Space mice come home and one female gives birth

Four mice flew on China's Shenzhou-21 for two weeks and returned in mid‑November; on 10 December one female gave birth. Scientists will monitor the pups for possible multi‑generational effects.

Four mice numbered 6, 98, 154 and 186 were launched to China’s space station on 31 October aboard Shenzhou‑21 and spent about two weeks in microgravity and space radiation before returning on 14 November. On 10 December one of the females gave birth to pups; researchers say the mother is nursing and the young are developing well. Mission details The mice lived under carefully controlled conditions in orbit: lights were kept on a 7 a.m.–7 p.m. cycle to mimic Earth’s circadian rhythm, food was nutritionally balanced and intentionally hard to allow normal tooth grinding, and directional airflow collected hair and waste. An AI monitoring system tracked movement, eating and sleep in real time. Operational challenges When the return schedule shifted unexpectedly, ground staff tested emergency rations from crew supplies — compressed biscuits, corn, hazelnuts and soy milk — and selected soy milk as the safest emergency option after verification on Earth. Water was supplied to the habitat through an external port during the extended stay. Scientific context and next steps Mice are often used as mammalian models because of genetic and physiological similarities to humans; if short missions in orbit altered reproductive ability, mice would likely show early signs. Wang Hongmei of the Chinese Academy of Sciences’ Institute of Zoology highlighted that the result — a female able to give birth after short‑term spaceflight — suggests no obvious damage to reproductive capacity from this mission. Researchers will continue to monitor the pups’ growth, look for physiological changes and test whether the offspring can reproduce normally to check for multi‑generational impacts. Suggestions It would be useful for researchers to continue longitudinal monitoring of the pups’ development and health, assess their reproductive capacity in later life, expand sample sizes and mission durations where feasible, and study possible radiation and microgravity effects across generations to better inform plans for long‑duration human space exploration.