# Mars Kept Its Secrets for 3.5 Billion Years. The Plan to Bring Them Home Just Got Canceled.

- slug: mars-kept-its-secrets-for-35-billion-years-the-plan-to-bring-them-home-just-got-canceled
- date: 2026-04-22
- category: Space & Aerospace

NASA canceled the Mars sample return mission in January. Three months later, Curiosity confirmed the red planet still holds the best-preserved record of early solar system chemistry — 21 organic molecules, 3.5 billion years old, including seven types never detected there before.

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