My qiyas (qiyas only. I'm neither an analyst of fiqh nor can I issue a fatwa) would be the following, in the end Allah knows the best.
Regarding position/method of salah
Rules of handicapped or disabled person applies to an astronaut. Perform salat however possible.
Are there any such rules in the Quran? Do we perform or establish salah?
2.Time of salah
All their daily activities are divided by 24h period regardless of their days being only about 90 minutes. For ISS for example, they follow times of (at least) both Houston,Texas,USA and Moscow,Russia. The way I see it, they have about 16 opportunities a day for each salat (16 times for one fajr in 24h, 16 times for one zuhr in 24h and so on). I think this is the fundamental concept that's debatable.
There is no mention of 24 hour period for salah.
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Sahih International
And establish prayer at the two ends of the day and at the approach of the night. Indeed, good deeds do away with misdeeds. That is a reminder for those who remember.
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Sahih International
Establish prayer at the decline of the sun until the darkness of the night and the Qur'an of dawn. Indeed, the recitation of dawn is ever witnessed.
So choose 12am of Houston or Moscow to count your 24h period. Perform fajr at when it seems dawn from ISS. One has to be very quick for fajr as s/he gets only about 2 minutes. Then at the same or different 90 minute cycle, perform zuhr at appropriate time from ISS (not Earth time). The time duration of zuhr and asr (also maghrib and isha) may be considered as one (like the day of Arafah) for convenience.
There are some situations in outer space that I can't even imagine a solution for. Would things be different if one orbits the Earth east to west (sunrise would be from the west and sunset in east)? What about for long distance journeys in outer space, for example 3 day journey to moon or 6 month journey to Mars? What should be the rule of fasting up there?
East is the place of rising of the sun so it does not matter which direction you are going.
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Sahih International
Have you not considered the one who argued with Abraham about his Lord because Allah had given him kingship? When Abraham said, "My Lord is the one who gives life and causes death," he said, "I give life and cause death." Abraham said, "Indeed, Allah brings up the sun from the east, so bring it up from the west." So the disbeliever was overwhelmed , and Allah does not guide the wrongdoing people.
I leave it to your qiyas brother.
Rules of fasting can be a different topic.
Brother see my replies in red above.
