What Time Is It on the Moon?

In 2025, astronauts will begin returning to the moon, eventually building bases and space stations, putting robotic landers and rovers to work, and mining for resources. In this bustling new era of lunar activity, they'll need to synchronize with each other. But so far there is no agreed-upon time system or zones, and there's neither GPS nor internet on the moon. Setting those up will require developing new technologies on Earth to be deployed 239,000 miles away. Javier Ventura-Traveset, an engineer at the European Space Agency, is leading this work with a project called Moonlight, which aims to design satellites for astronauts and robotic explorers.