Space Collition is having a Twitter contest that could get you an autographed poster by STS-1 Pilot, Robert “Bob” Crippen.The contest is pretty simple, all you have to do is watch the PSA video here (also at the bottom of this post). Then all you have to do is Tweet about it, and every 1000th Tweet wins a prize. Contest ends August 31, so don’t miss your chance!

Read more about the contest here.