CAPE CANAVERAL, Fla. —
Scientists theorize that some of the early atmospheric water and carbon dioxide went down into the crust of the Martian surface — there is evidence of carbonate minerals on Mars. Gases also may have gone up and become lost to space, stripped away by the sun, molecule by molecule, Jakosky said.
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 as hefty as a 5,400-pound SUV — will dip as low as 78 miles above the surface for atmospheric sampling, and its orbit will stretch as high as 3,864 miles.
Understanding the makeup and dynamics of Mars’ present atmosphere will help guide humans more safely to the planet’s surface, especially if the ship takes advantage of the atmosphere for braking, Jakosky said. NASA targets the 2030s for the first manned expedition.
The spacecraft also holds an antenna and radio to serve as a communications relay for NASA’s two active Martian rovers, Curiosity and Opportunity, as well as the next pair of landers to be launched in 2016 and 2020.
Maven is considered so important that launch preparations were allowed to resume a couple of days after the start of the 16-day government shutdown. Maven has one month to launch; Earth and Mars line up just so, just every 26 months. So if Maven isn’t flying by mid to late December, the spacecraft will be grounded until the beginning of 2016.
The red planet is a notoriously tricky target. The world’s overall success rate since the 1960s for a Mars mission is less than 50-50.
NASA has attempted the most, 20 launches so far, and has the best success rate: 70 percent. Russia, in second place with 18 Mars launches, has a dismal 14 percent success rate. China collaborated on one of the Russian flops. Europe and Japan have attempted one Martian mission apiece; the European Mars Express has had mixed results, while the Japanese effort fizzled.