MAVEN captures solar storm hitting Mars, prepares for comet flyby

NASA’s MAVEN mission has sent back its first look at a solar storm that hit the Martian atmosphere last month, delivering detailed images of the halos of hydrogen, oxygen and carbon surrounding the Red Planet and even mapping the ozone lying beneath these high atmospheric layers. And, technically, it hasn’t even started its science phase yet.

“Just this morning my administrative assistant told me that for the first time in months she’s hearing me whistling again as I walk down the corridor,” MAVEN principal investigator Bruce Jakosky, a planetary scientist at the University of Colorado, Boulder, said at a briefing. “This is going to really be an exciting mission.”

The spacecraft is still in its six-week commissioning phase while it checks its systems and adjusts its orbit. But the early findings are a promising start for the Mars Atmosphere and Volatile Evolution spacecraft, which entered orbit around the Red Planet on Sept. 21.

The mission – NASA’s first dedicated to studying the upper Martian atmosphere – will help answer some deceptively straightforward questions: If Mars once had an Earthlike atmosphere, how long did it last, and where did it all go?

Though Mars today is a dry planet with a thin atmosphere that’s roughly one-hundredth as thick as Earth’s, planetary scientists think the planet once had a thick protective layer of air that allowed water to remain liquid on the surface. An abundance of carbon dioxide, which is a greenhouse gas, would have helped to keep the atmosphere warm.

Liquid water is a key ingredient for life as we know it, and how long this protective atmosphere lasted on Mars could tell scientists how likely it is that microbial life ever emerged.

The three elements that make up water and carbon dioxide — hydrogen, oxygen and carbon — are of prime interest to the scientific team, and they break down and rise into the atmosphere over time. That’s why, soon after entering orbit and while it hovered around its highest point over Mars, the spacecraft used an ultraviolet spectrograph to take images of each of these elements escaping the planet. Hydrogen, which is the lightest element, rises most easily, and forms an enormous envelope around the planet that extends deep into space. Carbon and oxygen, slightly heavier elements, hug the planet’s outlines a little more closely.

The researchers also tracked the impact of a coronal mass ejection that the sun unleashed Sept. 26 and that hit Mars three days later. Solar particles and radiation probably played a major role in making that highest layer of atmosphere disappear, and MAVEN has a suite of instruments designed to measure these present-day interactions.

This prequel to MAVEN’s main science mission isn’t over – comet Siding Spring is set to fly by Mars on Sunday, and the particles it sheds could potentially interact with the upper atmosphere in fascinating ways. But how interesting the event is depends on how active the comet is, said Justin Deighan of the University of Colorado, Boulder, a member of MAVEN’s remote sensing team.

“Comets and cats have a lot in common – they both have tails and they do whatever they like,” said Deighan, paraphrasing Canadian comet-hunter David H. Levy. “So we can’t guarantee what kind of an impact you’re going to see this weekend. But if it’s cool, we’ll be making images like this to try to show what happened.”

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