New technology may illuminate mystery moon caves

August 17, 2015, University of Wisconsin-Madison
NASA has been investigating features on the lunar landscape that may be "skylights," or openings to larger caves below the moon’s surface. This graphic features a number of likely skylights from the Marius Hills region.

It's widely believed that the moon features networks of caves created when violent lava flows tore under the surface from ancient volcanoes. Some craters may actually be "skylights" where cave ceilings have crumbled.

Since "lunar spelunking" expeditions aren't coming soon, the challenge is how to confirm the existence and dimensions of these with current remote imaging. A unique being developed at the Morgridge Institute for Research is providing NASA with an interesting and relatively inexpensive way to explore these out-of-sight features.

Andreas Velten, a Morgridge medical engineering affiliate and scientist with the University of Wisconsin-Madison Laboratory for Optical and Computational Instrumentation (LOCI), has developed a technology that fires and recaptures scattered laser light to literally "see around corners."

The system sends a pulse of laser light off of a wall or surface and into a nonvisible space. The scattering photons from the laser bounce off obstacles and make their way back to sensors in the camera. The dimensions of that unseen space are then recreated based on the time stamp of the photons that scatter back to the camera.

This technology is included in the NASA PERISCOPE project, which seeks to illuminate some of the more than 200 suspected lunar caves lurking under skylights. The ultimate goal is to include the technology on a satellite that orbits the moon at close range, directing laser pulses into suspected cave openings. The project is led by Jeff Nosanov, of Nosanov Consulting in Bethesda, Maryland.

The existence of lunar caves carries some enticing implications for planetary exploration, says Velten.

"Geologists are interested because they would provide access to subsurface geology without actually having to dig, which would be very difficult," Velten says. "There is potential for the discovery of water or other trapped volatiles under the surface."

Even cooler are the implications for future manned missions to the moon.

"What's interesting for space travel is you can't have people on the surface for long periods because of the temperature extremes, and because of radiation," Velten says. "But in these caves, people could survive for a long time with consistent temperatures and no radiation. Some of these may actually be quite deep, under 50-60 meters of rock."

Assisted by chemical engineering undergraduate Jessica Zeman, Velten completed a first phase using cave models this summer, and is beginning a second phase of field trials funded by a two-year, $500,000 NASA grant. Lava tubes created by volcanoes exist on Earth and are common in places like New Mexico and Hawaii. These tubes leave behind caves when the lava recedes, and they should provide Velten with geologic features comparable to the moon.

"These are likely much bigger than what we would encounter on Earth," he says.

In this example, the imaging system being developed for NASA sends a pulse of laser light off of a surface and into a nonvisible space to “see around a corner.” With an ultra-fast flash and high-speed camera, the system can reconstruct images of objects the camera never looked at. Credit: Andreas Velten

NASA has been interested in lunar subsurface exploration ever since the Lunar Reconnaissance Orbiter discovered cave skylights in 2009. The most important first step is to identify caves that are open and have features most worthy of future exploration. If Velten's technology can identify those, the next step may be robotic exploration.

The NASA Jet Propulsion Laboratory in Pasadena, California is developing robotic rovers that could investigate such caves. The rovers have a number of arms with small, sharp hooks—like cockroach arms—that would allow them to grasp rock and climb into cave walls and ceilings.

"Even though geology tells us there should be caves at these sites, we don't really know what's down there," Velten says. "We don't want to spend hundreds of millions on a rover mission, only to find a hole in the ground with the cave blocked in."

Velten's imaging , also known as a "trillion-frame-per-second camera," was first developed at the Massachusetts Institute of Technology (MIT). At Morgridge, Velten is developing new potential directions for scattered light imaging, including less invasive imaging of difficult to observe parts of the human body.

Explore further: Theoretical study suggests huge lava tubes could exist on moon

Related Stories

Russia eyes caves on moon for setting up a lunar base

October 20, 2011

For the time being, it appears NASA has set aside any ambitions to return to the Moon with human missions. But Russia may consider sending cosmonauts to the lunar surface to set up a colony using natural caves and possible ...

Down the Lunar Rabbit-hole

July 13, 2010

A whole new world came to life for Alice when she followed the White Rabbit down the hole. There was a grinning cat, a Hookah-smoking caterpillar, a Mad Hatter, and much more. It makes you wonder... what's waiting down the ...

New cave-dwelling arachnids discovered in Brazil

May 22, 2013

Two new species of cave-dwelling short-tailed whipscorpions have been discovered in northeastern Brazil, and are described in research published May 22 in the open access journal PLOS ONE by Adalberto Santos, from the Federal ...

Recommended for you

Google braces for huge EU fine over Android

July 18, 2018

Google prepared Wednesday to be hit with huge EU fine for freezing out rivals of its Android mobile phone system in a ruling that could spark new tensions between Brussels and Washington.

EU set to fine Google billions over Android: sources

July 17, 2018

The EU is set to fine US internet giant Google several billion euros this week for freezing out rivals of its Android mobile phone system, sources said, in a ruling that risks fresh tensions with Washington.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.