Observation data collected by Japan’s lunar orbiter Kaguya has found a cave stretching about 50 km (30 miles) on the moon that could potentially serve as a shelter for astronauts on future missions, an international research team including the Japan Aerospace Exploration Agency has said.

The cave could protect astronauts from radiation from the sun and cosmic rays if they build a base for exploration, the team said Wednesday.

The cave, believed to be a lava tube created about 3.5 billion years ago, sits beneath an area with a group of volcanic domes called the Marius Hills, it said.

The lunar orbiter initially found a hole about 50 meters in diameter and depth. Further surveys of the area with radio waves discovered the lava tube, the researchers said.

The cave is believed to have a width of several tens of meters.

Like caves found around Mount Fuji and the island of Hawaii, the cave on the moon is highly likely to have been formed after the lava surface solidified following a fall in temperature, according to the researchers.

“The cave is a scientifically useful place,” said Tetsuya Kaku, a graduate student at Tokai University involved in the study. Kaku cited the possibility of finding minerals produced when the moon was formed as well as water.

The researchers published their finding in U.S. journal Geophysical Research Letters.

KEYWORDS space, JAXA, satellite, moon