Mouse embryos sent into space did not survive. Chinese scientists say the finding is a stark warning for anyone dreaming of having babies beyond Earth.
A failed experiment aboard a cargo spacecraft
Researchers from the Chinese Academy of Sciences loaded 640 mouse embryos onto the Tianzhou-1 cargo spacecraft in 2017. The spacecraft orbited Earth for four days. When the embryos returned, none had developed into a normal fetus. Most had stopped growing at the two cell stage. Some showed severe structural damage.
The team published the results in a peer reviewed journal in 2024. The study was led by researchers at the Institute of Zoology in Beijing. They wanted to test whether mammalian embryos could survive the launch and the microgravity environment of space.
Why local scientists and space agencies took notice
China has ambitious plans for long duration human spaceflight, including a permanent space station and future missions to the Moon. If humans ever live in space for years at a time, reproduction becomes a real question. The study suggests that the earliest stages of development may be the most vulnerable.
The scientists found that microgravity disrupted the formation of the blastocyst, a structure that forms a few days after fertilization. Without a healthy blastocyst, a pregnancy cannot proceed. The embryos also showed changes in gene expression related to cell division and metabolism.
A silver lining for future research
The experiment was not a total loss. The researchers noted that some embryos did reach the blastocyst stage, though none developed further. This suggests that with additional protection or artificial gravity, mammalian embryos might have a chance. The team is now planning follow up experiments on China's Tiangong space station to test whether a centrifuge that simulates gravity could improve outcomes.
For now, the message is clear. Space is not a friendly place for new life. But the work is just beginning.
