Like many 20-somethings, Cole Leonard has reached a professional crossroads: Should he pursue a safe career? Or strive for a dream that may prove elusive? But few of his peers face a choice this stark. He's deciding between becoming a lawyer or dying on the surface of Mars.

It's a difficult decision for the 27-year-old from Plano, Texas. Leonard has been accepted into law school at Texas Tech for the fall. But he is also one of 705 candidates vying to be part of the first human colony on Earth's neighbor.

The journey is being organized by Mars One, a nonprofit founded by a Dutch entrepreneur who insists it can be accomplished with current technology. Each colonist would undergo at least eight years of training. They'd learn about space travel and how to live on a planet with vicious dust storms, low temperatures below minus 200 degrees and a lack of breathable air.

And there's this one big catch: The technology doesn't exist to launch a return flight. It would be a one-way trip.

That sounds like a good deal to Leonard, though he doesn't much fit the bill of an astronaut. He works as an aide to Dallas County Commissioner Mike Cantrell. He doesn't have much training in flight, engineering, agriculture, medicine or any other skills helpful to sustaining life on another planet.

But in other ways, he says, he's perfect. He is young, healthy and single. He has always been interested in space and science fiction. And, more important, he is enamored of the idea of exploring — and the need for humankind to broaden its horizons. Plus, he would leave behind an identical twin on Earth. "I'm expendable," he said.

Still, there's some hesitation. Before leaving Earth, he'd need to know more about the technology and contingency plans. He'd hate to run out of food or power or water 34 million miles from home.

Mission founder Bas Lansdorp, who made his fortune building a wind energy company, has estimated that it will cost $6 billion to send the first group of four. He hopes to raise much of that through a reality TV show, which would broadcast the training, the trip and the landing.

Leonard said he understands that law school would be a more practical choice — and he's hesitant to give it up for what may be a quixotic dream. But certain death on Mars doesn't scare him. Death is certain everywhere. "I am going to die here in some crappy retirement home in Florida," he said. "Why not Mars?"