Apollo XI and Gemini 12 astronaut and Korean War fighter pilot Buzz Aldrin hosted an #AskBuzz event at Twitter headquarters today. What most people seemed to want to know was where to get one of those cool “Total Recall” inspired “Get your ass to Mars” T-shirts that Aldrin was sporting. (Just FYI, they’re available at his website.)

Aldrin answered several questions in exchange for a favor to be asked later.

The favor? Provide some suggestions on how to get the next president to commit to a mission to Mars by the 50th anniversary of the moon landing.