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Space-Grown Mouse Embryos Are a Step Toward Human Colonization

Chinese scientists report embryos developing from two-cell to blastocyst stage while onboard satellite SJ-10.
Image of the embryos having developed to the blastocyst stage 80 hours after launch. Image: Enkui Duan

Chinese scientists are creeping a tiny bit closer to the future dream of humans colonizing and reproducing in space.

They've succeeded, reports the Chinese Academy of Sciences, in developing early-stage mouse embryos aboard the SJ-10, a satellite that was launched into orbit on April 6 from the Jiuquan Satellite Launch Center in northwest China's Gansu Province.

"This research is a very first step for [we humans] to make interstellar travel and planet colonization come true," Enkui Duan, the principal investigator of the space mouse embryos project and a researcher at the State Key Laboratory of Stem Cell and Reproductive Biology in Beijing told me over email.


I caught Duan as he spent a sleepless night travelling to retrieve the mouse embryos (some of which survived) from Sizi Wangqi in Inner Mongolia—where the SJ-10 satellite landed on April 18—and back again to his team's lab in Beijing for further analysis.

"The experiment we have proposed in space was a big challenge. We boarded more than 6,000 mouse embryos on China's SJ-10 recoverable satellites by using our newly developed large scale mammalian embryo freezing and thawing technology," said Duan.

The embryos before launch, at the two-cell stage (not yet developed to blastocysts). Image: Enkui Duan

The team developed an embryo culture system and placed it within a small enclosed chamber that provides the ideal conditions for the embryos to develop in space. While the chamber was in orbit, a camera attached to the experiment took photographs of the embryos as they developed in microgravity, and sent these images back to Earth.

With the aid of their imaging technology, the researchers were able to observe how the mammalian two-cell stage embryos developed into blastocysts under microgravity after four days. Blastocysts are structures formed in the very early development of mammals. In humans blastocysts begin to form five days after fertilization.

The researchers will now compare their space-developed embryos to those cultured in normal laboratory environments on Earth to see what differences there are between the two at both a cellular and molecular level.

In the long run, the researchers are tying their research into the more broader issues of whether humans could survive and live healthily in space, whether they could have healthy offspring in space, and if short or long-term travel in space could affect human fertility owing to exposure to harsh space environments. In other words, they're dreaming big.


"The question we focused on is whether humans could achieve the dream of surviving and reproducing in outer space in the future," said Duan. "Now, we have finally proven that the most crucial step in our reproduction—early embryo development—is possible in outer space."

L-R Zheng WB (designer of embryo cultural box), Enkui Duan, Lei XH (embryo researcher) at the payload transfer area. Image: Enkui Duan

Duan and his team have been working on space reproductive technologies for the last couple of years, and they first attempted to develop mouse embryos in space back in 2006. That time, the team placed four-cell stage mouse embryos in the SJ-8 satellite, which beamed back high-resolution images of how those embryos were getting on.

"Unfortunately, all embryos failed to develop because of the high temperature in the culture system according to the data and images transmitted from the SJ-8 satellite," said Duan, who didn't give up.

He and his team spent the next few years persuading Chinese state officials that "failure is inevitable in the path of such space exploration," and that the team was set on succeeding if it was given a second chance. In the meantime, Duan also collaborated with researchers from the Shanghai Institute of Technical Physics in order to improve their space-faring equipment and in-lab culture systems.

Though Duan admitted that humans still had a long way to go before they can could colonize space, he was adamant that his team's project was a leap in the right direction.

"As we know, after the embryo develops to blastocyst, it must implant into the uterus then develop into a fetus. Next, we want to see whether the embryo developed in outer space could implant into the uterus correctly and develop into the final step—the fetus," said Duan.

"We will further still focus on the possibility of mammalian embryo implantation and subsequent development as well as human pregnant ability in outer space. Our final conquest, is the sea of stars."