NASA's Mars lander Curiosity has landed safely on Mars. After a 253-day voyage punctuated by a dramatic plunge through the Martian atmosphere, the nuclear-powered rover has reported to mission control that it is on the ground and systems are nominal. The landing occurred at 10:31 p.m. U.S. PDT (August 6, 05:31 GMT) plus or minus a minute. The landing site was near the base of Mount Sharp inside Gale Crater, 4.6 degrees south latitude, 137.4 degrees east longitude. This marks the beginning of a two-year mission to seek out places where life may have existed on Mars – or may yet exist today.

Curiosity is the most ambitious Mars landing mission to date. Launched by NASA atop an Atlas V rocket from Cape Canaveral Air Force Station, Florida on November 26, 2011, the US$2.5 billion mission is intended to study Gale Crater for past and present signs of habitable environments where life might have, or does exist.

At a current distance of 154 million miles (248 million km), the time it took for the signal confirming the lander's successful touchdown took 13.8 minutes to reach Flight Control. Because of this lag, the landing had to be done entirely under automatic control. This in itself was enough to instill a severe case of nerves in Mission Control members at NASA’s Jet Propulsion Laboratory in Pasadena, California.

When that automatic control had to operate while slamming into the Martian atmosphere at 13,200 mph (5,900 mps) with deceleration forces of up to 11 g’s, control an Entry vehicle with a revolutionary heat shield capable of flying like a lifting body, deploy a supersonic parachute at exactly the right moment, jettison the shield and aeroshell seconds later and then drop the Curiosity rover gently to the surface using a rocket powered sky crane, then it's understandable if those nerves became seriously jangled. The purpose of all of this was to bring Curiosity safely to the surface of Mars – and it worked.

Here's NASA's official update marking the historic landing:

"NASA's Curiosity rover has landed on Mars! Its descent-stage retrorockets fired, guiding it to the surface. Nylon cords lowered the rover to the ground in the 'sky crane' maneuver. When the spacecraft sensed touchdown, the connecting cords were severed, and the descent stage flew out of the way. The time of day at the landing site is mid-afternoon -- about 3 p.m. local Mars time at Gale Crater. The time at JPL's mission control is about 10:31 p.m. Aug. 5 PDT (early morning EDT)."

Curiosity is itself a record breaker, being the largest rover ever sent to the Red Planet. The size of a 4x4, it’s 9 feet, 10 inches (3.0 m) long, stands 7 feet (2.1 m) tall with its mast extended and weighs 1,982 pounds (899 kg). And if that isn’t enough, it is nuclear powered with a radioisotope thermoelectric generator cranking out 2,700 watts and lithium-ion batteries for backup.

Curiosity carries ten science experiments as part of its 165 pound (75 kg) c(MLS). Its equipment includes a mast with high-definition cameras, a robotic arm for collecting samples and a laser that is powerful enough to vaporize rock for spectrographic analysis. The MLS also has the most sophisticated laboratory ever sent to Mars to seek signs of water and analyze soil and rock samples.

Curiosity’s primary mission is scheduled to last one Martian year (98 weeks), during which it will roam around Gale Crater carrying out experiments and seeking areas where life may exist. Having survived the landing, it must now survive hard UV and other radiation, highly corrosive soil, dust storms far more violent than any on Earth and temperatures ranging from -130° F to 32° F (-90° C to 0° C). That’s a lot for any rover to go through, but if the careers of Curiosity’s predecessors such as Opportunity are any indicator, surviving the landing may be the scary prelude to a long, fruitful career.

Source: NASA