I half agree with Gates. To me, sending probes into space deepens our understanding of nature and over time that knowledge will benefit humanity. But sending h

I half agree with Gates. To me, sending probes into space deepens our understanding of nature and over time that knowledge will benefit humanity. But sending humans into space is really just an exercise in human vanity, like climbing Mount Everest or placing a person at the bottom of the Mariana Trench. For the cost of sending a man to Mars we could send out two probes - one to Mars and one to Europa. Wouldn't that be better for science and humanity?