Don McLean

Herman Melville was supposed to be an accountant. Van Gogh was meant to be an art dealer. I was meant to take the train into New York and work for a bank. To be an artist, you have to say goodbye to your family.

Running fills the cup that has to pour out for others. Running feeds the soul that has a responsibility to nourish. Running sets the anchor that limits the drift of the day. Running clears the mind that has a myriad of challenges to solve. Running tends to the self so that selfishness can subside.

Supplying fuel for a Mars expedition from the lunar surface is often suggested, but it's hard to make it pay off - Moon bases are expensive, and just buying more rockets to launch fuel from Earth is relatively cheap.