We humans are a migratory bunch. We're always looking for new worlds to conquer. Sometimes, this impulse compels us to look beyond Earth's horizon to other worlds.
Four decades ago, the astronauts who leaped for joy in the moon's near-zero gravity believed they were in the vanguard of explorers destined to colonize the solar system in the latter part of the 20th century. It didn't quite work out that way.
Because of the change in National Aeronautics and Space Administration's approach to space exploration that emphasizes lower-cost unmanned probes, this nation won't attempt a manned orbital mission to Mars until 2030 or later, seven decades after the Apollo program ended.
Part of the reason is that the cost of getting humans to Mars and back is daunting. Maintaining an environment that would sustain and protect human life during the year-long round trip through space would account for 80 percent of the cost.
Two scientists writing in The Journal of Cosmology have proposed an intriguing, if cold-blooded, solution: Make the trip to the Red Planet one way. Dirk Schulze-Makuch and Paul Davies argue that sending older astronauts to establish Martian colonies would answer certain ethical objections arising from such a trip - such as the fact that heavy radiation exposure would ruin the reproductive capability of younger people.
Under this plan, the astronauts, all volunteers, would go into the mission knowing that they would die on Mars, perhaps within a few years of landing. The idea is that the vision of a self-sustaining colony on another planet would inspire those first colonizers to make the ultimate sacrifice.
Still, anyone comparing such trips to Mars to what the 15th-century European explorers did is overlooking one salient fact: The environment that the explorers encountered wasn't as alien as the surface of another planet. Even with constant resupplies from Earth, building a viable colony and learning to use Martian resources to generate food and oxygen would take decades. Many mistakes, some of them fatal, would be made.
Ultimately, asking a handful of older volunteers to risk their lives to establish human colonies on a dead, radiation-drenched world is a foolish gambit. It's unconscionable to strand humans millions of miles from home, even for the purpose of advancement in science.
Life is too precious and space exploration too grand to be done on the cheap. The United States should either commit to doing it right or not do it at all.