Oman-found Martian meteorite returns to Mars as Perseverance's calibration standard

A dark rock found in Oman is SaU 008, a fragment of Mars, and today a slice of it sits on the Perseverance rover as a SHERLOC calibration target. The meteorite’s 300,000-year journey — Mars to Earth and back to Mars — provides a known reference to ground-truth Raman and fluorescence readings and helps monitor the instrument’s response over time, making it an ordinary yet essential tool rather than a mere keepsake.