China’s Shenzhou-20 emergency reveal: cracks in the viewport reshape return plans

Chinese taikonauts aboard Shenzhou-20 discovered cracks in their return capsule’s viewport—likely from space debris—one day before planned reentry. Ground teams swapped to the backup Shenzhou-21 for landing while racing to prepare an uncrewed Shenzhou-22 and a porthole-repair capability. The 270‑day mission was completed safely using the replacement craft, marking China’s first spaceflight emergency and underscoring the importance of rapid rescue and contingency planning.