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Rabbi Ben-Zion Firrer asked whether Torah Law must be observed in space, since Deuteronomy 12:1 says one should follow the Commandments "all of the days which you are alive on this earth."

What defines "on this earth" as it relates to the halachic necessity of performing mitzvot?

Presumably the earth's atmosphere would count as "earth," but why? You are not literally "on [the] earth" when you are in the atmosphere.

And what about Space outside the atmosphere? Do the Commandments not apply there?

From a logical standpoint, it seems absurd that one might be allowed to murder or worship idols while aboard an airplane, or a rocket ship, for that matter. But does halacha itself account for these situations in any reliable way?

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One perspective mentioned in the answer I linked above is that of Rabbi Shlomo Goren, who reasoned that (according to the answer): "since one cannot survive in the environment of space without bringing earthly oxygen and water with him, he is still 'on this earth' for purposes of this, now, very real discussion." –  SAH Mar 13 '13 at 18:31
I wonder if this can be interpreted along the lines of Ramban's position that Eretz Yisrael, in particular, is the primary place for observing all mitzvot. Perhaps that's what "on the earth" means here, too? –  Isaac Moses Mar 13 '13 at 18:36
I remember seeing that Rav Menashe Klein held if one was on the moon itself he would say kiddush levana. –  sam Mar 13 '13 at 18:39
@sam, that's not exactly a Mitzva –  Isaac Moses Mar 13 '13 at 18:41
What about shooting someone while jumping? –  Shmuel Brin Mar 13 '13 at 19:37
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