Digging In at Oregon Moonbase:
Rockwell Robot Faces Moon Analog Test

Doug Helbling

Copyright (c) 1991

What kind of event could bring together a Rockwell aerospace engineer, a Bureau of Land Management realty specialist, an engineering/marketing team from WARN Industries, a U.S. Forest Service geologist, and Oregon L-5's Lunar Base Research Team? The testing of a new lunar winch cart robot design!

The robot is the brainchild of Steve Kent, of Rockwell International Space Systems Division. A long-term advocate of cost-effective space application of existing technology, Kent proposed the idea of the winch cart in a paper entitled "Prime Mover for Extraterrestrial Construction and Mining". He describes in detail the use of this general purpose robotic winch cart design in a number of applications. On May 1st, Steve put his design to the test.

Warn industries marketing manager Scott Salmon and design engineer Jerry Dilks were on hand to observe the performance of the Warn winch used on the robot. They provided the winch as part of a Rockwell/Warn cooperative agreement. Phil Paterno, the Bureau of Land Management's realty specialist for the Prineville area, was there to monitor the use of the Oregon Moonbase site, common practice for activities performed on land leased from the BLM. Larry Chitwood, U.S. Forest Service geologist, just happened to be checking in at the Oregon Moonbase site on other matters when the testing began. The Lunar Base Research Team, a group of space researchers from the Oregon L-5 chapter of the National Space Society, manage and administer the Oregon Moonbase site.

Preparation for the test started with assembly of the robotic unit, which had been broken down into several subcomponents for transportation from its original assembly point. After the unit was fully assembled, basic subsystem operations were checked and the unit was positioned for its most crucial test, anchoring into the soil with it's pair of auger units. The winch cart robot, or WCR, is intended to serve as a tow vehicle for a large variety of comparatively low technology earth and materials moving.

The basic notion of the WCR is to dig into the lunar soil and pull unpowered implements, like scrapers and rock sleds, from point to point. Keeping the electronics and other more vulnerable (and expensive) subsystems concentrated in the WCR, the costs of the total solution to lunar construction tasks can be minimized while increasing reliability at the same time. The implement towing concept is one that saw widespread terrestrial use around the turn of the century in farming applications, but where the pulling capacity of earth tractors is limited to roughly 60% of their weight, the low cost automotive type winch used with the winch cart can pull in excess of 200% of its own weight. This goes up in multiples as block and tackle are added.

The key element in the design is the auger mechanism used to root the WCR into the lunar soil. The original design contained only one auger, but the prototype tested had been modified to include two auger units. Either design version provides a machine that is theoretically capable of operating relatively independent of gravity, and may well operate in near zero gravity conditions.

LBRT researcher Tom Billings manned the video unit while fellow team member Bryce Walden positioned the still camera. The anticipation mounted among the support crew and observers as they stood poised in readiness for the test to begin. The test started, and the whir of the auger clutches howled back in close competition with the wind blowing through the scrub of eastern Oregon desert. The whir continued, with no visible digging taking place. The auger clutches were complaining, protecting the auger mechanism from the strain and resistance of the soil. The clutch design would have to be modified.

Disappointed but undaunted, Steve Kent continued other aspects of testing. He applied torque wrenches to the auger mount points to measure the resistance of the "lunar analog" soil at the Oregon Moonbase site to rotation of the auger blades. Unfortunately, a defective weld prevented much more testing in this area. Another design modification would be required before the WCR would be ready for lunar deployment.

Without the winches to anchor the WCR into the soil, testing of the winch mechanism would prove challenging. Manual simulation of the WCR boreholes, with help from LBRT researcher Cheryl Lynn York, gave the robot as close an approximation to normal anchoring as was possible under the circumstances. The winch was connected to a WARN staff vehicle to see if the vehicle, with parking brake locked, could be moved. The manual anchoring was not enough, however. This test would also have to wait until the auger situation was resolved.

Faced with a short term setback, Steve reviewed the data of the day, determined to incorporate the information from the tests and the feedback from the observers (including geologist Larry Chitwood) into his modifications for the WCR. The tests were not all successful, but the testing process was. Such efforts, performed as a standard part of the design implementation cycle, should result in space hardware that is space-ready when it leaves earth.

The Oregon Moonbase

The Oregon Moonbase is a project of The Oregon L-5 Society, Inc.. Oregon L-5 is a chapter of the National Space Society, an international group of over 25,000 people interesting in seeing "a spacefaring civilization" become a reality.

The Oregon Moonbase project is an effort by Oregon L-5's Lunar Base Research Team (LBRT) to establish a permanent lunar base research facility on the site of their 12-acre lavatube reserve in eastern Oregon. Leased from the city of Bend, Oregon (with supervision by the BLM), the site was used by long term members of the LBRT in their recent NASA study (NASW-4460) to characterize these caves as suitable analogs of lunar lavatube caves for more extensive lunar base research.

The Lunar Base Research Team has performed a number of research efforts at the site, in addition to their work conducting educational lunar mission simulations with the Young Astronauts program.

The Oregon L-5 Society, Inc.
P.O. Box 86
Oregon City, OR 97045-0007

Doug Helbling is a software engineer. After receiving an AA degree from Bismarck State College a dozen or so odd years ago, Doug migrated to Oregon, later graduating from OIT with a BSEE Technology degree. When he is not on the job, he can be found at home spending time with his wife and two daughters. His remaining idle moments, he says, are spent working with Oregon L-5, the local chapter of National Space Society, or in a dark room honing his SF skills.

doughe@bamboo.cax.tek.com