It’s official: Mouse embryos can grow in space. After launching a satellite containing over 6,000 pre-birth rodents and studying them under a high-resolution camera in zero gravity, China has proven it.

The question that remains is, why did they bother?

The reason is more ambitious than you might think. As with many of their projects, the Chinese government is thinking very long-term here. In their view, the success of these mouse embryos tells us about humankind’s future place—or places—in the universe.

“The human race may still have a long way to go before we can colonize the space [sic],” said Duan Enkui, the lead researcher in the experiment. “But before that, we have to figure out whether it is possible for us to survive and reproduce in the outer space environment like we do on Earth.”

At least for mice, we now know that’s possible. According to the Chinese Academy of Sciences, China’s space mice were able to progress from 2-cell structures into blastocysts within 72 hours, which is on par with their development on Earth.

Whether human embryos could have the same success remains to be seen. But China sees its experiment as bringing us one step closer to proving it’s possible, and therefore one step closer to humanity’s—or maybe just China’s—colonization of other planets. It’s one small skitter for a mouse, one giant leap for mankind.