MAVEN’s mysteries: An inside look at NASA’s next Mars mission NBC News

NASA’s MAVEN orbiter is designed to follow up on a huge question surrounding past findings about Mars: If the Red Planet was once far more hospitable to life, what happened?
“What I’m most looking for is clarity,” the University of Colorado’s Dave Brain, a co-investigator for the $670 million mission, told NBC News. “We’re very certain that Mars has undergone some big change over the last several billion years.”
Part of that big change had to do with Mars’ atmosphere: Past studies have suggested that the carbon dioxide atmosphere was once thicker and more Earthlike, which would have kept the planet warmer and wetter. Now the atmospheric density is just 1 percent of Earth’s, offering little protection from the sun’s deadly ultraviolet blast. Where did the air go?
“There are only two answers to that question: You can go down, or you can go up,” Brain said.