On July 22, NASA officially announced that Curiosity will land at Gale Crater, where they hope to learn how Mars turned from a wet, potentially habitable planet into a dry, acidic wasteland. Mission managers selected the site over an ancient river-like delta in Eberswalde Crater, which may contain stronger traces of organic carbon.
“It’s like the layers in the Grand Canyon, a sequence of rocks laid out before you that traverse a lot of geologic history,” said planetary scientist John Mustard of Brown University, a 20-year veteran of Mars missions. “Layer by layer, Curiosity’s going climb from the bottom and up through Martian time.”
The $2.5 billion Curiosity rover, also called the Mars Science Laboratory, will follow up on years of orbital satellite imaging and surface investigation performed by smaller, solar-powered rovers.
The spacecraft is tentatively scheduled to launch Nov. 25 from Kennedy Space Center in Florida.
Following launch and a 48-million-mile interplanetary trip, Curiosity faces a punishing atmospheric entry, then an extremely complex landing sequence that rivals any previous Mars rover landing.
“This landing has a particularly intense fear factor to it,” Mustard said. “I talked to the engineers, and they’re most confident of this part of the mission. But I’m freaking out about it.”
The steps include heat-shield detachment, parachute deployment, use of landing radar, firing retro rockets and even dangling the 1-ton rover from tethers before a delivery pod clips them.
Decades of future Martian exploration may depend on Curiosity’s success or failure.
“The money spent on [Curiosity] was significant and there’s less money available for planetary science in the future. We’re talking a decade before a similar mission would be considered,” Mustard said. “Plus the landing system is meant to be the gold standard for future Mars exploration. If it fails, then something so critical to the future is gone.”
Assuming Curiosity lands in one piece, a bounty of scientific data awaits.
Unlike previous solar-powered rovers, the new robot has a steady nuclear fuel source that should allow it to explore for at least two years with the help of human controllers back on Earth. The 10-foot-long Curiosity rover (about the size of a compact car) is also far larger than earlier robots, which should help it avoid dangers like the sand traps that caught the Spirit Mars rover.
Curiosity also comes equipped with six cameras and more than 10 experimental instruments, including an organic chemical-sampling chamber, a water ice-detecting kit and mineral-analyzing tools.
A roughly 3.5-mile-high mound of layered sediment awaits Curiosity at Gale Crater, which is carved out of rock near the Martian equator.
Compared to Eberswalde Crater, Gale Crater is “not a one-trick pony,” said NASA planetary scientist Michael Meyer during a televised news briefing. The crater offers “attractive possibilities” for detecting organic carbon, Meyer said in a news release, although if organic carbon is found it’ll be hard to tell whether it came from lifeless asteroids or native organisms.
The mound contains sediments formed when Mars was wet and potentially habitable to life. More recent deposits will show when the planet turned acidic and ugly.
The stark transition occurred roughly 3.7 billion years ago, but exactly when and what caused the change isn’t certain. Curiosity could help find out, as could future but tentative missions to collect and return Martian soil samples.
“I think Gale offers the greatest opportunity to examine a fundamental planetary reorganization,” Mustard said. “It’s similar to finding out when Earth became oxygenated about 2.5 billion years ago by the rise of the biosphere. It’s a huge step forward from anything we’ve ever done before.”