Gravity’s Rebound: Spine and Sole Pain After Long Space Missions

Returning astronauts often feel burning sole pain and lower-back ache within days of landing as swollen intervertebral discs in microgravity are suddenly compressed by Earth's gravity; skin loses its Earth-hardening calluses and the vestibular system re-calibrates, making first steps unsteady. Pain typically peaks around days 2–4 as discs rehydrate and recompress while paraspinal muscles re-adjust. The risk of herniated discs is highest in the first year post-flight, especially in the cervical spine. Recovery follows a pattern: stand soon after splashdown but walk unsteadily for days, height returns to normal in about 10 days, and bone density recovery lags behind. Artemis missions and future Mars transits will face these challenges without on-site ground support, requiring careful postflight conditioning.