Cassini Imaging Team/JPL/NASA
Ring It In: A trip toward Saturn is just one of many space missions scientists might choose to pursue in the coming years. Some researchers want to send a nuclear-powered boat to the methane lakes on one of Saturn's moons, Titan.
Vote for your top three space destinations.
Choosing which states to visit on your family's next road trip might seem tough, but imagine having to choose which planets you'd like to see. Planetary scientists gathered in Washington, D.C., this week to whittle down a list of list of potential robotic missions to other worlds.
The process, known as the "Decadal Review," will choose from 28 missions to planets, moons and even asteroids. "There were certainly some where I thought, 'Whoa, I didn't think of that one!'" says Steve Squyres, a researcher at Cornell University in Ithaca, N.Y., and the head of the study.
The field of planetary science is full of questions that need answers. Over the past decade, scientists have come to realize that many of our neighbors have complex lives and histories. Water may have once flowed on Mars, and present-day seas may be sloshing under the surface of Jupiter's moon Europa. And Jupiter is interesting in its own right: new theories suggest it moved billions of miles across the solar system before reaching its present-day orbit.
Closer studies of different parts of the solar system will help scientists learn how the planets work, and how the solar system itself formed. It will also provide important clues to where life has come from.
Road Trip, Anyone? While the Mars rover Opportunity has long outlived its planned life, scientists would like to send another lander to Mars. This craft, though, would send soil and rock samples back to Earth.
Road Trip, Anyone? While the Mars rover Opportunity has long outlived its planned life, scientists would like to send another lander to Mars. This craft, though, would send soil and rock samples back to Earth. JPL-Caltech/NASA
"The solar system is completely wide open," says Alan Stern, a scientist at the Southwest Research Institute in Boulder, Colo. "Almost anywhere we go, I'm sure we would learn a lot."
Deciding Where To Go
Arguably the most ambitious mission on the agenda would be a Mars lander that would send back soil and rock samples to earth. The size and complexity of such a mission, which would involve multiple spacecraft, rockets and landers, mean that it would cost billions. Another mission would travel to Jupiter's moon Europa to search for liquid oceans below the surface, which could be home to life. The Europa mission will attempt no landing there.
Picking one mission over another isn't easy. Who can say that a nuclear-powered boat paddling across the liquid methane lakes of Saturn's moon, Titan, is more or less exciting than a mission to see whether asteroids are home to the complex molecules needed for life?
Having researchers make the choice themselves is the best way to do it, says Jim Green, director of NASA's Planetary Science Division, which helped commission the study. "The whole planetary science community will get behind these things," Green says. "That will enable us to put the best foot forward."
Squyers, the Cornell astronomer, says the decisions will come down to more than just science. Money, readiness and the possibility of cooperation with international partners will all play a role in the panel's decisions.
Squyers says he's enjoyed learning about all the missions, but choices will have to be made. "The missions we are studying are just so damn cool," he says. "But are all those missions going to fly? Absolutely not."
A final list of road trip destinations is expected out this coming spring, just in time for NASA's 2013 budget.