I've wondered about this myself

From Australia:

Muslim scientists and scholars will be discussing Islam and life in space during a two-day conference which opens in Malaysia today.

The meeting aims to answer some of the questions faced by would-be Muslim astronauts about how to meet the requirements of their faith while in orbit.

Malaysia is due to send an astronaut into space with the Russians next year and it is almost certain that the country's first spaceman will be a Muslim.

That raises plenty of questions.

For instance, water is a precious commodity in space and Muslims must wash before they pray.

Likewise, the faithful face Mecca while at prayer but that will involve trying to pinpoint a moving target while in zero gravity.

Prayer times for Muslims are linked to the times of the sunrise and sunset, but in orbit the sun appears to rise and set more than 12 times a day.

Malaysia's Science Ministry has called together a group of experts to thrash out all these and more in what has been billed as the first serious discussion of the issues.

There's more to it than just recycling and prayer in orbit. What about a trip to mars, when the sun is visible for the entire trip? Or the moon, with a month-long "day"? And what exactly are the status of prohibitions when they apply to "any place on earth"? At one time it was suggested than wealthy Muslims might be a market for orbiting pleasure palaces, where drinking and gambling could take place without violating the letter of the law. (The orbitals turned out to be unnecessary--the wealthy ignored the rules in London and Monte Carlo, while pretending to be nothing but pious at home.)

This isn't only a problem for Islam, of course. Most of the fundamental religious texts assume the earth is unmoving and at the center of the universe. The catholic church, to its credit, is at least thinking about the theological implications of life (especially non-human intelligence) on other worlds, and it has the advantage of having a single decision maker to announce official changes in theological interpretation. But Islam doesn't have a Pope. It's still at a point similar to the Christian diets and convocations to determine which books belong in the Bible, or if Jesus was in fact divine. People died over those issues, like they do in the ongoing Islamic "civil war," but eventually things worked out. Today, however, there is one important difference--none of the early Christians had weapons of mass destruction.