Mouse embryos have been grown on the International Space Station and developed normally in the first study indicating it could be possible for humans to reproduce in space, a group of Japanese scientists said.

The researchers, including Teruhiko Wakayama, professor of University of Yamanashi's Advanced Biotechnology Centre, and a team from the Japan Aerospace Space Agency (JAXA), sent frozen mouse embryos on board a rocket to the ISS in August 2021.

Astronauts thawed the early-stage embryos using a special device designed for this purpose and grew them on the station for four days.

"The embryos cultured under microgravity conditions developed" normally into blastocysts, cells that develop into the fetus and placenta, the scientists said.

The experiment "clearly demonstrated that gravity had no significant effect," the researchers said in a study that was published online in the scientific journal iScience on Saturday.

As yet another space rocket is launched and more technology is placed into orbit, the problem of space junk grows and grows, not to mention the pollution from all the fuel burned en route.

A review in the International Journal of Student Project Reporting has looked at possible solutions to the problem of the abundance of space junk. Jennifer Stein, David Castillo, Elise Bedell, Erriana Thomas, and Nicolas Valiente of the University of Florida in Gainesville, Florida, U.S., have looked at whether there are cost-effective, environmentally benign, and efficient methods that might be used to minimize the harm from debris in space, which can damage other craft in orbit, potentially harm astronauts, and represent a risk when it falls to earth.

Space junk can be defined as non-functional man-made objects that remain in near-Earth orbit. There is growing concern regarding such debris as there is no way to track it all, especially debris less than 10 millimeters or so in width nor to allow for potential hazards to spacecraft and satellites. Anything larger can be monitored and tracked with telescopes or radar.

Some 30 years ago, a young engineer named Christopher Walker was home in the evening making chocolate pudding when he got what turned out to be a very serendipitous call from his mother.

Taking the call, he shut off the stove and stretched plastic wrap over the pot to keep the pudding fresh. By the time he returned, the cooling air in the pot had drawn the wrap into a concave shape, and in that warped plastic, he saw something—the magnified reflection of an overhead lightbulb—that gave him an idea that could revolutionize space-based sensing and communications.

That idea became the Large Balloon Reflector (LBR), an inflatable device that creates wide collection apertures that weigh a fraction of today's deployable antennas.