The Japanese satellite Kaguya has been gone a long time — it crashed into the surface of the moon in June 2009. But the data it collected nearly a decade ago is still revealing incredible lunar secrets, and the Japanese space agency JAXA confirmed Wednesday the existence of an enormous cave in the moon. It’s the perfect place for a moon base.
Kaguya first spotted a giant vertical opening in the moon’s Marius Hills region back in 2009, but it’s only now that analysis of the radar data has revealed just how big this cave is. It’s more than 150 feet wide and deep and is more than 30 miles long. That’s a ton of space for a potential lunar base.
The big advantage of building a base inside such a cave is the natural protection that it would provide from cosmic radiation. The moon has next to no atmosphere, meaning any longtime inhabitants would be exposed to cosmic rays that we don’t have to worry about here on Earth, where we are naturally shielded.
While we certainly could come up with a way to protect ourselves — and we’re going to have to, if we want long-term habitation of worlds like the moon or Mars— the cave could do the job for us.
There are other advantages, according to JAXA. The cave interior would also shield astronauts from meteorite impacts — again, more of a concern on the moon than on Earth because of the lack of atmosphere — and it would also have a more stable temperature.
It’s thought that this cave and others like it are lava tubes, created by volcanic blasts some 3.5 billion years ago. The team’s full findings are presented in the latest issue of Geophysical Research Letters.
Oct 19, 2017
Detection of intact lunar lava tubes in the data from SELENE (Kaguya) radar sounding
Main points of this study
A new result based on the data from the Lunar Radar Sounder onboard SELENE(Selenological and Engineering Explorer/ Kaguya)
Detection of a 50-km long intact lava tube underground along a lava flow river “rille” on the Marius Hills of the Moon
This research result is very significant because lunar lava tubes have unique values for both science and human expansion to space:
1) We can obtain valuable lunar rock samples that have not been brecciated, fragmented, or space-weathered, and thus may contain gases (including water) trapped in the past, and also may have maintained records of the past intrinsic magnetic dynamo field. Lunar lava tube also offers analog environments that can provide insights into Martian subsurface lava tubes, where Martian life might have emerged and perhaps might even survive to this day.
2) Lava tubes may be the best place to build large-scale lunar bases because their interiors protect from dangerous space radiation, micrometeorite bombardment, and wide temperature oscillations.
Outline of study
Lunar lava tubes, or subsurface caves formed by lava flows, are important from the perspectives of both science and human exploration. If they exist, they might be the best candidate sites for future lunar bases, because of their stable thermal conditions and potential to protect people and instruments from micrometeorites and cosmic ray radiation. The same stable and protected environment that would benefit future human explorers also makes them an enticing science target: original lava compositions, textures, and even magmatic volatiles are expected to be preserved in pristine condition within these lava tubes. Careful examination of their interiors could provide unique insights concerning the evolutionary history of the Moon.
In 2009, large, deep vertical holes were discovered at Marius Hills, Mare Tranquillitatis, and Mare Ingenii using lunar surface image data acquired by the high-resolution Terrain Camera (TC) onboard SELENE (Kaguya). Later, higher resolution nadir and oblique angle observations performed by the Lunar Reconnaissance Orbiter Narrow Angle Camera confirmed that the floor of the holes extends at least several meters eastward and westward under the ceiling. The three biggest holes on the Moon are possible skylights opening into an ample space. However, whether these large spaces are subsurface lava tubes is still unknown.
The Lunar Radar Sounder (LRS) onboard SELENE consists of two sets of dipole antennas transmitting electromagnetic (4-6MHz) waves and receiving echoes from the Moon. We used radar echo data from the LRS to investigate the existence of underground lava tubes at Marius Hills