Japan’s lunar orbiter discovers moon cave potentially suitable for use as shelter
https://www.japantimes.co.jp/news/2017/10/18/national/science-health/japans-lunar-orbiter-discovers-moon-cave-potentially-suitable-use-shelter/
Observation data collected by Japan’s lunar orbiter Kaguya has shown that a cave stretching some 50 km (over 30 miles) exists on the moon that could provide shelter for astronauts in the future, the Japan Aerospace Exploration Agency said Wednesday.

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

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 agency, also known as JAXA, said.
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(日文相關資訊)
月の地下に巨大な地下空洞発見　月周回衛星「かぐや」のデータで判明
月基地建設にも使える。
http://nlab.itmedia.co.jp/nl/articles/1710/18/news112.html
宇宙航空研究開発機構（JAXA）は、日本の月周回衛星「かぐや」に搭載された電波レーダで取得したデータにより、月火山地域の地下数十メートルから数百メートルの深さに複数の空洞が確認されたと発表しました。確認された地下空洞には数十キロ伸びた巨大なものもあったとのこと。
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日本宇宙航空研究開發機構（JAXA）放去月球探測的衛星 「かぐや」號，探測到月球上有直徑50km大的地底洞，這洞穴未來或可作為探月太空人的庇護所 (月球基地)。