There's enough atmosphere to produce 1 bar of pressure at sea level, and I believe from playing Universe Sandbox, a .320 Gauss magnetic field on the Earth. Maybe some portion of that would be enough to really protect space travelers well. How much material would you need to equal the atmosphere and how much power/electricity would you need to produce a similar magnetic field for space travel?

  • $\begingroup$ Look here how big the Van Allen belts of the earth are: en.wikipedia.org/wiki/Van_Allen_radiation_belt It is impossible to build a magnetic field of similar size and intensity around a spaced ship. $\endgroup$
    – Uwe
    Jun 10, 2016 at 12:39
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    $\begingroup$ @Uwe but the question only asked about it being of similar intensity. Using magnetic fields to deflect cosmic rays from spaceships has actually been examined. See this answer to Radiation shielding magnetic or mass, which is more efficient?. (By the way, if you got 4 more points by doing 2 edits on answers with spelling or grammar mistakes, you would have enough points to make comments, instead of posting things as answers when they aren't and the mods converting them to comments.) $\endgroup$
    – kim holder
    Jun 10, 2016 at 13:45

1 Answer 1


As well as Earth at sea level would be 14.7 lbs per square inch of a low-Z material. (You don't need the magnetic field.) E.g. a 34-foot thick shield of plastic.

  • $\begingroup$ @ Mark Adler. How much could be reduced the thickness of the shield in case that another material which has a better protection against radiation would be used? What would be the minimum of thickness by using the best option? $\endgroup$
    – Mark777
    Jun 10, 2016 at 15:37
  • $\begingroup$ I don't know that you can do much better in terms of density. You want a low-Z material to not produce hazardous secondary radiation, and their density tends to be about 1 g/cc. What you would want to do is figure out what level of health effects you are willing to tolerate, and then find the minimum thickness of low-Z material needed to meet that level. That is probably much less than 31 feet. Your spacecraft requirement would never be "as well as Earth does". $\endgroup$
    – Mark Adler
    Jun 10, 2016 at 17:31
  • $\begingroup$ Does that then mean that a material like Lead will get zipped by particles and produce secondary radiation? $\endgroup$ Jun 11, 2016 at 1:25
  • $\begingroup$ Well personally, I would want way more speed, some kind of centrifuge, and the most radiation protection reasonable. Those 3 things are, to me, a reason why human spaceflight hasn't left orbit in near 50 years (also producing those 3 things is mega expensive I'm sure). Maybe two modules of plastic could be launched and hooked up to block the Sun during your trip (like Mr Burns). $\endgroup$ Jun 11, 2016 at 1:27
  • $\begingroup$ I don't know what "zipped" is (other than data compression), but yes, lead is bad idea since the secondaries produced in the lead can be more biologically damaging than with no shielding at all. $\endgroup$
    – Mark Adler
    Jun 11, 2016 at 3:27

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