# Mars Kept Its Secrets for 3.5 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. ---