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Extended space travel

  1. Nov 2, 2016 #1

    wolram

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  2. jcsd
  3. Nov 2, 2016 #2

    Jonathan Scott

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    It's already known that crews would need some way to shelter from radiation in case a solar flare occurred during the journey, as a single flare could give them severe radiation sickness. It has been suggested that it might help a lot to turn the spaceship end-on towards the sun in that case, with the crew at the end away from the sun. The new aspect is that even everyday exposure to cosmic rays could add up enough to cause problems, and one can't avoid that by means of turning in a particular direction. So either the crews would have to accept the risk of a certain amount of potential brain damage (!) or a new form of shielding might have to be developed.

    You might find this article interesting:
    http://www.spacedaily.com/reports/How_to_Protect_Astronauts_from_Space_Radiation_999.html
     
  4. Nov 2, 2016 #3
    A sufficient thickness of ice will stop most radiation threats from the sun.
     
  5. Nov 5, 2016 #4

    BillTre

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    But, how thick would be sufficient?
     
  6. Nov 6, 2016 #5
    That's math. I don't do math. However, consider the weight difference between a cubic meter of ice and a cubic meter of lead. The weight savings would allow a greater depth of shielding to be carried for the same energy expenditure.
     
  7. Nov 6, 2016 #6

    BillTre

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    Maybe they could pick some up in space and not have to launch it up.
     
  8. Nov 7, 2016 #7
    Definitely would be a good idea. And I suspect H2O is one of the most common chemical compounds in this universe.

    The gravity well penalty is a large part of what's keeping us from full-bore expansion into space now. Any way we can work around that is worth more than its weight in gold.
     
  9. Nov 11, 2016 #8
    The easiest solution is the one we already use - you end Moon missions in 1972 and stop sending people beyond low Earth orbit and let robots go exploring while everyone stays home. People have talked about human missions for 44 years, but they never actually do anything. The only extended human space missions are in TV and the movies and, in my opinion, it's likely to stay that way for a very long time.
     
  10. Nov 11, 2016 #9
    Pathfinder died on Mars because it couldn't fix itself. EOM Mark Watney (theoretically) survived on Mars because he could fix things. He completed the mission (as seen in the extended cut). Mission accomplished.
     
  11. Nov 14, 2016 #10
    The mission was intended to last between a week and a month. Pathfinder had a good run, it made almost made it to three months. When one robot "dies" we just send another, better machine to take it's place anyway.
    As I pointed out, the only success of this type we've seen so far is in fiction. When Mr. Damon has used his punctured glove to fly through space in real life and grabs Jessica Chastain's flailing hand in orbit around the real planet Mars, let me know.
    This pretty much underlines the reality of the situation, either we send a robot like Pathfinder (which excludes risking a human's life) or we declare victory in the realm of fiction. Either way, humanity has it's preferred solutions to extended the space travel concept. The public seems satisfied whether it's actual scientific data from a robot - "Hey! Pluto has got a heart on it!!" OR people are satisfied with speculation from the realm of science fiction "Hey! There's green women living somewhere in the constellation of Orion!"
     
  12. Nov 14, 2016 #11
    And they'll continue to die for possibly trivial reasons. Humans can do better.
    Before I wore khakis I was in charge of fixing things that broke on my ship. I saw Matt as doing the same thing on Mars. It's really not that different. "You just begin."
     
  13. Nov 14, 2016 #12

    mheslep

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    Not theoretically, fictionally. Very different things.
     
  14. Nov 14, 2016 #13

    mheslep

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    The analogies are way off. One does not examine the problem of crossing the ocean and conclude swimming has a shot because they have great determination. Setting foot on Mars and coming back is not like fixing a ship.
     
  15. Nov 14, 2016 #14

    BillTre

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    Apollo 13 could be considered a fix-it case in space (also a movie!).
    However, one could also argue that all that was done to save the craft would not have been necessary if the were no people aboard and no people would have been put at risk.
    On the other hand, its unlikely the mission would have happened without the people due to technological limitations.
    On the third hand, technological advances have shifted the threshold for when it makes sense to send people (when current technology can't be expected to handle things sufficiently well.
     
  16. Nov 14, 2016 #15
    You get half a hair, I get the other half.
     
  17. Nov 14, 2016 #16
    Okay then.
     
  18. Nov 14, 2016 #17

    mheslep

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    Fiction and theory? Half a mountain.
     
  19. Nov 14, 2016 #18

    phinds

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    I think it's more like fiction gets half a hair, theory get half a mountain.
     
  20. Nov 14, 2016 #19
    The hairs are fully split.
     
  21. Nov 15, 2016 #20
    Humans have been doing better, we've built better machines that have been more successful as technology progresses.
    Sadly, humans have already died from "trivial" causes. To me the comparison goes like this:
    The Mars Polar Lander goes to Mars and NASA never hears from it again. The result is one lost piece of junk.
    A valve is jolted open on Soyuz 11. The result is the deaths of three people.
    Whatney's statement at the end of the film in question - that if you can solve all the problems you get to go home - is rather simplistic. Real life doesn't necessarily work that way. There are Apollo 13 situations where the problems were solved as Whatney describes and they did indeed survive. However, the crews of the Challenger and Columbia shuttles undoubtedly tried everything to save their lives and those missions were only in low Earth orbit.
    The bottom line is this - the last four decades show that humans prefer to explore the Solar System remotely from the relative safety of Earth. Remote exploration is also far more cost effective for extended space journeys. Therefore any extended space missions shouldn't have to worry about people being exposed to radiation - robots can be made to withstand radiation and they are our preferred method. Hollywood actors should also be safe since they operate in the world of make believe.
     
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