My question is independent of particular halachic issues that a Jew would face on Mars. It is not even about the legality of the decision to move to Mars in light of the knowledge that many obstacles to observance may be insurmountable there. (See here and perhaps here. I would add that there are many, more obvious issues that aren't listed in the links--such as sakone, p'ru urevu/onah [at least one of these would have to be fulfilled on Mars, and both seem to be nearly impossible], bikur cholim, hachnosas kallah, sukkah, hachnosas or'chim, Shabbos/holiday/yahrzeit candles, and even possibly netilat yadayim, tzedakah/maaser/tevel, shofar, tefillin, getting rid of chometz, muktzeh, zecher l'churban, and who knows what others.)

It is more about whether anything in our sources addresses a hypothetical requirement to live on Earth. Although space travel may not have been explicitly foreseen nor prohibited, it does seem to me that very much of the Jewish worldview is based on the fact of living on Earth, and that hashkafically, there could be some problem. I keep coming back to the question of what will happen to those on Mars when Moshiach comes, for example. Are they still under Moshiach's aegis; will their lives change? Presumably, yes. But then, doesn't Moshiach's aegis have limits? It seems like a stretch to imagine that his coming will affect conditions on ULAS J0015+01, for example.

The one textual reference I can find for my question is this verse in Psalms (115:16): "השמים שמים לה' והארץ נתן לבני אדם"--"the Heavens belong to Hashem, but the earth He has given to man."

Can anyone bring any other Jewish sources, either for or against accepting a one-way ticket to Mars? (The connection need not be overt.)

Releated: What defines "on this earth" from a halachic standpoint?


1 Answer 1


Rav Menashe Klien was asked if one can say kiddush levana on the moon if they are physically on the moon. He answers in his Mishne Halachos 6:259 that there is no difference standing on the moon or earth with regards to saying kiddush levanah.

He then writes that going to the moon altogether should be prohibited for two reasons 1) the travel to the moon is dangerous 2) once one is on the moon they cannot breath without support (if they take helmet off). So he concludes it shouldn't be done and uses a passuk(Devarim 4:19 for a remez. This reasoning should apply to Mars as well.


  • Could you explain why not being able to breathe without support is a problem, Jewishly? Is it part of sekanos nefashos?
    – SAH
    Feb 1, 2016 at 13:24
  • Using life support on another planet means you're bringing earth with you to another planet. You can't, under current conditions, live outside of earth. Not sure what my point is though...
    – Shababnik
    Aug 13 at 4:04

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