The three reasons are 1) it&#x27;s where the science is, 2) it&#x27;s where the challenge is, and 3) it&#x27;s where the future is.<p>This is further described as 1) if we find fossils, or don&#x27;t find fossils, then it helps us understand abiogenesis, and if we drill and find life then we can understand biology better, 2) it&#x27;s a &quot;bracing challenge for our society&quot; that will drive a new generation of scientists, engineers, and doctors, and 3) we need new branches of humanity on Mars, just like the European settlement of the Americas.<p>He does not (in that short clip) explain why <i>humans</i> need to be on Mars to do the science.