The discussion in Malaysia should give us all an idea about why muslim countries remained backwards so many centuries. Actually a non-sense discussion, and I do not think that those theologians will reach an easy and practical conclusion but in Islam there is a saying: God is neither above in the skies(or heaven) nor in somewhere else, but God is everywhere and he/she (dunno what is God) is closer to you than the blood in your veins so it would not matter the direction you make your prayers. We, muslims pray 5 times a day (in the morning, before sunrise, in the noon, after noon, in evening and at night not 80 times

) and aim with these prayers is being closer to God. Every faithful muslim tries to perform his/her prayers and if the mentioned astronauts are faithful then they also will try to to not to give up their prayers. Well on Earth, we have to face to direction of Mecca during our prayers (or Salat in Arabic, or Namaz in Persian) which is a tradition AFAIK but in the space this will not apply, and if I was to do my prayers I just would face Earth, I do not think that God would reject my prayers. What is important in Islam is the intention not the WAY you do it. Besides God is the most mercifull. I think I clarified some issues in my non-muslim friends

If u have any questions about Islam, I can answer.