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Radiation levels on Mars won't deter exploration, NASA says

By Catholic Online (NEWS CONSORTIUM)
May 31st, 2013
Catholic Online (www.catholic.org)

The question arises. How safe would a mission to Mars really be? Long periods of space travel, perhaps years  in a cramp compartment with no breakdown cover, future spacemen will need to acknowledge that their bodies will be zapped by high-energy particles, raising their risk of contracting cancer and other ill effects of radiation. Even then, the will to explore will remain and travel to other worlds will continue regardless.

LOS ANGELES, CA (Catholic Online) - Earthlings are routinely exposed to natural radiation from a variety of sources, including Brazil nuts, bananas and invisible radon gas. Earth's magnetic field largely protects its inhabitants from untoward radiation. The field is carved into a teardrop-shaped bubble, also known as the magnetosphere by the solar wind that blows from the sun.

The magnetosphere's overall effect is to shield life on Earth and astronauts in low Earth orbit from effects of cosmic radiation. Earth's atmosphere provides an additional buffer against all but the most energetic of particles. Astronauts traveling outside the magnetosphere will need to rely on the shell of their spacecraft to protect them from danger.

NASA's rover, Curiosity, which landed on Mars last August, is carrying an experiment to measure radiation levels.

The latest news from the Red Planet highlights the fact that had astronauts taken the same journey, their radiation exposure would have reached two-thirds of the maximum, career-long dose set by NASA in less than a year. Radiation protection is a serious issue that needs to be addressed for prolonged visits to the moon, the journey to Mars, and for other deep-space missions such as NASA's plans to visit a near-Earth asteroid.

The two chief sources of cosmic radiation are: 1. Cosmic rays, a near-constant rain of high-energy particles arriving from elsewhere in our galaxy, and 2. sporadic bursts of particles from the sun, called solar energetic particles. Major risks can be minimized by traveling during the quietest phase of the sun's 11-year activity cycle.

The most practical approach to protecting astronauts currently is to build a highly shielded module into the design of the spacecraft, i.e. a storm cellar. The radiation measurements from Curiosity show that a large proportion of the total exposure occurred during periods following solar flares, with quiet periods in between.

If astronauts are able to shelter for a few days when necessary in a well-shielded module, they're likely to avoid the worst effects of solar energetic particles.

The danger won't recede away on Mars. There are several regions on the planet where local magnetic fields provide some protection, but astronauts will ideally need to bury their living modules for additional protection during extended visits.

While highlighting the risks posed by radiation, NASA will almost certainly deem the Curiosity measurements to be within manageable levels . and the will to explore will prevail.

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