I don't think there is sufficient difference in the to/for to justify this usage. I would suggest a construction that reads more like
"The conquering of planet Mars is important to me because it's a great scientific achievement for mankind, however it will never have any impact in my life."
And does "to me" mean "in my opinion"? Do you agree with Jlinger, I mean do you think that the sentence doesn't demonstrate the difference between "to me" and "for me"?
Could you please suggest a phrase that demonstrates it?