Every time the subject of one-way Mars expeditions comes up, it reminds me, in a perverse way, of Ambrose Bierce's great Civil War story, "Parker Addison, Philosopher."
If you don't want me to spoil the ending, read it here. But in summary: A captured Union spy is all bluster and cool self-confidence when he thinks he'll be executed the next morning. But when the Confederate general calls his bluff and orders that he be taken out and shot immediately, the spy freaks out.
Now substitute "execution at dawn" for "sending people to Mars." When it comes to human Mars missions, launch day is always a safe 20 years in the future. Really, we're in no hurry at all. In fact, we give every sign that we'd rather just keep talking about it. So, presented with the idea of a Mars trip we could actually start working on now, old-schoolers like Cernan either dismiss it out of hand or, like Parker Addison, freak out: "Wait, whoa! We can't possibly do that!"
For those who say the ultimate goal of human spaceflight is to establish settlements off Earth, authors Paul Davies and Dirk Schulze-Makuch may have just called your bluff. They suggest an approach that's cheaper and logistically easier than the traditional Apollo-style round trip. Supplies and equipment would be sent ahead of the settlers, who would have all the resources they need to live off the Martian land when they arrive. It wouldn't be a suicide mission, as Cernan claims. But it would be a commitment. As Davies and Schulze-Makuch write: "The situation these first Martian settlers are in, who would of course be volunteers, would really be little different from the first white settlers of the North American continent, who left Europe with little expectation of return."
The idea of one-way space journeys is not new: It's been proposed for Mars before, and was even suggested in the early, how-are-we-going-to-do-this? days after President Kennedy committed the nation to a moon race in May 1961. Here's an excerpt from the NASA history, Chariots for Apollo:
Another approach was the proposal to send a spacecraft on a one-way trip to the moon. In this concept, the astronaut would be deliberately stranded on the lunar surface and resupplied by rockets shot at him for, conceivably, several years until the space agency developed the capability to bring him back! At the end of July 1961, E. J. Daniels from Lockheed Aircraft Corporation met with Paul Purser, Technical Assistant to Robert Gilruth, to discuss a possible study contract on this mode. Purser referred Daniels to NASA Headquarters. Almost a year later, in June 1962, John N. Cord and Leonard M. Seale, two engineers from Bell Aerosystems, urged in a paper presented at an Institute of Aerospace Sciences meeting in Los Angeles that the United States adopt this technique for getting a man on the moon in a hurry. While he waited for NASA to find a way to bring him back, they said, the astronaut could perform valuable scientific work. Cord and Seale, in a classic understatement, acknowledged that this would be a very hazardous mission, but they argued that "it would be cheaper, faster, and perhaps the only way to beat Russia." There is no evidence that Apollo planners ever took this idea seriously.Today, of course, there is no space race. And the official reason for not going to Mars is that we're not ready yet—technically, financially, biologically, psychologically. But some of the excuses bear closer examination. Consider the "humans can't live for three years in space" problem. A one-way trip to Mars only takes six months. Many astronauts and cosmonauts have flown space missions longer than that, so the risk due to zero-g deconditioning seems surmountable already. True, the radiation hazard would be greater on a Mars voyage, but is that necessarily a show-stopper? An increase in lifetime cancer risk probably won't be the biggest -- or even the tenth biggest -- danger faced by the first Martian settlers. Here I'm reminded of Butch Cassidy's pep talk to the Sundance Kid: "Hell, the fall will probably kill you."
I don't mean to be cavalier about safety, or accuse anyone who doesn't sign up for a one-way trip to Mars of cowardice. But if settling Mars is the goal, what are we waiting for? If we're only interested in exploring other worlds, we can do that more safely (if more slowly) with robots. If we claim it's living on Mars that we really want, why not get started? Davies and Schulze-Makuch have pointed the way.