The radiation showstopper for Mars exploration

Posted: June 6, 2019 by oldbrew in cosmic rays, exploration, Travel, Uncertainty
Tags:

Mars-Earth comparison
[image credit: Wikipedia]


A manned trip to Mars is not looking like a good idea from a health point of view, according to this report.

An astronaut on a mission to Mars could receive radiation doses up to 700 times higher than on our planet—a major showstopper for the safe exploration of our solar system, says Phys.org.

A team of European experts is working with ESA to protect the health of future crews on their way to the Moon and beyond.

Earth’s magnetic field and atmosphere protect us from the constant bombardment of galactic cosmic rays—energetic particles that travel at close to the speed of light and penetrate the human body.

Cosmic radiation could increase cancer risks during long duration missions.

Damage to the human body extends to the brain, heart and the central nervous system and sets the stage for degenerative diseases. A higher percentage of early-onset cataracts have been reported in astronauts.

“One day in space is equivalent to the radiation received on Earth for a whole year,” explains physicist Marco Durante, who studies cosmic radiation on Earth.

Marco points out that most of the changes in the astronauts’ gene expression are believed to be a result of radiation exposure, according to the recent NASA’s Twins study. This research showed DNA damage in astronaut Scott Kelly compared to his identical twin and fellow astronaut Mark Kelly, who remained on Earth.

A second source of space radiation comes from unpredictable solar particle events that deliver high doses of radiation in a short period of time, leading to “radiation sickness” unless protective measures are taken.

Europe’s radiation fight club

“The real problem is the large uncertainty surrounding the risks. We don’t understand space radiation very well and the long-lasting effects are unknown,” explains Marco who is also part of an ESA team formed to investigate radiation.

Since 2015, this forum of experts provides advice from areas such as space science, biology, epidemiology, medicine and physics to improve protection from space radiation.

“Space radiation research is an area that crosses the entire life and physical sciences area with important applications on Earth. Research in this area will remain of high priority for ESA,” says Jennifer Ngo-Anh, ESA’s team leader human research, biology and physical sciences.

While astronauts are not considered radiation workers in all countries, they are exposed to 200 times more radiation on the International Space Station than an airline pilot or a radiology nurse.

Full report here.

Comments
  1. A C Osborn says:

    It is a case of providing enough radiation proofing of the Vehicle, which means lots of launches of “Lead Shielding”.
    The weight won’t matter to the vessel once it is in space. They can also distribute their water in the walls as well.
    Living on the surface would be the biggest problem, they would have to dig down, most of which could be done by robots before they even get there.

  2. Bloke down the pub says:

    A handy lava tube to build your Mars base in is always useful.

  3. ivan says:

    The question I have not seen an answer to is, what is the actual measured effect of this radiation on the human body? Until they have an actual answer to that question all their deliberations are just speculation, just like the climatologists waffling about climate change or whatever they are calling it today.

    The other thing is just an engineering problem as pointed out by A C Osborn.

  4. hunterson7 says:

    The environment of space is the harshest we have yet dealt with.
    It appears that the challenges can be dealt with but we still know so little.
    Could a magnetic field be generated to deflect enough radiation to help deal with danger, yet not interfere with electronics and communication?
    What is the lowest limit of microgravity that will mitigate the problems of weightlessness?
    What lightweight materials exist that can shield from radiation?
    If I recall correctly, polyester, believe it or not, is used to shield nuclear power plants on submarines and even satellites
    https://www.sciencedirect.com/science/article/pii/S025405841830765X

  5. That’s why the scheme to colonize Mars in surface stations was always a scam; they collected lots of money but knew they could not make this work.

    If we want to learn to colonize another planet we need to do the Moon first. We can get people there without killing them, and then learn how to do it in a place where we can come home if we have to.

    Either that or we need a much, much faster propulsion system.

  6. willybamboo says:

    It’s an evolutionary non-starter. No species is in charge of its development. The critical mass of organisms needed to successfully mutate (or resist) and survive is impossible to achieve. No pun intended. Man can not live on other planets.

  7. gbaikie says:

    Well a solar flare could kill crew in ISS if they didn’t have enough shielding and same applies if going to Mars.
    So what do ISS crew do when solar flares occurs?
    ” “The ISS crew did receive a Solar weather warning several times and were advised to enter the more protected areas of the ISS, such as the US built Destiny laboratory, or the Russian built service module Zvezda”

    How are these modules protected – what shielding or other measures make them safer than the rest of the station?”
    https://space.stackexchange.com/questions/14709/how-does-iss-protect-astronauts-from-coronal-mass-ejections/14713
    One answer:
    “The two specific modules are protected by two mechanisms:

    TeSS Polyethylene radiation protection tiles and bricks
    Water storage bags attached to the walls making a “water wall” ”
    ….
    “Future deep space missions propose to utilise water storage walls as part of their design following from experiences on the ISS.”

    So, 1 crew requires about 10 tons of water per year.
    Average US citizen uses in total about 2000 tons of water per year- but includes
    all water use- to make food, water lawn, power generation, etc.
    But everyone uses more than 10 tons per year for cleaning and personal use.
    Instead spending energy and mass recycling water use, you could use less mass
    for recycling water, and simply bring more water. But if you just bring 10 tons of
    water, that could used for shielding. And you can keep all waste water/sewage instead
    dumping it into space.
    So not counting solar flares, you travel to Mars without being killed or increase chance of
    damage by much. But you have have shielding or a solar flare could kill all the crew within short period of time. So need a solar flare shelter. Something all crew could go to for periods of days
    duration [though perhaps it’s cramped quarters]. So could make a bigger solar flare shelter or have entire vehicle be solar flare shelter.
    So you could a moderate amount shielding for entire vehicle and a lot shielding for solar flare shelter- all crew sleep in a shelter.
    Now if even solar flare shelter will not prevent GCR. The purpose of shelter is to prevent death or sickness within days of exposure. Or pick worse the worst solar flare, and design it so crew would not die or get very sick from it, and GCR goes thru more than a meter of concrete or water.
    So the problem is reducing months [or years] duration of high levels of GCR.
    And a problem with GCR is that something like thin layer of lead can increase the amount radiation due to secondary radiation caused material like lead, aluminum, or just about anything other than hydrogen. So, TeSS Polyethylene or water has a lot hydrogen in it. Though small amount of GCR is not hydrogen [protons] travelling near light speed- iron nucleic can also travel at near lightspeed.
    So a hydrogen compound does stop or reduce the radiation effect from a iron nucleic. Cf:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5771487/
    [complicated]
    Broadly, a problem with GCR is traveling during solar minimum AND the long transit times of going to Mars.
    So obviously have enough shielding. And if have a choice don’t travel during solar min- which could quite problem if we entering a Grand Min.
    And other solution is to get to Mars quickly.
    On the mars planet, you half the rate simply because you on planet, or simply being in orbit reduces it. Plus one easily use lots of shielding at the mars surface.
    A another solution is using a Mars Cycler. A heavily shielded spacecraft which does enter Mars or Earth orbit. You dock with it during long travel time and leave it, and enter Mars orbit and go to Mars surface. A Mars Cycler could also be designed to provide artificial gravity.
    But I think getting to Mars in 3 months with the crew is a cheaper option- in terms human exploration- NASA Mars exploration program.
    Mars settlements might be better with a Mars Cycler.

  8. BoyfromTottenham says:

    Gee, didn’t they think of that before funding this boondoggle? Who’da Think?

  9. Tom Abbott says:

    We need radiation-shielded, artificial-gravity habitats in orbit around the Moon and Mars in order to safely explore and exploit these bodies.

    We need the same for vehicles traveling between the Earth and Mars.

    The simple way to do this is to take two habitation modules and put one at each end of a mile-long cable, then have the modules orbit the common center at one revolution per minute and this will generate artificial gravity (centrifugal force) in the modules at the ends of the cable equivalent to the gravity of the Earth’s surface.

    Covering the modules with a coating of water ice one meter thick will protect people inside from space radiation.

    The Moon and Mars are places to explore and work, not places for long-term human habitat.

    Artificial habitats in space are the future of the human race in space. Unless something drastic like discovering faster-than-light travel were to come about. Were that to happen, then the human race could probably find a lot of planets in the galaxy suitable for humans.

    If we ever find out if UFO’s are real, the universe better look out! That’s all human beings need to know is that traveling between stars can be done. If they know that, then they’ll figure out how to do it eventually. 🙂

  10. dscott says:

    I’m going to question the tonnage of water needed for radiation shielding. Every time I hear of going into a safe room as it were, it conjures the image of being surrounded on all 6 axes/sides (or 360 degrees if a sphere) by water. IF a solar flare is coming from the sun, then it stands to reason only one side is needed to block the radiation from the flare as in an actual shield wall shape approximately 5 meters in thickness blocking the line of sight between the crew and the sun. The water need not be in liquid form either, it could be a structure made of ice.

    Radiation protection discussion: https://space.stackexchange.com/questions/797/radiation-shielding-magnetic-or-mass-which-is-more-efficient

    “If the material is water, it has to be five meters deep.”
    http://www.dartmouth.edu/~sshepherd/research/Shielding/docs/Parker_06.pdf

    They also speak of ethylene C2H4 polymerized into polyethylene as another means to block cosmic rays or high energy proton ions. A shield built of layers of polyethylene blocks and water ice would be a lighter weight. By keeping the shield facing the sun at all times it could also serve as a convenient surface for a solar panel which would shade the protective shield from the heat of the sun.

    Also, any sewage/waste water not recycled could be pumped to another shield layer tank parallel to the ice and polyethylene.

    This is a straight forward engineering solution.

  11. dscott says:

    Something else struck me, if water can be used as a shield then compressed air could equally be used:

    Contrary to popular belief, it is not Earth’s magnetic field
    that shields people on the ground from the full brunt of these
    rays but rather the bulk of our atmosphere. Above every square
    centimeter of surface is a kilogram of air. It takes a vertical
    column of about 70 grams—about 1/14 the distance through the
    atmosphere, achieved at an altitude of 20 to 25 kilometers
    (60,000 to 80,000 feet)—before the average incoming proton
    hits the nucleus of an atom in the air. The rest of the atmosphere
    serves to absorb the shrapnel of this initial collision.

    Create a wall of compressed air as a shield since you need to store spare breathing air as well.

  12. oldbrew says:

    dscott – cosmic rays can come from any direction.

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