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Mars Explorers Face Huge Radiation Problem
astroengine writes "A radiation sensor inside NASA's Curiosity Mars rover shows that even under the best-case scenario and behind shielding currently being designed for NASA's new deep-space capsule, future travelers will face a huge amount of radiation. The results, based on Curiosity's 253-day, 348-million-mile cruise to Mars, indicate an astronaut most likely would exceed the current U.S. lifetime radiation exposure limit during one round trip mission. "Even for the shortest of missions we are perilously close to the radiation career and health limits that we've established for our astronauts," NASA's chief medical officer Richard Williams told a National Academy of Sciences' medical committee on Thursday."
So limit outdoor activity, and bury the colony shelters so that you can leverage inxpensive dirt for shielding.
Say, with sandbags packed with martian regolith.
(With a solar sintering machine, and "refined 19th century tech*", you could produce all the glass fiber sandbags you could possibly ever want on mars.)
* 19th century version
*refined modern and cheap consumer version
[For the imagination impaired, you use the solar sintering machine to produce a small, stationary bead of melted glass from abundant martian regolith, use a steel mandril to pull several glass fiber pulls off that bead, thread them through some eye-hooks in a halfcircle around the bead, then thread them through one last eye-hook as a bundle, and then feed the bundle into the knitting machine. Turn the crank, and a continuous tube of knitted glass fiber gets pooped out. Cut the "sock" at desired lengths, and use more glass fiber in a handheld bag stitcher to close the end, and stuff them with martian regolith. You can then stack them up to make 1950s style bunkers around the the habitat structures, which will not only keep the wind off of them, but also provide radiation shielding on the cheap for the colony. The total equipment needed would be well under 20kg, and would allow unlimited sandbag production at the colony site.]
Seriously, they already know how to deal with this, and discovered that hydrogen neuclei are ideal for absorbing high energy cosmic rays, since they produce a minumum of secondary high energy particles from the interaction. This means a substance with lots of hydrogen in a small volume makes the best shielding.
This leads us to the most abundant, hydrogen dense material available, which would also be necessary for the trip, and colony operations: water.
Basically, put the crew capsule inside the water storage tank. Radiation problem solved. You have to send the water anyway. Make the most of it.