For extremely long journeys, deterioration of spaceship materials becomes a concern beyond mere rust or corrosion.

Assuming a ship is sufficiently protected against radiation and other colliding objects

  • What materials would be problematic in terms of naturally decaying into different atomic elements?
  • Can anything be done to prevent said radioactive decay?
  • $\begingroup$ This question might be better written to ask what the best materials would be, rather then the worst. Pretty much everything is bad for million year space journey. For example all of the metals would be subject to metal fatigue issues much sooner then worries about radioactive decay. $\endgroup$ Jul 19 '13 at 16:06
  • $\begingroup$ Wouldn't that change the question from one about radioactive decay to one about other issues (e.g. metal fatigue?) $\endgroup$ Jul 19 '13 at 19:14
  • $\begingroup$ @JerardPuckett Your edit suggestion is too extensive and against the wishes of the OP. It would be better if you created a new question. $\endgroup$
    – called2voyage
    Feb 4 '14 at 18:37
  • $\begingroup$ It occurs to me that this question is indeed about space exploration and should be reopened. If a ship is intended for interstellar journeys (say we made a Viking 3), nuclear transmutation is worth thinking about. I understand that there are other issues that come up before transmutation, but I don't believe there are rules that a question must deal with more likely challenges before considering more difficult ones. If anyone thinks otherwise, how can the post be edited to conform to the rules as well as the original intent of my question? $\endgroup$ Feb 4 '14 at 21:49
  • $\begingroup$ @brentonstrine The close reason isn't perfect. It should be "too broad" rather than "off-topic". As pointed out by James Jenkins, there are far too many materials that meet the qualifications of your question. A better question would be "How could you design a spaceship to avoid issues of radioactive decay and transmutation on a million year journey?" $\endgroup$
    – called2voyage
    Feb 5 '14 at 19:36

As shown by this table from Wikipedia there really are not any natural elements that are appropriate for building a space ship where radioactive decay is significant issue, eight of the most stable radioactive isotope/elements have half-lives of over four million years. Most of the elements don't have meaningful half-lives in a million year period.

  • $\begingroup$ Thanks for the link to that chart. Just what I was looking for! However, it indicates that the blue elements "contain at least one stable isotope" and it doesn't mention a half-life for those. Does this mean that those elements will not transmute? $\endgroup$ Jul 19 '13 at 20:58
  • $\begingroup$ This link en.wikipedia.org/wiki/List_of_elements_by_stability_of_isotopes addresses that question, but essentially there are both stable and unstable isotopes of all elements. There are a lot of variables and if you work at it hard enough you could probably have any element in the lower 82 that is all stable or unstable isotopes. $\endgroup$ Jul 19 '13 at 22:27

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