Rabbinical scholars have been interpreting the Talmud for centuries, to provide a framework for applying its strictures to everyday situations, and guidance to rabbis who must answer questions from their congregation.

Purely theoretical questions aren't given as much priority, but they are often pondered as well, for intellectual stimulation, if for no other reason. But on the next Shuttle flight, the theoretical becomes real. An Israeli astronaut will be aboard, and he wishes to be observant. There have been Jewish astronauts before (Americans), like Judy Resnik, who was killed in the Challenger disaster, but this is the first time that an astronaut is going to attempt to "keep kosher."

So the question arises: when you're in orbit, and the sun rises and sets every hour and a half, and the stars are in view all the time--when does Sabbath begin and end?

He asked his rabbi, and the matter is under discussion.

[Thanks to Kevin McGehee for the tip.]

The Rabbis quoted in the link seemed unimpressive. There are plenty of doctrines in the Talmud to resolves these issues. Sadly, politics and fear often trump Talmudic discourse when new scientific advances come up for halachic review (rulings of Jewish Law).

When electricity became common, there was much discussion about how it can be used. Rabbis with a more scientific bent argued that it should be allowed. Other, more cautious (backward? Luddite?) Rabbis argued that electricity = fire (because the lightbulb was the first common use) and therefore forbidden on the Sabbath. The fact that electricity was just part of the process, the fact that a lightbulb has a vacum to prevent the filament from catching fire - they didn't want to hear it.

If you ask a modern day Rabbinical scholar about the counter arguments to electricity = fire, they will tell you there aren't any. Those opinions weren't taught in school, and the Rabbis who held contrary views kept quiet when the became famous later.

Your link shows the same thing over again. I see it in the prattlings of the Rabbis quoted. A visionary can see that the problem needs to be solved NOW, before space colonies start for real. But these guys prattle on.

There are a few easy solutions for which I could find ample Rabbinic precedent. They could rule that the Sabbath is observed based on the date/time of Jerusalem. The could rule that it is based on the destination date/time of Sabbath, or the departure date/time of Sabbath. In the case of a colony, the Sabbath could be pegged to the local day rotation.

The fact that I could give Talmudic cites for these positions is irrelevant. All these positions would require the Rabbi to go out on a limb, which they will nver do. Maimonides (http://www.us-israel.org/jsource/biography/Maimonides.html) is spinning in his grave.

What do observant Jews in the Israeli Navy do on the Sabbath? (Or on merchant vessels, for that matter?)

Hmmm ... and what do observant Jews do about crossing the International Date line? Seems to me that there ought to be a bunch of terrestrial precedents already.

I'm pretty sure these questions have already been asked and answered regarding observant jews above the arctic circle and in Antarctica. I believe in Antarctica, they use Shabbos times based on the nearest jewish community, which I think is in New Zealand. In space using the times from Cape Kennedy or Jerusalem are both possibilites.

Word to Martin Devon.