That assumes Orthodoxy is irrelevant.
If sentient alien life were discovered, what would the implications be for the Orthodox Church?
It would hasten Orthodoxy's plunge into irrelevancy.
What is the implication if no sentient life is ever found, or more, it is found no sentient alien exists?
I don't think Orthodoxy is totally irrelevant, I just think it is moving in that direction. Orthodoxy used to be all about "baptizing" pagan customs, meeting intellectual opponents head on, and transforming individual lives. Now it's just about the last one, and unable or unwilling to do the first two. True, every once in a while you will get someone who is Orthodox that will engage the surrounding culture: maybe this person is interested in bioethics, maybe that person is interested in using his past experience in punk music to do missionary work. But these are exceptions to the rule.
Regarding your question, as with 90% of the evidence for or against religion, God, etc., I would certainly take into consideration such findings, but I don't think it would be a strong mark in favor of either side (though I admit that I haven't thought about it much).