Aging but still on the go, climbing in and around craters, tapping into the mysteries of strangely cracked rocks, the two roving vehicles Spirit and Opportunity have explored Mars.
SOURCE: NYTIMES
Still Exploring After Martian Winter, Rovers Send Back More Signs of Water
By JOHN NOBLE WILFORD
Published: October 8, 2004
Aging but still on the go, climbing in and around craters, tapping into the mysteries of strangely cracked rocks, the two roving vehicles Spirit and Opportunity have explored Mars about three times as long as originally scheduled and keep finding evidence of past liquid water shaping the now arid surface.
Mission officials reported yesterday that the rovers, which landed on Mars in January, have emerged from the planet's winter and resumed full operations. Even Spirit, suffering steering troubles with two of its six wheels, was able to climb higher into the hills inside a vast crater.
In a NASA teleconference with reporters, scientists said that in addition to evidence of water-altered bedrock the rover Opportunity had come across numerous flat rocks covered in cracks that form patterns of interconnected polygons. Or to be more down-to-earth, the rocks appeared to be fractured like dried mud.
The scientists showed pictures of the fractured rocks and suggested that they were possible evidence of watery episodes even after the main contours of the surface were formed, events that are also thought to have been associated with the presence of liquid water.
"When we saw these polygonal crack patterns, right away we thought of a secondary water event significantly later than the episode that created the rocks," said Dr. John Grotzinger, a geologist at the Massachusetts Institute of Technology who is on the rover science team.
At some point, Dr. Grotzinger explained, the rocks may have been...
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