Planetary geologists are gathering this week to start planning for the next robotic mission to Mars. It's supposed to be identical to Curiosity, but it'll be joined by a launch vehicle capable of sending samples back to Earth. But given what we now know about Mars, is this really necessary?

NASA hopes to have the next iteration of the rover on the Red Planet by 2020. Until that time there's still lots to figure out, including possible landing sites. Proposals include Mawrth Vallis (best name ever, an ancient valley strewn with minerals formed in water) and several ancient, now-dry lakes and deltas where water once flowed (including Eberswalde Crater).

The space agency also wants the new rover to do more than just collect and analyze samples. Nature News reports:


Scientists have talked for decades about getting their hands on Martian rocks to look for signs of past life. They have studied meteorites that originated on Mars, but no space agency has yet been able to bring back samples directly, in part because of the cost and in part because of technical failures.

NASA's plan for bringing back Martian samples would involve a succession of missions over many years...Step one would need a rover to collect and store roughly 30 narrow cylinders of rock and soil, either on board or on the ground. In step two, an unmanned rocket would fly to Mars and deploy another rover to fetch the samples and then blast them into orbit. Step three would be to capture that orbiting package and fly it back to Earth.

Being able to look at a chunk of rock from a particular location and understand its context would be a crucial step forward, says John Mustard, a planetary geologist at Brown University in Providence, Rhode Island. "If samples were returned, the science that could come out of that would be equivalent to when the Apollo samples came back from the Moon," he says. "It changes everything."

Any proposed location, therefore, will have to be suitable for the ascent vehicle.

I'm not so sure I'm happy about this. Sure, there's some science to be had, but it's becoming increasingly obvious that Mars is a cold, dead planet with absolutely nothing of interest on the surface. It's kind of upsetting to hear, in the words of planetary scientist Philip Christensen, that "the next 20 years of Mars exploration [will hinge] on where this rover goes." Seems like a rather limited strategy for the next two decades.


At the same time, Europa and Enceladus host subsurface oceans that may be more suitable to life. I'd rather see NASA devote its time and resources to these possibilities instead.

Image: NASA/Nature News.