] Now that NASA's Opportunity rover has established a
] locale on Mars where rocks were once drenched in water,
] it is in a race against time and battery life to learn
] how widespread and deep the water was.
]
] Was there a giant sea, or did less conspicuous
] groundwater percolate locally through the subsurface of
] Meridiani Planum?
]

How Much Water on Mars? Rover Road Trip Seeks Answers