Photos: Welcome to Mars
Reuters – NASA scientists hailed the Mars rover Curiosity's flawless descent and landing as a "miracle of engineering" on Monday as they scanned early images of an ancient crater that may hold clues about whether life took hold on Earth's planetary cousin.
The one-ton, six-wheeled laboratory nailed an intricate and risky touchdown late on Sunday, much to the relief and joy of scientists and engineers eager to conduct NASA's first astrobiology mission since the 1970s Viking probes.
Below: Curiosity rover
"We trained ourselves for eight years to think the worst all the time," Curiosity lead engineer Miguel San Martin said. "You can never turn that off."
NASA engineers said the feat stands as the most challenging and elaborate achievement in the history of robotic spaceflight, and opens the door to a new era in planetary exploration.
Encased in a capsule-like protective shell, the nuclear-powered rover capped an eight-month voyage as it streaked into the thin Martian atmosphere at 13,200 miles per hour (21,243 kilometers per hour), 17 times the speed of sound.
Plunging through the top of the atmosphere at an angle producing aerodynamic lift, the capsule's "guided entry" system used jet thrusters to steer the craft as it fell, making small course corrections and burning off most of its downward speed.
Closer to the ground, the vessel was slowed further by a giant, supersonic parachute before a jet backpack and flying "sky crane" took over to deliver Curiosity the last mile to the surface.
The rover, about the size of a small sports car, came to rest as planned at the bottom of a vast impact bowl called Gale Crater, and near a towering mound of layered rock called Mount Sharp, which rises from the floor of the basin.
A trio of orbiting satellites monitored what NASA had billed as the "seven minutes of terror," but the anxiety proved to be unfounded.
From an orbital perch 211 miles (340 km) away, NASA's sharp-eyed Mars Reconnaissance Orbiter snapped a stunning and serene picture of Curiosity gracefully riding beneath its massive parachute en route to Gale Crater, located near the planet's equator in its southern hemisphere.
Seven minutes after landing, the rover transmitted a picture, relayed by another Mars orbiter called Odyssey, showing one of Curiosity's wheels on the planet's gravel-strewn surface.
"When you see a picture of the surface of the planet with the spacecraft on it, that is the miracle of engineering," lead scientist John Grotzinger told reporters on Monday.
With the late-afternoon sun slipping behind the crater's rim, Curiosity relayed six more sample pictures and the results of initial health checks of some of its 10 scientific instruments before shutting down for the Martian night.
Additional photos taken by Curiosity were relayed hours later, including a batch of 200-plus images snapped at nearly four fames per second by the craft's bottom-mounted camera as it was lowered to the ground by parachute, rocket pack and sky crane. They were assembled by NASA into a rough-cut clip of moving footage showing the rover's descent from its own perspective, starting from the ejection of its heat shield.
One picture showing Mount Sharp in the background revealed that Curiosity landed virtually face-to-face with the mountain, with no obstacles between the two. A separate photo shot in the opposite direction shows the northwestern rim of the crater.
Scientists believe Mount Sharp may have formed from the remains of sediment that once completely filled the basin, offering a potentially valuable geologic record of the history of Mars, the planet most similar to Earth.
It may be months, however, before Curiosity heads over to Mount Sharp.
Heat shield falls away during Curiosity's descent on Mars
The image belows shows changes in the target landing area for Curiosity, the rover of NASA's Mars Science Laboratory project. The larger ellipse was the target area prior to early June 2012, when the project revised it to the smaller ellipse centered nearer to the foot of Mount Sharp, inside Gale Crater.