Curiosity is NASA's seventh landing on Mars ; 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 as Curiosity sliced through the Martian atmosphere at 13,000 mph.
The descent into Mars' atmosphere was billed as 'seven minutes of terror'. In a Hollywood-style finish, cables delicately lowered the rover to the ground at a snail-paced 2 mph. A video camera captured the most dramatic moments, and gave earthlings their first glimpse of a touchdown on another world.
"Touchdown confirmed....We are wheels down on Mars. Oh, my God." said an engineer in mission control as chorus of cheers and applause echoed through the NASA Jet Propulsion Laboratory after the most high-tech interplanetary rover ever built sent a signal to Earth.
The Mars rover has already sent its first low-resolution images - showing the its wheel and shadow, on the Red Planet's surface. High resolution colour images are expected in the next 48 hours.
At a budget-busting $2.5 billion, Curiosity is the priciest gamble yet, which scientists hope will pay off with a bonanza of discoveries. 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 352 million miles.
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. 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.
Curiosity's mission: 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 aims to study the Gale Crater, a 96-mile wide crater that contains a three-mile high mountain, shaped like a broad mound so the six-wheeled rover can climb at least halfway up the site. The vehicle is designed to function for 98 Earth weeks, or about one Martian year.
Mars is called the red planet because the landscape is stained rusty-red by the iron-rich dust. Its gravity is only 38 per cent that of Earth. So if you weigh 68 kgs on Earth, you would weigh 25 kgs on Mars.
Mars' temperatures can range from 80 degrees at its equator to -199 degrees at its poles. Mars' atmosphere is mostly carbon dioxide with traces of nitrogen and argon. Earth's atmosphere is a mixture of nitrogen, oxygen and other gases.
(With inputs from Agencies)