A year ago today the Curiosity rover’s wheels touched Martian soil after a daring descent via a rocket-powered sky crane. Even if you’ve already seen the video of the landing, watch it again. I can’t get over how much it looks like a scene from a sci-fi movie … but isn’t. And that’s the wonder of it.
Gale Crater, a 96-mile-wide (155 km) impact crater, was chosen as the landing site because it’s filled with layered sediments deposited by wind and water over the eons. Some of layers contain hardened clays from days when water flowed freely on the Red Planet. Nowadays the air’s so thin that if you filled a dog bowl with liquid water there it would immediately boil away to nothing.
Mission control put the robotic geologist to work right away taking pictures, scooping soil samples, and laser-zapping and drilling rocks. In September, Curiosity discovered ample evidence for water when it wheeled across a hardened river bed packed with pebbles tumbled by a stream billions of years ago. Later in March the robot spied white mineral veins deposited by water lining a rock face in on the rocky flats of Yellowknife Bay.
Like Goldilock’s porridge, the water was neither too salty nor too acidic but fresh enough to dip your cup in for a drink, according to Curiosity chief scientist John Grotzinger.
Curiosity sniffed out traces of other important life-energizing elements like carbon, sulfur, phosphorus, hydrogen, oxygen and nitrogen. It appears that the conditions found on the early Earth that led to the formation of life were also present on Mars at one time. Since life appears to be the greatest achievement ever realized by the hapless dust between the stars, nothing would please me more than to learn it’s inevitable when the conditions are right. But Curiosity wasn’t built to find microbes, the most likely life form on Mars if it ever came to be.
The mission’s main goal of determining whether Mars could have offered a friendly habitat for life in the past has been achieved. New horizons beckon. Curiosity is ambling toward the slopes of Mount Sharp five miles (8 km) away. Nine months to a year from now it will reach the mountain’s lower layers of sedimentary rock where Mars’ orbiters have found the signature of clay minerals. Clay form from water-eroded rock.
Curiosity will first investigate the clay-rich layers near the mountain’s base and then climb to a unique divide some 2,625 feet (800 m) up-slope where clay gives way less water-altered rock. Lower layers reflect earlier times; the higher up the robot climbs, the closer it will approach present-day Mars. Perhaps we’ll discover more clues on what caused the planet’s climate to radically change from wet to dry.
I shoot plenty of photos every day in my job as a newspaper photographer, but Curiosity has me beat by a mile, sending back more than 72,393 images as of August 6. Check out a selection HERE or drop by the raw image archive and have your fill. Oh, and enjoy another panorama shot - this one you can really dig into.
Apart from all the geology and photos, the rover also learned that astronauts on a year-plus round trip mission to Mars would exceed radiation exposure limits. Radiation danger comes from two main sources: galactic cosmic rays, particles accelerated to high speed by supernova explosions and other high-energy events outside the solar system, and speedy electrons and protons shot out by the sun during solar flares and coronal mass ejections. NASA’s considering ways to speed up the trip and devise more effective shielding.
Weather-wise, the rover has measured wind flows within Gale Crater, photographed clouds and experienced a wide range of temperatures. It hit 43 F (6 C) on the toastiest day and bottomed out at -132 F (-91 C). Click HERE for daily Mars weather details. By the way, the average high and low temperatures at Curiosity’s location have been 12 F (-11 C) and -106 F (-77 C).