Nasa's Maven probe to study why Mars atmosphere changed over time
Nasa's newest Mars mission hopes to find out why the Martian atmosphere changed over time
Associated Press in Cape Canaveral, US
Nasa hopes its newest Mars spacecraft lives up to its know-it-all name.
The robotic explorer, called Maven, is due to blast off today on a 10-month journey to the red planet. There, it will orbit Mars and study the atmosphere to try to understand how the planet morphed from warm and wet to cold and dry.
"A maven is a trusted expert," said Nasa's space science chief, John Grunsfeld. Maven will help scientists "build a story of the Mars atmosphere and help future human explorers who journey to Mars", he added. The US$671 million mission is Nasa's 21st crack at earth's most enticing neighbour, coming on the heels of the Curiosity rover, still going strong a year after its grand Martian arrival.
When Maven reaches Mars next September, it will join three functioning spacecraft, two US and one European. An Indian orbiter also will be arriving at about the same time.
Maven will be the 10th orbiter to be launched to Mars by Nasa; three have failed, testimony to the difficulty of the task.
"No other planet, other than perhaps earth, has held the attention of people around the world [like] Mars," Grunsfeld said.
Early Mars had an atmosphere thick enough to hold water and moist clouds, said chief investigator Bruce Jakosky of the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder.
Indeed, water flowed once upon a time on Mars, and microbial life might have existed.
"But somehow that atmosphere changed over time to the cold, dry environment that we see today," Jakosky said. "What we don't know is what the driver of that change has been."
Maven - short for Mars Atmosphere and Volatile Evolution, with a capital N in EvolutioN - is the first spacecraft devoted entirely to studying Mars' upper atmosphere. India's orbiter will also study the atmosphere but go a step further, seeking out methane, a possible indicator of life.
Maven holds eight scientific instruments to measure the upper atmosphere for an entire earth year, half a Martian year. The boxy, solar-winged craft, as long as a school bus and weighing 2,450kg, will dip as low as 125 kilometres above the surface for atmospheric sampling, and its orbit will stretch as high as 6,218 kilometres.