BOULDER, Colo., Oct. 7 (UPI) -- A NASA mission to Mars will study how the sun has stolen the planet's atmosphere, condemning it to a cold and sterile existence, researchers say.
Mars once had a thicker atmosphere and was warm enough for liquid water to flow on the surface, scientists believe, but somehow that thick atmosphere got lost in space, a NASA release says.
The sun with its solar wind is the principal suspect.
All planets in our solar system are constantly blasted by the thin stream of electrically charged gas that continuously blows from the sun's surface into space. Earth's global magnetic field shields our atmosphere by diverting most of the solar wind around it.
"Mars can't protect itself from the solar wind because it no longer has a shield, the planet's global magnetic field is dead," said Bruce Jakosky of the University of Colorado, Boulder, principle investigator for NASA's MAVEN (Mars Atmosphere and Volatile Evolution Mission) probe.
Earlier Mars spacecraft missions such as NASA's Mars Global Surveyor and the European Space Agency's Mars Express spacecraft have caught glimpses of the phenomenon.
"Previous observations gave us 'proof of the crime' but only provided tantalizing hints at how the sun pulls it off -- the various ways Mars can lose its atmosphere to solar activity," said Joseph Grebowsky of NASA's Goddard Space Flight Center in Greenbelt, Md.
"MAVEN will examine all known ways the sun is currently swiping the Martian atmosphere, and may discover new ones as well," he said.
MAVEN is scheduled for launch between Nov. 18 and Dec. 7, 2013, NASA says.
