But that hasn’t stopped the Curiosity rover from running around saying “This spot would have been habitable” and “That spot definitely has water.” And it hasn’t stopped astronomer Nathalie Cabrol from searching for the ever-elusive “biosignatures”: evidence, like geological graffiti, that proclaims “LIFE WUZ HERE.”
But it isn’t as easy as finding a spray-painted tag. First of all, the life almost certainly isn’t alive anymore. And second of all, it probably hasn’t been alive for a long time. Around 3.5 billion years ago, Mars changed from being a relatively nice place into the frozen radiation-zapped desert it is today. It was never San Juan, but it does seem to have had a milder climate, water oceans, and a thick, protective atmosphere. If this young sub-Caribbean Mars was home to life, that life may have left its mark. The problem is that we aren’t totally sure what that mark might look like.
The collective space vision of all the world’s countries at the moment seems to be Mars, Mars, Mars. The U.S. has two operational rovers on the planet; a NASA probe called MAVEN and an Indian Mars orbiter will both arrive in Mars orbit later this month; and European, Chinese and additional NASA missions are in the works. Meanwhile Mars One is in the process of selecting candidates for the first-ever Martian colony, and NASA’s heavy launch vehicle is being developed specifically to launch human missions into deep space, with Mars as one of the prime potential destinations.
But is the Red Planet really the best target for a human colony, or should we look somewhere else? Should we pick a world closer to Earth, namely the moon? Or a world with a surface gravity close to Earth’s, namely Venus?
To explore this issue, let’s be clear about why we’d want an off-world colony in the first place. It’s not because it would be cool to have people on multiple worlds (although it would). It’s not because Earth is becoming overpopulated with humans (although it is). It’s because off-world colonies would improve the chances of human civilization surviving in the event of a planetary disaster on Earth. Examining things from this perspective, let’s consider what an off-world colony would need, and see how those requirements mesh with different locations.
There’s something rejuvenating about escaping civilization for the quiet isolation of unadulterated wilderness. But could you leave it all behind — forever? That’s the fate that awaits the men and women still in contention for a one-way ticket to the Red Planet.
Amy Shira Teitel is a freelance space writer whose work appears regularly on Discovery News Space and Motherboard among many others. She blogs, mainly about the history of spaceflight, at Vintage Space, and tweets at @astVintageSpace.
Last week, NASA announced its next planetary mission. In 2016 the agency is going back to the surface of Mars with a spacecraft called InSight. The mission’s selection irked some who were hoping to see approval for one of the other, more ambitious missions up for funding: either a hopping probe sent to a comet or a sailing probe sent to the methane seas of Saturn’s moon Titan. Others were irked by NASA’s ambiguity over the mission’s cost during the press announcement.
An artist’s rendition of InSight deploying its seismometer and heat-flow experiments on Mars.
InSight is part of NASA’s Discovery program, a series of low-cost missions each designed to answer one specific question. For InSight, that question is why Mars evolved into such a different terrestrial planet than the Earth, a mystery it will investigate by probing a few meters into the Martian surface. The agency says InSight’s selection was based on its low cost—currently capped at $425 million excluding launch costs—and relatively low risk. It has, in short, fewer known unknowns than the other proposals.
But while InSight costs less than half a billion itself, the total value of the mission by the time it launches will be closer to $2 billion. How can NASA get that much zoom for so few bucks? By harnessing technologies developed for and proven on previous missions. The research, development, and testing that has gone into every previous lander take a lot of guesswork out of this mission, helping it fly for (relatively) cheap.
Aside from the Moon, Mars is the only body in the solar system that NASA has landed on more than once. With every mission, the agency learns a little more, and by recycling the technology and methods that work, it’s able to limit expensive test programs. This has played no small part in NASA’s success on the Red Planet thus far. When it comes to the vital task of getting landers safely to the surface, NASA has been reusing the same method for decades. It has its roots way back in the Apollo days.