The goals of astrobiology are three, according to this video by a pioneer in the field of atheist astrobiology, David Morrison. Astrobiologists seek to answer these questions:
1. How did we get here?
2. Are we alone?
3. Where are we going?
My contention is that these are not questions that can be answered by science, because they depend on the unseen. The answers that astrobiologists will get depend on the axioms they use. If the axioms are wrong, the answers will be wrong. Atheism necessarily uses wrong axioms.