Protecting astronauts from the Van Allen radiations

Protecting astronauts from the Van Allen radiations

Summary: An international team of scientists has explained the activity of the two Van Allen radiation belts and this will help protect astronauts and spacecrafts.

TOPICS: Nasa / Space

The Van Allen radiation belts are two regions of space located about 20,000 kilometers above the Earth and filled with energetic particles coming from solar winds. The high energies of these particles, trapped by Earth's magnetic field, can reach millions of electron volts, and can represent a hazard to satellites and humans in space. Now, an international team of scientists has explained the activity of the two Van Allen radiation belts and this will help protect astronauts and spacecrafts. By studying the solar storms of 2003 which disrupted GPS and communications satellites, they found that the old theory, which stated that the electrons within the belts were accelerated by radial diffusion, was wrong. Instead, they discovered that very low frequency radio waves caused the particle acceleration and intensified the belts. With this new information, it will be possible to take measures to protect astronauts, according to the researchers.

"For a long time scientists have been trying to explain why the number of charged particles inside the belts vary so much. Our major breakthrough came when we observed two rare space storms that occurred almost back-to-back in October and November 2003. During the storms part of the Van Allen radiation belt was drained of electrons and then reformed much closer to the Earth in a region usually thought to be relatively safe for satellites," said Dr Richard Horne of the British Antarctic Survey (BAS)

You can see below the evolution of the waves of electrons on October 31, 2003, as observed by one of the four Cluster spacecraft (Samba) (Credit: British Antarctic Survey).

Solar storms from October 2003

The wave electric field Ey, transverse to the ambient magnetic field is shown in (a), and the wave magnetic field By in (b). The colour bars on the right give the calibrated wave powerspectral density for the wave electric field (a), and relative wave power spectral density (in dB) for the wave magnetic field (b).

And here are more details given by Dr Richard Horne.

When the radiation belts reformed they did not increase according to a long-held theory of particle acceleration. Instead, by using scientific instruments in Antarctica and on the CLUSTER mission satellites, we showed that very low frequency radio waves caused the particle acceleration and intensified the belts.
This new information will help spacecraft operators and space weather forecasters who must predict when satellites and missions are most at risk from radiation events allowing them to take measures to protect instruments and systems from damage, and astronauts from risks to their health.

This research work has been published by Nature in its September 8, 2005 issue under the name "Wave acceleration of electrons in the Van Allen radiation belts" (Volume 437, Number 7056, Pages 227-230). Here are two links to the editor's summary and to the first paragraph of the paper.

As a final note, I understand that these scientists have found the mechanism behind these big waves of energy. But I don't really see why it will help to protect astronauts and spacecrafts. Any clues?

Sources: British Antarctic Survey news release, via EurekAlert!, September 7, 2005; and various web sites

You'll find related stories by following the links below.

Topic: Nasa / Space

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  • What I want to know is...

    ...will hanging around in the Van Allen radiation belt give me Fantastic Four-style super powers?
    John Carroll
    • Flame On!

      Oh, wait. Darn near everybody that posts in the ZDNet forums has [b]that[/b] power.

      Stretchiness? Evoryone has the ability to stretch a point beyond all plausibility.

      Hardened skin? Everyone can ignore facts and counterarguments with total impunity.

      Invisibility? When an argument has completely collapsed, everyone can disappear by not continuing to post.

      With all these powers, who need to go into space?
    • No.

      But as the radiation breaks down your DNA and your cells begin to turn into so much organic pudding you will develop the super power to melt. Not sure if that appeals to you much, though.

      Unfortunately the idea of radiation supercharging living organisms as if they were some sort of battery has gone the way of the 1950s. Back when fortifying your water with Radon was considered healthy.

      Following link is worth a laugh[cry].
  • Ok so how did they get to the moon?

    Since the average distance to the moon is 384,402 km, that from the center of the earth to the moon. Now the earth is 12,756.3 KM in diameter so the radius is 6378 KM which you subtract from the distance to the moon to get the distance one would have to travel.

    So if the Van Allens belt is 20,000 KM and to get to the moon you have to trave 378,000 KM then you'd have to pass through it twice. This would effectively kill, not quickly but you might get lucky and live a year afterwards.

    So how did they land on the moon? I dumb luck? I mean were they just plain lucky and the belt just was pumping out radiation all over the place that day?
    • How to get to the moon


      As far as how this new information could be helpful, they may be able to use some sort of interference pattern of low frequency radio waves on board the spacecraft to counteract the effect of the radiation belt, but im just speculating.
    • They didn't spend much time there

      The astronauts going to the moon didn't spend enough time in the Van Allen Belts to accumulate a large dose of radioactivity. They were travelling very quickly when passing through them and any orbital maneuvers were timed for minimal exposure.

      It will however, be a problem for a space elevator, when one is built because they would travel much more slowly. This is probably one of the biggest remaining issues surrounding the feasibility of a space elevator
      • Space Elevator - power generation

        Actually the radiation can be blocked. But the magnetic lines fo force should generate impressive eddy currents in the cables. A conductor passing through a magnetic filed or stationary with a moving magnetic field is a generator.
  • Belt Radiation

    Protection in this case is about avoiding or limiting exposure. Inner belt from 650KM (400 miles) out to 6300 KM (4000 miles). We spend nearly all of our time in space in LEO (Low Earth Orbit) 150 to 200 miles. Sattelites, especially geosynchronous, are built to withstand radiation and designed to shut down when it exceeds certain levels. The Apollo cabins were built with extra sheilding and minimum transit time. The Internations Space Station has multiple layers and the astronauts spend most of their time in the inner most sections.