Spirit and Opportunity find evidence of ancient water on Mars
Twin rovers designed for 90 days operate for years and reshape what scientists know about Mars's past
Quick facts
- Agency
- NASA / JPL
- Spirit landing
- 3 January 2004, Gusev Crater
- Opportunity landing
- 24 January 2004, Meridiani Planum
- Planned vs actual mission
- 90 days planned; years actual
What happened
NASA's twin Mars Exploration Rovers landed three weeks apart in January 2004: Spirit on 3 January in Gusev Crater, chosen because geologists suspected it once held a lake, and Opportunity on 24 January on the opposite side of the planet at Meridiani Planum, an area with mineral signs of a wet history. Designed to operate for just 90 days, both rovers vastly outlasted their planned missions. Soon after landing, Opportunity found small spherical mineral grains nicknamed 'blueberries,' rich in hematite, that had formed in acidic water. Spirit later found evidence of ancient hot springs that could have supported microbial life. Spirit's mission ended in 2010 after it became stuck in soft soil; Opportunity kept operating until a planet-wide dust storm cut off its solar power in June 2018, having traveled nearly 30 miles over almost 15 years.
Why it matters
Spirit and Opportunity together produced the first direct, rover-level evidence that Mars once hosted multiple kinds of watery environments, fresh water, hot springs, acidic pools, transforming Mars science from an orbital-imagery guessing game into ground-truthed geology and setting up the search for organic chemistry that later rovers would pursue.
How we know
NASA's own retrospective on the rovers' twentieth anniversary documents the landing dates, sites, and mission durations from mission records; the Smithsonian's National Air and Space Museum overview of Mars rovers independently corroborates the blueberries discovery and Spirit's search for ancient hot springs.
Sources
- NASA. 20 Years After Landing: How NASA's Twin Rovers Changed Mars Science · Primary source (author-declared)nasa.gov · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
- Smithsonian National Air and Space Museum. Exploring the Red Planet with Robots · Reputable sourceairandspace.si.edu · The domain "airandspace.si.edu" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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