“The impetus behind SpaceX” according to biography:
http://www.dailymail.co.uk/sciencetech/article-3082067/Russian-space-bosses-SPAT-Elon-Musk-tried-buy-rocket-persuading-build-new-book-reveals.html
Interesting. That is how Boeing got started too. He wanted to buy a plane and decided he could build a better one.