the Gravity Power Towers! This has much more serious practical application to stop global warming and making our life much better qualitatively at much lower prices than the endless search with huge funds invested into other forms of energy. The pre-generated, pre-distributed gravity as source of energy readily available to humans as a gift from our own mother earth, does not need federal research grants--- we can use now! That is the problem or challenge is a matter of our introspection. The real challenge or problem is actually our own mental inertia incapable of belief that actually seemingly complex problems can have simple solutions.
Reply | Report Abuse | Link to thisPLEASE REPLY ME THE FOLLOWING AT THE EARLIEST POSSIBLE :-
Reply | Report Abuse | Link to thisWHAT WILL BE THE EFFECT ON HEALTH, IF A PERSON CONTINUOUSLY STAY IN A STRONG MAGNETIC FIELD FOR ABOUT 8 HOURS ?
EMAIL TO : bablu8936@yahoo.com OR bablu8936@rediffmail.com
PLEASE REPLY ME THE FOLLOWING AT THE EARLIEST POSSIBLE :-
Reply | Report Abuse | Link to thisWHAT WILL BE THE EFFECT ON HEALTH, IF A PERSON CONTINUOUSLY STAY IN A STRONG MAGNETIC FIELD FOR ABOUT 8 HOURS ?
EMAIL TO : bablu8936@yahoo.com OR bablu8936@rediffmail.com
PLEASE REPLY ME THE FOLLOWING AT THE EARLIEST POSSIBLE :-
Reply | Report Abuse | Link to thisWHAT WILL BE THE EFFECT ON HEALTH, IF A PERSON CONTINUOUSLY STAY IN A STRONG MAGNETIC FIELD FOR ABOUT 8HRS. EVERYDAY ?
EMAIL TO : bablu8936@yahoo.com
The japanese love to analyze things to death. Surely, they have studied the effects on passengers on their maglev train. I think they are the ones with the maglev prototypes.
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