Moon Miners' Manifesto

#100 November 1996

Robotic On-Site Exploration and Surveying of Lava Tubes

Peter Kokh

We are back on the Moon, to stay it seems, and we've detected a number of lavatubes from orbit, some handy to our first beachhead outpost. The catch is that there are so many things needing priority attention that we cannot afford the manpower and equipment costs to outfit even a single lavatube exploration expedition. But if we don't "go in" and actually explore and survey, how can we plan intelligently to "move inside" in concrete particulars?

Here is a way we can survey in detail all the lavatubes we have detected remotely from photographic evidence, from orbiting radar and infrared equipment. The costs, in comparison to a single limited human expedition, would be negligible.

A surface crawling drilling rig, using high-resolution orbital radar lavatube location data, finds its initial drill point over an indicated tube site. This rig can be teleoperated or manned. Given the repetitive nature of the tasks involved, a highly automated remote monitored operation will be ideal.

(1) Its first task is to drill and stabilize (with a sleeve? with side-wall fusing or sintering lasers?) a hole through the surface and penetrating the lavatube ceiling some tens of meters down. The hole might be only a few inches in diameter.

(2) Next the rig winches down through the shaft hole a radar-mapping instrument and/or CCD optical camera down to a height midway between lavatube ceiling and floor (determining that position is the first task of the radar device). Then a flare attached to the bottom of the instrument package is released and dropped. The radar mapper and camera pan 360^o, and from near vertical up (zenith) to near vertical down (nadir) and back up on the other side. The instrument package is retrieved. A latitude/longitude/altitude benchmark is then lowered to the tube floor directly below.

(3) The rig then winches down to the same point a length of fiber optic cable, securing the top end to the collar of the shaft hole. At the top end is a solar light concentrator which passively gathers available dayspan sunshine and channels it into the optic fiber cable. At the bottom end a light diffuser scatters this light in all directions. The idea is not to provide future human explorers within the tube with enough light, throughout the surface dayspan period, to find their way around with the naked eye, but only with enough light that they can find their way using off-the-shelf night-vision goggles. Of course they will carry battery-pack spotlights to light up areas needing closer inspection, as well as for emergencies (e.g., they are forced to stay inside after local sunset on the surface above).

(4) Meanwhile, data from the radar/camera probe is being turned into a contour map of the lavatube's inner surfaces. From this map, it will be clear in which direction the lavatube runs and the location of the next drill hole can be determined, picked so that data from it (and the reach of the left behind "solar flash-light" overlap conveniently).

As the instrument package is removed from each successive shaft hole, another passive solar flash light chandelier is installed. On and on until the entire intact lavatube is surveyed from source to outflow. The rig then moves to one end of the next orbitally detected site to be investigated.

The result will be a set of tube surveys and maps from which preliminary rational use scenarios can be put together, all prior to commitment of manhours and man-rated equipment packages. Now, with all of these robotic surveys safely made, when we do go in to explore or set up shop, we can be sure that the tube section picked is right for the purpose intended, including the offer of adequate expansion room for foreseen development options.

This is the basic idea. Possible embellishments are designing the solar flashlight chandeliers to serve as line-of-sight relays for radio communications by exploring crews and/or as direct radio antennas to the surface.

If the tube surveyed by the surface-crawling robot drilling rig has already been picked for future development, a "sleeve-bag" of sundry provisions and resupplies could be lowered to the tube floor beside the benchmark before sealing the shaft with the solar light fixture apparatus. These provisions would lighten the in-tube explorers' burden. Alternately, the solar light fixtures could be removable if the shaft is needed for lowering provisions or other narrow diameter equipment to the area below it.

This exploration plan will only work, of course, for those near-surface tubes that have been sniffed out by our orbiting probes. But that will be an important start!

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