Site of the Oregon Moonbase: Young's Cave complex near Bend, Oregon, is a crosslinked pair of lava tubes. It has been thoroughly investigated for its potential to support simulated lunar base activities of various kinds, with many potential users. We report on this outstanding NASA-supported project of the Oregon L5 Society NSS chapter, and the prospects for future site development.
With the help of a NASA Grant, 3 Oregon L5 Society chapter members have investigated the potential of a unique site in their geographic backyard to support lunar base simulation studies of various kinds.
Report by Peter Kokh
For wildlife, it must have been the depths of hell. Repeatedly, between 17 and 11 million years ago, tensions in the bowels of the Earth split the surface apart between the Cascades and the Idaho Rockies in what is now Oregon and Washington. Runny silicon-poor lava poured out of multiple fissures to form 2000o F floods of red death, as much as a hundred miles wide, advancing at an merciless pace, literally disintegrating animals large and small unfortunate enough to have made a misstep or taken a wrong turn or stumbled in a stampede or simply fallen exhausted from the endless urgent retreat. Such wholesale purges of the area's flora and fauna happened over and over in episodes typically 10,000 years apart, long enough to allow a teasing Sisyphus-like recovery.
In the process, old valleys and lower hilltops alike were buried under an accumulation of basaltic blankets up to hundreds of feet thick - an estimated total of 77,000 cubic miles (in comparison, Mt. St. Helens released 1/2 cubic mile of material). It is in this context that a number of lavatubes formed in the Bend, Oregon area, when rivers of hot lava within a cooling sheet drained out into lower-lying basins, leaving relic cavities behind. Similar features honeycomb the slow gentle slopes of Hawaii's great shield volcanoes, features likewise formed by runny pahoehoe lava (thicker more viscous lava builds up tall cones).
Some four years ago, just a month before the March 1987 L5/NSI merger in Pittsburgh, Oregon L5 chapter leader Bryce Walden, who had read F. Horz's article "Lava Tubes: Potential Shelters for Habitats" in the 1985 "Lunar Bases and Space Activities of the 21st Century" edited by Wendell Mendell, was present during a Young Astronaut tour of the Portland Air National Guard Base. He suggested a YA field trip to a lava tube near Bend, a proposal which was greeted with enthusiasm. After a chapter team visited many potential sites that spring, a simulation exercise was actually held at Skeleton Cave. The mission tested organization, design, logistics, construction, human factors, and educational opportunities. Included were a surface camp and a 'lunar base' 470 meters inside the cave. This consisted of a sleep/work platform, a communications desk, a galley, and a sanitation facility. Mission science included cave mapping, astronomy, geochemistry, and environmental monitoring. The city of Bend, properly impressed, then offered the use of Young's Cave, a site less visited and less disturbed by visitors and tourists. A third simulation was run there.
[The 12 acre Young's Cave site is owned by the U.S. Bureau of Land Management, but the City of Bend Dept. of Public Works holds the land patent as part of its wastewater treatment plant site, a half mile to the north. Bend has given Oregon Moonbase a 5-year renewable lease to the site for research & education purposes.]
The following year, the Oregon L5 team, after networking with the AAAS, Lockheed Engineering and Sciences, and the Oregon Grotto of the National Speleological Society, began in depth research of the concept of an outfitted lavatube as a site for ongoing professional lunar base simulation activities of various kinds. After exploring many scenarios for use of lunar lavatubes, the team prepared nine proposals for NASA's Office of Exploration Innovation Outreach Program. The day after the 20th anniversary of the Apollo 11 Moon landing, NASA announced the acceptance of one of these: "Site Characterization of the Oregon Moonbase".
After months of contract negotiations, funding was received in March 1990. Meanwhile the team was busy publishing and networking, and circulating Users Surveys to 300 potential interested parties. [MMM/LRS received one of these and was intensely interested, but chose not to reply because there appeared to be no realistic scenario by which we could find the funds to use the site in any of the ways which occurred to us. Some of our suggestions, which apparently have not occurred to other potential users, are indicated near the end of this article.]
Terrestrial lavatubes are typically 10-30 meters wide and a few kilometers long at best. All indications are that their more ancient lunar cousins are more than an order of magnitude larger, 300-500 meters in width and height with 'roofs' 40 meter or more thick, and many kilometers long. There is every reason to believe the slopes of the great Martian shield volcanoes are laced with similar features on an intermediate scale. In any case we are presented with voluminous shelter from the cosmic elements (cosmic rays, solar flares, solar ultraviolet, most meteorites, and wild surface temperature swings).
These handy features have endured unused and intact for a billion years in the case of Mars, and for 3 plus billion years in the case of the Moon. In contrast, our typical limestone cave lasts only a few hundred thousand years in the context of Earth's active geology. Such places can offer primary shelter for lunar bases of considerable size, or ready room to grow, especially for the area-intensive needs of industry, agriculture, and storage. Too large to seal and pressurize, they offer safe haven for cheaper pressurized structures such as inflatables, and will allow those working within to wear lighter weight pressure suits instead of bulky hard suits, leading to a quantum leap in EVA safety for construction workers. The advantages are so clear, that it would be blind dead-end folly to deploy a major surface base without a suitable lavatube close at hand for earliest expansion. With such an option, the actual surface installation might even be kept minimal.
Lavatubes occur in the relatively flat mare (lunar "sea") areas, typically near to highland "coasts" thus providing a site where industry has access to both suites of materials. Possibly the only refuge from troublesome lunar dust (spallation debris on the tube bottoms will not have been micro-pulverized like the surface regolith blanket - Martian tubes may include wind and flood-borne sands, even ice), lavatubes also commonly offer other handy features: roofs strong enough to support suspended structures like habitats and transport systems above uneven floors, handy sidewall benches, areas of level floor created by cooling pools, frequent mid-floor channels in which to lay utility service runs, etc.
For the purposes of executing the grant project, the Oregon Moonbase Team has been headed by Cheryl York (fka Singer) as principal investigator and includes Walden and Tom Billings as researchers. It next set about doing a thorough site characterization, essential before planning development of a facility that would support the sort of uses envisioned. Young's Cave was thoroughly mapped, the structural strength of its walls and roof assessed by an engineering firm. The surface area was also mapped and characterized. Geological, environmental, and archeological assessments were likewise contracted out to qualified parties.
Once popularly known as Kegger Cave, Young's Cave consists of two main East and West passages roughly 900 and 1100 feet long respectively, gently sloping only a few meters along this length. These main passages are connected by a low intermediate passage that is nearly blocked. Nearby Stepladder Cave, Hidden Cave, and Roadside Cave were evidently once part of the same complex but connectors have been blocked by lava plugs or sinkholes. These caves are part of a long system of lavatubes in the Bend area running in a general line from SSW to NNE. The cross-sections are generally semicircular, the lower portion having been filled by a late flow (there were apparently multiple episodes) that did not fully drain.
The width varies, alternately pinching and swelling. There are areas of breakdown, some early, some recent, with scattered debris piles. There is a layer of sand fill deposited and rearranged by wind currents and water (both of which are absent on the Moon, but at work on Mars). The Geological survey was done by Stephen L. Gillett, a consulting geologist now in Carson City, Nevada. Steve is a member of Seattle L5 and longtime reader and sometime contributor to MMM.
Century West Engineering of Bend did the engineering analysis. A series of borings shows the roof to be generally from 10 to 20 feet thick with 7-19 ft of hard basalt overlain by 0-3 ft of loose soil. Except for a few transverse cooling cracks, the ceiling is relatively intact and rock quality analysis shows the roof should support from 2-60 tons suspended weight per linear foot, depending on the varying roof thickness and the presence or absence of fractures. For this purpose, a system of rock bolts will do. In some weak areas, roof-shoring supports are advised. There is an estimated 6000-7500 cubic yards of sand fill on the floor ranging from 0-6 ft thick as measured by a series of hand-auger holes. This could be removed, if desired, by vacuuming. Rock debris could be removed, if and where desired, by back hoe or by hoists through openings made in the roof, thereafter available for installation of equipment. The shape of surface terrain was also surveyed. Development of the future Oregon Moonbase facility may include some removal of sand and debris, stabilization of some weak roof areas, and some excavations into the basalt walls, floor, and roof.
The USER SURVEY was returned by 33 interested parties (out of 300 addressees). Proposed uses include simulations of automated and crewed Moon and Mars missions, expedition design, testing and demonstration of base systems and subsystems (shelter and habitat, life support, power and control systems, surface systems), resource development, geological and planetological studies, and education. Potential users include NASA, aerospace industry professionals, educators and consultants. Most users indicated the similarity to expected lunar & Martian conditions (verisimilitude) outweighed the remoteness of the proposed facility.
An analysis of user needs indicates "the proposed facility should focus on two main areas: surface/subsurface/subsurface-equipment interaction (construction and excavation techniques, transportation, access) and integration." Short-com-ings include the lack of vacuum and lunar 1/6th gravity, about which nothing can be done, and the lack of a lunar dayspan/nightspan cycle, which can be easily simulated underground as needed. As many groups wish to work with full-scale habitation and life-support systems, the facility must provide adequate support systems (power, water) upfront. Eventually, permanent habitation modules will be desirable for on-site housing of the user personnel. As the facility develops, the educational potential will grow with it, from YA mission simulations to public tours and professional seminars.
One whole suite of potential use seems absent from the gamut of suggestions contained in the returned user surveys: materials processing based on basalt. Even though the common basalt in this area is a less faithful analog of what we have found on the Moon than the Mid-Continent Rift basalts used as the basis of the standard Minnesota Lunar Simulant, useful work in crude processing methods could be done at this site. Working with low-tech (thus lunar-appropriate) Cast Basalt to fabricate a wide range of products (from tableware to performance-light structural elements) suggests itself. Based on materials research done on site and elsewhere, a visitors' center could be partially built (or expanded) and furnished with sample items to illustrate the possibilities for lunar base self-reliance to the public. A portion of the cave complex artificially illuminated according to a lunar dayspan/nightspan cycle could house a number of agricultural modules and bioregenerative life-support research and demo units.
The current ambition of the Oregon Moonbase Team is to develop and operate a facility in the wide niche between highest realism/highest cost (i.e. the Antarctic Dry Valleys) and low realism/low cost (i.e. the lab). Some of the work proposed for the site would actually not demand that faithful an analog to lunar lavatubes. Light cycle dependent work, for example, could be done in any appropriately sized limestone cave or even in a large hanger. Even so, the interaction between users at the Oregon Moonbase will confer a matchless advantage to doing work there.
Such an expenditure would be cheap insurance that whatever NASA, other agencies or even private enterprise eventually might deploy on the Moon or elsewhere will work as advertised.
A proposal has been submitted for Phase One Development, the minimum necessary to serve the least demanding potential users, and Phases Two to Four are in process of definition. Phase One will include a Facility Operations Center, a dedicated Teleoperations Center, a powerhouse, lighting systems, water heating and storage, food preparation and storage, general and hazardous waste handling, security and safety systems, plus access and communications systems.
All this will cost money, an estimated $6.2 millions over four years. But such an expenditure would be cheap insurance that whatever NASA, other agencies or even private enterprise eventually might deploy on the Moon or elsewhere will work as advertised.
We can only hope that "the powers that be" realize that this facility is not another luxury but an investment that fills an essential need on the critical path towards the realization of a spacefaring civilization, in accordance with the Space Settlement Act of 1988. It would be a good omen for all of us if the funds needed to begin Phase One development are forthcoming in a timely fashion.
Our hats off to the Oregon Moonbase Team. If all NSS chapters had people as dedicated and determined as this one, who could doubt that the realization of a spacefaring civilization would be guaranteed? While the natural endowment of their chapter hinterland provided them with this splendid resource and opportunity, this writer has no doubts that if they had not been so blessed, they would have found some other way to play a major role. Their work should inspire us all and demonstrates that there IS a place for chapter activity beyond the traditional roles of grass roots activism. MMM