"Jesuit Brother Guy Consolmagno, director of the Vatican Observatory, said the question of life beyond Earth is "a question of faith."   While there is no definitive proof yet that extraterrestrial life exists, "our faith in the fact that life exists is strong enough to make us willing to make an effort in looking for it,"

In Catholicism, a concrete act of faith would be related to matter of  which there's no evidence, and which actually repels our intellect.  For example, faith in the Trinity.  

But scientific "faith" that life may be discovered on other planets has nothing to do with religious faith.   Rather it's a surmise that's built upon revealed empirical evidence -- in this case, the sheer number of planets where conditions for life are materially possible.