Nasa's Mars rover Curiosity has landed safely after a two-year quest for signs that the Red Planet once hosted key ingredients for life.
Mission controllers burst into applause and cheered in relief as they received signals confirming that the rover had survived its perilous descent and arrived within its target zone at the bottom of a vast, ancient crater.
The robotic lab sailed through space for more than eight months, covering 352 million miles, before piercing the Martian atmosphere at 13,000 miles per hour – 17 times the speed of sound – before starting its descent.
Moments after landing, Curiosity beamed back its first three images from the Martian surface, one of them showing a wheel of the vehicle and the rover's shadow cast on the rocky terrain.
"I can't believe this. This is unbelievable," enthused Allen Chen, the deputy lead of the rover's entry, descent and landing team at the Jet Propulsion Laboratory near Los Angeles.
The craft's descent through the planet's thin atmosphere, a feat described as the most elaborate and risky achievement in the annals of robotic spaceflight, turned out to be short-lived cliffhanger, much to Nasa's relief.
Curiosity, encased in a protective capsule-like shell, used a brand new automated flight entry system to sharply reduce its speed before landing.
Then it rode a giant supersonic parachute, a jet-powered backpack and a never-before-used "sky crane" to touch down inside a vast impact basin named Gale Crater, located near the planet's equator in its southern hemisphere.
Nasa put the official landing time of Curiosity, the first fully fledged mobile science laboratory sent to a distant world, at 10:32pm Pacific time (0530 GMT).
Curiosity will spend two years exploring Gale Crater and an unusual three-mile-high mountain consisting of what appears to be sediments rising from the crater's floor.
The purpose of the $2.5bn mission is to look for evidence that Mars – the planet most similar to Earth – may have once harboured the basic building blocks necessary for microbial life to evolve.
It represents Nasa's first astrobiology mission since the 1970s-era Viking probes.
The landing marks a major milestone for a US space agency beset by budget cuts and the recent loss of its 30-year-old space shuttle programme.
"It's an enormous step forward in planetary exploration. Nobody has ever done anything like this," said John Holdren, the top science advisor to President Barack Obama, who was visiting JPL for the event. "It was an incredible performance."
The exact condition of the rover upon arrival was not immediately clear.
Nasa plans to put the rover and its laboratory gear through several weeks of engineering checks before starting its two-year surface mission in earnest.
The rover, launched in November from Cape Canaveral, Florida, comes equipped with an array of sophisticated instruments capable of analysing samples of soil, rocks and atmosphere on the spot and beaming results back to Earth.
One is a laser gun that can target a rock from 23ft away to create a spark whose spectral image is analysed by a special telescope to discern the mineral's chemical composition.