Nasa’s Maven spacecraft has arrived at Mars after a 442 million-mile flight through space that began a year ago.
After arriving at the Red Planet, Maven fired its main engines for about 33 minutes to slow down enough to “capture” into Mars’ orbit.
Flight controllers managing the $671m mission will spend six weeks checking the robotic explorer’s instruments before it begins observations of the red planet’s atmosphere.
The mission’s goal is to explore the planet’s upper atmosphere, ionosphere, and interactions with the Sun and solar wind.
Maven – the name is short for Martian Atmosphere and Volatile Evolution – will also explore the planet’s interactions with the Sun.
Scientists believe Mars’ atmosphere could hold clues as to how the planet went from being warm and wet billions of years ago to cold and dry today.
Early Mars could have harboured microbial life, researchers believe.
“This is such an incredible night,” said John Grunsfeld , Nasa’s chief for science missions.
Nasa launched Maven last November from Cape Canaveral , the 10th US mission sent to orbit the Red Planet.
Three earlier ones failed, and until the official word came of success late Sunday night, the entire team was on edge.
“I don’t have any fingernails any more, but we’ve made it,” said Colleen Hartman , deputy director for science at Goddard Space Flight Center in Greenbelt, Maryland . “It’s incredible.”
Maven joins three spacecraft already circling Mars, two American and one European.
India’s first interplanetary probe, Mangalyaan, will reach Mars in two days and also aim for orbit.
Maven will spend at least a year collecting data from Mars and its orbit will dip as low as 78 miles above the Martian surface as its eight instruments make measurements.
All these robotic scouts are paving the way for the human explorers that Nasa hopes to send in the 2030s.
Maven will have a rare brush with a comet next month.
The nucleus of newly discovered Comet Siding Spring will pass 82,000 miles (131,960 km) from Mars on October 19 .
The risk of comet dust damaging Maven is low, officials said, and the spacecraft should be able to observe Siding Spring as a science bonus.