Ancient sextants could guide astronauts home if tech fails

NASA is reviving a 300-year-old sextant as a back-up navigation method for deep-space missions. Tests on the International Space Station showed hand-held sextants can help astronauts determine their position if communications or high-tech systems fail, a capability that could be crucial for Artemis and future Mars trips. On the Orion spacecraft, a high-tech optical navigation system already serves as a backup, but the sextant remains a last-resort option and highlights how ancient star-sighting techniques still underpin modern space navigation.