The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, scheduled to launch in late 2013, will orbit Mars and is devoted to understanding the Red Planet's upper atmosphere. It will help determine what caused the Martian atmosphere -- and water -- to be lost to space, making the climate increasingly inhospitable for life.
"Both MAVEN and Curiosity/SAM will determine the history of the Martian climate and atmosphere using multiple approaches," said MAVEN Principal Investigator Bruce Jakosky of the University of Colorado's Laboratory for Atmospheric and Space Physics. "Measurements of isotope ratios are an approach shared by both missions."
Isotopes are heavier versions of an element. For example, deuterium is a heavy version of hydrogen. Normally, two atoms of hydrogen join to an oxygen atom to make a water molecule, but sometimes the heavy (and rare) deuterium takes a hydrogen atom's place.
When water gets lofted into Mars' upper atmosphere, solar radiation can break it apart into hydrogen (or deuterium) and oxygen. Hydrogen escapes faster because it is lighter than deuterium. Since the lighter version escapes more often, over time, the Martian atmosphere has less and less hydrogen compared to the amount of deuterium remaining. The Martian atmosphere therefore becomes richer and richer in deuterium.
The MAVEN team will measure the amount of deuterium compared to the amount of hydrogen in Mars' upper atmosphere, which is the planet's present-day deuterium to hydrogen (D/H) ratio. They will compare it to the ratio Mars had when it was young -- the early D/H ratio. (The ear
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NASA/Goddard Space Flight Center