Mars mission probes how planet lost its water

NASA's latest Martian probe is nearing its destination, and once it's there the mission will start studying for the first time the planet's upper atmosphere, ionosphere, and interactions with the solar wind to determine why the once-watery Mars has evolved into a barren, frozen world.

If all goes as planned, MAVEN, for Mars Atmosphere and Volatile Evolution Mission, is scheduled to be inserted into an elliptical orbit on Sept. 21. Programme officials said this week that MAVEN's current trajectory "looks good" as they continue to run simulated orbital insertions that include plenty of "what-if" scenarios.

Once in orbit around Mars, at least one "precautionary manoeuvre" is planned in October before MAVEN's main science phase begins in early November. At the lowest point in its orbit, the 37.5-foot-wide orbiter will be 93 miles from the Martian surface.

NASA's Mars Maven will study the upper atmosphere of Mars using an ultraviolet spectrometer and a solar wind ion analyser. (Source: NASA)

MAVEN is the first probe dedicated to studying the Martian atmosphere and climate in an attempt to determine the fate of the planet's ancient supply of liquid water and thick atmosphere. Scientists think the Martian atmosphere has been gradually slipping away into space over the last 1 billion years. They hope to use MAVEN's array of instruments to find out how and why.

"The goal is to come up with a better understanding of what happened to the Martian atmosphere and how planetary atmospheres evolve over time," explained Jim Morrissey, MAVEN instruments systems manager at NASA's Goddard Spaceflight Center in Maryland.

MAVEN and the ongoing Curiosity rover mission are, among other things, trying to establish that Mars once harboured conditions suitable for life. Planetary scientists want to know why the Martian atmosphere and climate changed over time and how solar activity contributes to atmospheric loss.

MAVEN was launched from Cape Canaveral last November and is currently traveling at a speed of about 16 miles per second on a 10-month, 442-million-mile journey to the fourth planet in our solar system.

Instruments

One of MAVEN's eight instruments, a solar wind ion analyser, will measure the electrically charged particles in what's left of the Martian atmosphere to find out where it went and why. Most of the ions being measured will be within the solar winds. The ions interact with neutral gas particles in the thin upper Martian atmosphere, allowing them to resist the planet's gravitational pull.

Scientists suspect these interactions played a role in stripping the planet of its atmosphere, leaving behind a reddish desert landscape where liquid water once flowed. "Our goal is to find out what happened to the water," Morrissey said in a Sept. 10 interview.

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