Orbiting MAVEN Mission Set to Trace A Planet's History in Thin Martian Air

摘要

Eons ago, planetary scientists believe, Mars was blanketed by a thick atmosphere that sheltered a surface awash with water-conditions that could have allowed life to emerge and thrive. Today, that atmosphere is thin and depleted, and the martian surface is a cold, barren desert. What caused this remarkable transformation? If all goes well, a NASA spacecraft to be launched later this month will help answer that question. The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission will fly through the outer fringes of Mars's atmosphere, measuring gases and monitoring conditions with eight instruments. The measurements should help researchers figure out how, over billions of years, the ceaseless wind of particles from the sun combined with asteroid impacts and Mars's own surface chemistry to gradually deplete its atmosphere of water vapor and other gases. MAVEN is ultimately "about the habitability of Mars," says Bruce Jakosky, the mission's principal investigator and a geologist at the University of Colorado, Boulder. "If you are trying to understand the potential for life on Mars, you have to understand its climate history."