NASA celebrated the precision landing of the rover on Mars and marvelled over the mission's first photographs Monday — grainy, black-and-white images of Martian gravel, a mountain at sunset and, most exciting of all, the spacecraft's white-knuckle plunge through the red planet's atmosphere.
Curiosity, a roving laboratory the size of a compact car, landed right on target late Sunday night after an eight-month, 556-million-kilometre journey.
Cheers and applause echoed through NASA's Jet Propulsion Laboratory, and engineers hugged, high-fived and thrust their fists in the air after signals from space indicated the vehicle had survived the harrowing descent through the red planet's pinkish atmosphere.
JPL director Charles Elachi likened the team to Olympic athletes: "This team came back with the gold."
"Everybody in the morning should be sticking their chests out and saying, 'That's my rover on Mars,"' NASA administrator Charles Bolden told NASA TV.
Minutes after the landing signal reached Earth at 10:32 p.m. PT (1:32 a.m. ET), Curiosity beamed back the first black-and-white pictures from inside the Gale Crater showing its wheel and its shadow, cast by the afternoon sun.
"We landed in a nice flat spot — beautiful, really beautiful," said engineer Adam Steltzner, who led the team that devised the tricky landing routine.
Extraordinary efforts were needed for the landing because the rover weighs about one tonne, and the thin Martian atmosphere offers little friction to slow a spacecraft down. Curiosity had to decelerate to a dead stop from 20,900 km/h in seven minutes, unfurling a parachute, then firing rockets to brake. In a Hollywood-style finish, cables delicately lowered it to the ground at three km/h.
It was NASA's seventh landing on Earth's neighbour; many other attempts by the U.S. and other countries to zip past, circle or set down on Mars have gone awry.
The arrival was an engineering tour de force, debuting never-before-tried acrobatics packed into "seven minutes of terror" as Curiosity sliced through the Martian atmosphere at 20,900 km/h.
Cables delicately lowered the rover to the ground at a snail-paced 3.2 km/h. A video camera was set to capture the most dramatic moments — which would give Earthlings their first glimpse of a touchdown on another world.
Gilles Leclerc, director-general of space exploration at the Canadian Space Agency, said workers there were celebrating as well, having spent years working on a device aboard Curiosity that will help look for signs of life.
"Well, we're Canadians, eh? So it was less enthusiastic, but I would say it was as emotional as it was in the U.S. But there were cheers indeed and it was again a great moment."
Still, he said from Longueuil, Que., there were some tense moments.
"The seven minutes of terror that we had been told to expect turned into a triumph in the end because it was a very daring landing technique and it was successful … so we were all very ecstatic."
The extraterrestrial feat injected a much-needed boost to NASA, which is debating whether it can afford another robotic Mars landing this decade. At a budget-busting $2.5 billion US, Curiosity is the priciest gamble yet, which scientists hope will pay off with a bonanza of discoveries and pave the way for astronaut landings.
U.S. President Barack Obama lauded the landing in a statement, calling it "an unprecedented feat of technology that will stand as a point of national pride far into the future."
Over the next two years, Curiosity will drive over to a mountain rising from the crater floor, poke into rocks and scoop up rust-tinted soil to see if the region ever had the right environment for microscopic organisms to thrive. It's the latest chapter in the long-running quest to find out whether primitive life arose early in the planet's history.
The voyage to Mars took more than eight months and spanned about 566 million kilometres. The trickiest part of the journey? The landing. Because Curiosity weighs nearly a ton, engineers drummed up a new and more controlled way to set the rover down. The last Mars rovers, twins Spirit and Opportunity, were cocooned in air bags and bounced to a stop in 2004.
Curiosity relied on a series of braking tricks, similar to those used by the space shuttle, a heat shield and a supersonic parachute to slow down as it punched through the atmosphere.
And in a new twist, engineers came up with a way to lower the rover by cable from a hovering rocket-powered backpack. At touchdown, the cords cut and the rocket stage crashed a distance away.
Curiosity packed with tools
The nuclear-powered Curiosity, the size of a small car, is packed with scientific tools, cameras and a weather station. It sports a robotic arm with a power drill, a laser that can zap distant rocks, a chemistry lab to sniff for the chemical building blocks of life and a detector to measure dangerous radiation on the surface.
It also tracked radiation levels during the journey to help NASA better understand the risks astronauts could face on a future manned trip.
Over the next several days, Curiosity was expected to send back the first colour pictures. After several weeks of health checkups, the six-wheel rover could take its first short drive and flex its robotic arm.
The landing site near Mars' equator was picked because there are signs of past water everywhere, meeting one of the requirements for life as we know it. Inside Gale Crater is a five-kilometre-high mountain, and images from space show the base appears rich in minerals that formed in the presence of water.
Previous trips to Mars have uncovered ice near the Martian north pole and evidence that water once flowed when the planet was wetter and toastier unlike today's harsh, frigid desert environment.
Curiosity's goal: to scour for basic ingredients essential for life including carbon, nitrogen, phosphorous, sulfur and oxygen. It's not equipped to search for living or fossil microorganisms. To get a definitive answer, a future mission needs to fly Martian rocks and soil back to Earth to be examined by powerful laboratories.
The mission comes as NASA retools its Mars exploration strategy. Faced with tough economic times, the space agency pulled out of partnership with the European Space Agency to land a rock-collecting rover in 2018. The Europeans have since teamed with the Russians as NASA decides on a new roadmap.
Despite Mars' reputation as a spacecraft graveyard, humans continue their love affair with the planet, lobbing spacecraft in search of clues about its early history. Out of more than three dozen attempts — flybys, orbiters and landings — by the U.S., Soviet Union, Europe and Japan since the 1960s, more than half have ended disastrously.
One NASA rover that defied expectations is Opportunity, which is still busy wheeling around the rim of a crater in the Martian southern hemisphere eight years later.