1. [#6001] Mars Deep Drilling Remains a High Priority
   
2. [#6002] Drilling to Extract Liquid Water on Mars: Feasible and Worth the Investment
3. [#6004] Report on the Construction and Testing of a Bucket Wheel Excavator
4. [#6034] Lunar and Martian Fiberglass as a Versatile Family of ISRU Value-Added Products

1. Colorado School of Mines
2. Lunar and Planetary Institute
3. Norcat: Northern Centre for Advanced Technology Inc.
4. Planetary and Terrestrial Mining Sciences Symposium

In 1992, The University of Texas Center for Space Research (CSR) submitted a proposal to the NASA Scout Program to drill a “deep” well on Mars. The proposal was unsuccessful. However, the mission remains viable, and can still be accomplished for a very low cost. The science of this mission remains of utmost interest to the science community, and no deep drilling mission is scheduled currently. Deep drilling is the only way to verify the character of the Martian subsurface, particularly to characterize any water to be found there, and eventually to
explore for liquid water.

During the preparation of the Scout proposal, a very strong team was forged, and several of the team members, including NASA Centers, have expressed a strong interest in pursuing this mission in the near future. In its existing programs (GRACE, ICESAT, others), CSR has developed strong international ties, particularly with Germany. The GRACE partnership resulted in a sharing of mission expenses between the two countries. This type of partnership remains very viable for a Mars Deep Drilling Mission.

Baker Hughes, Inc., and the NASA Johnson Space Center have built and tested a prototype Mars deep drill, so the technology risk has been greatly reduced. All of these factors come together to suggest that a very low cost, low risk mission can be proposed to NASA, either in response to a future Scout mission call, or as an independent international mission.

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A critical application for the success of the Exploration Mission is developing cost effective means to extract resources from the Moon and Mars needed to support human exploration. Water is the most important resource in this regard, providing a critical life support consumable, the starting product of energy rich propellants, energy storage media (e.g. fuel cells), and a reagent used in virtually all manufacturing processes. Water is adsorbed and chemically bound in Mars soils, ice is present near the Martian surface at high latitudes, and water vapor is a minor atmospheric constituent, but extracting meaningful quantities requires large complex mechanical systems, massive feedstock handling, and large energy inputs. Liquid water aquifers are almost certain to be found at a depth of several kilometers on Mars based on our understanding of the average subsurface thermal gradient, and geological evidence from recent Mars missions suggests liquid water may be present much closer to the surface at some locations. The discovery of hundreds of recent water-carved gullies on Mars indicates liquid water can be found at depths of 200-500 meters in many locations. Drilling to obtain liquid water via pumping is therefore feasible and could lower the cost and improve the return of Mars exploration more than any other ISRU technology on the horizon. On the Moon, water ice may be found in quantity in permanently shadowed regions near the poles.

A system of modular, reconfigurable, autonomous and human-tended deep drilling technologies should be developed for use initially on Mars precursor missions and later for subsequent crewed missions that are less mass and power constrained. For the Mars application, the drilling technology will be focused on obtaining liquid water via pumping for resource utilization purposes. Early testing on the Moon could be used to establish viability of this technology so that it can be a cornerstone architecture element of Mars exploration, as well as a tool for resource exploration and science. The required technologies for the Moon and Mars have much in common but there are important differences. On the Moon, directional drilling is likely to call for the use of a conventional drill string (similar to one under development for robotic Mars application) and a steerable down-hole unit. Hole stability in the lunar regolith will require the use of casing or of microwave sintering. Exploitation of lunar resources identified by drilling will subsequently be a mining and processing operation. On Mars the main task will be deep penetration to gain access to liquid water. Penetration to depths of kilometers would require massive equipment if a drill string is used but could be implemented using a wire-line device (one that anchors itself to the bottom of the hole and exerts force on bit from there rather than from the surface) where additional depth penetration requires only the addition of more cable. Its advantages include lightweight and convenience in automating its control since digital data can be more easily communicated. Mars ISRU goals will involve gaining controlled access to liquid water that can be pumped to the surface. Because of the stabilizing effect of ground ice, much of a Martian drill hole may not need stabilization. Preventing bit freeze up may require controlling bit temperature, and cuttings removal may require use of low temperature drilling fluids, such as liquid CO2 derived from Mars air. It may also be necessary to line the hole with an insulating material to ensure that water does not freeze on its ascent to the surface.

Drills developed for robotic Mars mission applications have been field tested to 10 m depth. Deeper depths suggest a wire line drill string (downhole motor driving the bit) suspended on a cable and an elevator bailer to remove cuttings. Design issues to be addressed for a deep drill include operational simplicity and low mass, bit development and change-out strategies to respond to bit wear and the need to cut a range of materials, cuttings removal approach, systems for anchoring the drill string in the hole and providing weight on bit, casing for hole stability and capping to prevent destructive effects of pressure differentials. While NASA Code S has recently invested in technology development for robotic drills for Mars exploration (and useful progress has been made) the investment is not consistent in scope with the new Space Exploration vision.

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by Gary "ROD" Rodriguez, Systems Architect, sysRAND Corporation

Lunar Regolith consists principally of silicates, in some cases as volcanic or impact glasses. We continue to contend that silicon is more versatile in application than all of the other Lunar available elements combined and shouldn't end up in Lunar slag heaps and instead should be the fundamental building block for a wide range of value-added products in a CisLunar economy. Fabrication of silicate glasses are conventional industrial processes and anticipated tensile strength of glass made under hard vacuum is an order of magnitude greater than glass produced in atmosphere containing water vapor.

The logic employed in our reasoning includes the fact that any In Situ Resource Utilization (ISRU) effort is going to yield copious masses of silicon oxides which can be used in bulk as conventional glass products or, after further separation, can be synthesized as Silicon and Silicon- Carbide Fullerenes for more exotic applications. Additionally, mechanical wrapping of Silicon Webbing could prove to be more practical and durable and a lot less brittle than attempting large scale hot glass molding of structural components.

Identified fuel production ISRU efforts yield partially heated masses of metal oxides as waste byproduct – rich in silicates and metal oxides useful in bulk as conventional glass products. Fiberglass manufacturing increases effectiveness of prior ISRU fuel production by taking advantage of mineral benefaction and elevated process exit temperatures. The resulting structures would be spheres and cylinders with various configurations that could apply to human support systems, along with structures useable as storage tanks for the very Oxygen liberated in ISRU applications.

ISRU can manufacture more than fuels: even spacecraft are feasibly and affordably manufactured on Moon based upon fiberglass "tankage" integrated with fiberglass keels. Second generation structural components may take advantage of Silicon Nanotubes for additional composite strength. Diverse products for human systems support are manufacturable in-situ using glass fibers and fabrics, and CNC-type programmable manufacturing delivering state-of-the-art flexibility of remote design and parts manufacture. These concepts suggest extensibility and evolutionary capability derived when machining tool parts from fiberglass.

Contemporary Terrestrial industrial composite fiber products range from pressure vessels to lightweight sporting goods. A large number of products related to human systems support can similarly be manufactured in-situ using fiber fabric made from lunar silicate glass. Building structures using spun glass would be similar to those currently employed by Raytheon Aircraft or Scaled Composites to build composite aircraft. Pressure containers, structural components, woven fiberglass fabrics, molded and machined solid objects, glass fiber and filament are each large classes of value-added products.

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