Inspired by this question.
The question linked quotes Sanhedrin 59b in saying that if an animal came down from heaven (whether it had kosher signs or not) it would be kosher.
If I were, however, to make a pig farm on the moon, there is no descending from heaven. The source of this pig is very much known, in contradistinction to the case in the gemara where the 'animal of unknown origin' descends from heaven. I imagine that, since it is brought down from heaven, Hashem has 'sent' it and it is therefore okay to eat.
However, in this case the source of this food is certainly known - a non-kosher Earth pig. You may say that since it hasn't 'fallen from heaven to Earth' then this is not the case that the gemara deals with. However, doesn't the law of 'split hooves' and 'chewing the cud' apply to land animals i.e. on Earth. Could it be that even pigs born on a pig farm on the moon would be kosher because of this?