Space Cowboys High-profile entrepreneurs pursue the final frontier.

When several of the world's most notable entrepreneurs allseem to agree where the next big business opportunity lies, youhave to pay attention. But what if they're all startingcompanies to provide space transportation to tourists?

The question is highly relevant today, as a gaggle of marqueebusiness creators line up to invest sizeable fortunes in goingwhere no profit-making business has gone before. The list includesMicrosoft co-founder Paul Allen, Amazon.com founder Jeff Bezos, Virgin founderRichard Branson and Elon Musk, who co-founded PayPal and sold it toeBay for $1.5 billion.

Space isn't as unlikely a source of profits as it may seemaccording to Musk, whose Space Exploration Technologies in El Segundo,California, plans to launch its first space vehicle this year. Thedevelopment costs--as much as $100 million--will be recouped bylaunching satellites for communication companies and governmentagencies at first, Musk says. SpaceX, as the company is known, willcharge $5.9 million per shot of the smaller of the two rockets itplans to develop, and $15.8 million for the larger one. Bothfigures are substantially less than going launch rates.SpaceX's first customer is the Department of Defense, for whichit plans to send a $30 million satellite into orbit.