AP Photo/NASA/JPL-Caltech
In this frame provided by NASA of a stop motion video taken during the NASA rover Mars landing, the heat shield falls away during Curiosity's descent to the surface of Mars on Sunday, Aug. 5, 2012.

The most elaborate, technically difficult and demanding dismount came not in the London Olympics but 352 million miles away in a vast Martian crater.

In a sequence NASA called "seven minutes of terror," the mobile science lab Curiosity decelerated from 13,000 mph to be gently deposited on the ground through an elaborated choreographed sequence involving a giant parachute, 79 separate detonations to jettison ballast, protective shields and the parachute itself. A "sky crane" with retro rockets then took over and with Curiosity safely in place, cut its tethers and flew off to crash a safe distance away.

It was the end of a journey that began last Nov. 26.

One slip-up and $2.5 billion would have been down the drain. Martian expeditions are no sure thing even when it's a fly-by with no landing involved. The Associated Press says of more than three dozens attempts since the 1960s more than half ended disastrously.

Thus the understandable reaction of engineer Allen Chen, the deputy leader of the rover's descent and landing: "I can't believe this. This is unbelievable."

Curiosity was not a tiny craft like the two rovers launched in 2004 with expected life spans of three months. (One of which, Opportunity, against all odds, is still trundling around the planet.) Curiosity is a nuclear-powered, six-wheel research vehicle the size of a small car, packed with scientific instruments, and with an Earth weight of a ton.

Curiosity went right to work and began transmitting photos back to Earth, the start of its two-year mission to learn as much about the Red Planet as possible, particularly looking for any evidence that Mars once supported life.

The successful landing was an important victory for NASA, which has seen the end of the space shuttle program and its most ambitious projects canceled for budgetary reasons or by changes in administrations.

President Barack Obama, who has been accused by Republicans of being insufficiently ardent about "American exceptionalism," called the landing an "unprecedented feat of technology that will stand as a point of national pride far into the future."

Jet Propulsion Laboratory Director Charles Elachi put the feat in a more contemporary context. "This team came back with the gold," he said. Indeed they did and sincere congratulations to all.