Red Planet Express: Mars spacecraft traces a watery tale
By Ron Cowen
A Mars-orbiting spacecraft is providing new details about when and where liquid water, an essential ingredient for life, existed on the planet. The craft’s instruments have detected a long-sought group of ancient, water-bearing compounds on Mars and have provided the first peek beneath the Red Planet’s surface.
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Over the past 3 decades, spacecraft and rovers have gathered compelling evidence that liquid water once existed in abundance on Mars. These data include images of channel networks gouged in the planet’s surface (SN: 5/28/05, p. 344: Roving on the Red Planet). But one hallmark of an aqueous era—surface minerals altered by water—remained elusive.