Generation II Mars Settlement Study Update
2nd Atlanta Workshop, Part 1
Report Date: May 2007
Meeting Date: March 9-12, 2007
Reported by Brian Enke, Gen II Documentation Lead
"The future cannot be predicted, but futures can be invented."
- Dennis Gabor, 1971 Nobel Prize winner: Physics (Holography)
Over the past year, the authors on the 4Frontiers short-story fiction writing project have pondered a difficult question. How can we “predict” a future Mars settlement as accurately and thoroughly as possible? A lot will happen between now and 2037. Political winds will shift. Technological innovation may accelerate or stagnate. NASA and private enterprise might get serious about space settlement and commercialism… or not. Environmental fears could become a distraction or an enabler. Perhaps the great philosopher Yoda offers advice as wise as Gabor: “Always in motion the future is."
So how should our authors bring this future settlement to life? With all due respect to Master Yoda, Gabor’s words are far more useful. Futures can be invented.
We can predict the thousands of “nuts and bolts” necessary to create a Mars settlement by inventing them. This spirit drives the 4Frontiers Corporation, and the same spirit motivated 20 researchers, engineers, and yes – authors, to travel to Atlanta for the second Gen-II Mars Settlement Workshop.
As he did for the first Gen-II workshop in October, 2006, Dr. Richard Sylvan graciously offered his home in the Atlanta suburbs as our meeting site. Most of the participants arrived on Friday afternoon (March 9) and stayed through Sunday evening (March 11). Members of the “core” team stayed an extra day to document the proceedings and plan future directions. Minus an occasional traffic jam or lost cell phone (mine, sigh), our travels were uneventful.
The same “can-do” attitude, flexibility, and commitment ruled the weekend. Intense, non-stop discussions and sharing of ideas, goals, dreams, and obstacles banished any thoughts of sleep on Saturday night. Lighter moments were filled with JibJab and YouTube videos of ManBearPig, David Elsewhere, and the infamous “This Land is Your Land” (though for some reason, neither Bush nor Kerry claimed Mars as “their land,” hmmph).
Attendees of the 2nd Gen II Atlanta Workshop. Front row from left to right: Kristin Showalter, Mark Homnick, Jeremy Sotzen, Bebe Kelly-Serrato, Grant Bonin, Nathan Owen-Going, Bob Milligan, Frank Crossman. Back row from left to right: Richard Sylvan, Ned Chapin, Pablo Rivera, Brian Enke, Joseph Palaia IV, Michael Carroll, John Graham, Paul Graham, Vernon Kramer, Scott Patterson, Michael Rudis, Michael Busch (Click image for larger view).
Those who stayed up late (or never went to sleep) also experienced a rare temporal event – the 2:00am time change for daylight savings time! Strange – one moment it’s 2:00am, and the next it’s 3:00am, raising thoughts of Kim Stanley Robinson’s 36-minutes of dead-time each evening on Mars (but in reverse). Fortunately, better Martian timekeeping systems will save future settlers from the hassle of dealing with frozen clocks.
Saturday: A Different Type of Meeting
At 9:11am, Saturday morning, CEO Mark Homnick laid the groundwork for the weekend by promising “a different type of meeting.” Last time, we were up in the sky, discussing generalities. Now we would drop down into the trenches. This meeting would emphasize design details - how every piece of every subsystem relates to the overall concept. Each team leader would give a 20 minute presentation, plus time for discussion.
Location, Location, Location...
Michael Rudis started the presentations by describing the recent decision to “move the settlement” from Chandor Chasma (Valles Marineris) to Terra Meridiani (near the site of the Opportunity rover). While generating a lot of discussion and questions, the decision to move the settlement illustrated two important lessons: 1) We need far more on-the-ground scouting of other locations on Mars before those locations can become viable settlement sites; 2) Sometimes, while staring deeply into the face of the unknown, you just have to make a command decision. All future base planning will assume a location of Terra Meridiani because it’s the best choice, given what we know about Mars at this point in time.
Hydrogen signature in the Terra Meridiani region.
Source: Neutron spectrometer on the Mars Odyssey orbiter (Click image for larger view).
Orbiter data, with ground-truth from in-situ rover observations, suggest several potential base locations in the Terra Meridiani region within 100 kilometers of key mineral deposits. We should locate the base near high concentrations of iron (hematite) and hydrated minerals (gypsum, clay, epsomite, jarosite, kieserite). Outcrops in Terra Meridiani (or just about any other region of Mars) will allow settlers to bury parts of the base under one to twenty meters of regolith, depending upon function, structure, and need for radiation shielding. Mild wind patterns, an equatorial location, and flat, surrounding plains make Terra Meridiani an ideal landing site for cargo shipments from Earth.
Oh Build Me a Home...
Michael transitioned his presentation into architectural issues, including construction techniques and the newest “space matrix.” Under one scenario, engineers would use draglines to bury structures. The sheer volume of regolith will make the operation difficult, but feasible. Some structures will need partial pressurization (more later). Foundations are critical; will concrete slabs with deep pilings be adequate?
Gen-II apartment modules will be two-story units! Architects will give hungry Mars settlers a small kitchen area on the second floor of each unit, complete with a microwave or hotplate. The second floor also features a spacious living room and a small table. A 9-foot, round window, centered in the floor between levels (see illustration below), provides a stunning view of the outside world on both levels. The diameter of each unit will be six meters. Leveled concrete pads and arched foundations will ensure the structural stability of the concrete walls.
Early architectural sketches of a habitat module.
Habitat construction illustrates the three primary environmental differences on Mars that affect construction techniques: gravity, raw materials (contaminants), and air pressure. Gravity can’t be controlled or modified. However, pre-processing and contaminant removal would allow the use of known construction materials like a Portland-style concrete that could survive the high levels of humidity within portions of the settlement. However, Portland-style cements require air pressure to cure, leading to a requirement for partially pressurized construction hangars.
The various structures within a Mars settlement will require a range of construction techniques. In general, modular is better. Mobile garages with truss systems and very little locked-down foundation would provide “good to go anywhere” shelter, protecting vehicles and construction materials from dust contamination. Other useful base modules include cargo containers, manufacturing hangars, STNs (Six-way Transition Nodes), FTNs (Four-way Transition Nodes, and HALSIPHs (Horizontal Axis Linear Surface Inflatable Pop-out Habitat) - single-story structures with pop-out modules and airlocks on both ends. The cylindrical HALSIPH modules resemble an Airstream camper, with a small kitchen and restrooms.
Early rough sketch of four STNs (each with three skylights) linking four HALSIPHs to a mobile garage (bottom) and four construction hangars (left).
The latest “space matrix” combines various modules to create a Gen-II settlement that houses over 1000 people. The settlement is bootstrapped from a Gen-I settlement using portable trailers (HALSIPHs) for initial worker residence. The matrix currently exists only as a schematic… artistic drawings are forthcoming.
A “lifeboat” strategy might replace the internal “ladder structure” of the Gen-I settlement. If primary Transition Nodes connecting various modules fail (fire, depressurization, etc), settlers would use portable HALSIPHs or pressurized rovers as temporary survival shelters. Obviously this approach requires access to the surface. The ladder structure or a ring/loop design might still prove useful in the sections of the settlement that are buried under meters of regolith.
The Gen-II settlement needs about 200 square meters of periodically pressurized manufacturing areas, and 10,000 square meters of unpressurized manufacturing areas. The unpressurized areas may be left open or covered in places by a simple tent-like material to minimize dust contamination, as would be done in dusty environments on Earth.
The Gen-II architecture requires more development and better visualization. Artistic drawings would help, but the critical issues of survivability and redundancy (above) might force a general redesign. We also need a clear delineation between buried modules and sections that are open to the surface. Other open questions include the orientation of the permanent habitats and power generation facilities. The goal for the overall habitable floor-plan area remains 5000 square-meters (with an appropriate cubic-meter volume equivalent).
Minerals and Mining, 101
Vernon Kramer’s presentation on mining strategies relied upon “ground truth” information from the Opportunity rover, coupled with data from several spacecraft in Mars orbit – a powerful combination that validates the decision to move the settlement from Chandor Chasma to Terra Meridiani.
However, in terms of data necessary for efficient mining operations, the Opportunity rover has barely begun to scratch the surface (literally). The rover has offered tantalizing hints about mineral compositions, but a full site survey is required before full-scale mining operations could begin. Orbiters and rovers cannot conduct an adequate survey; we need experienced human geologists on the ground with maximum mobility, in-situ analysis equipment, and the ability to gather precise core samples and react to serendipitous findings.
Vernon’s detailed list of “mining needs” contains the following:
A. A dedicated (several years) Meridiani Exploration Vehicle (MEV) – an exploration vehicle dedicated to exploring for “economic concentrations” of minerals such as: hematite spherules – hydrated minerals (jarosite – kieserite and hopefully gypsum) – plagioclase – clay - olivine, etc. at distances of hundreds of kilometers from the immediate community area.
B. A dedicated crew of 2 exploration mining-geologists to discover and delineate “economic deposits” of our required resources.
C. An MEV and two mining exploration geologists capable of traveling over minimally rough terrains for several hundred kilometers, many days away from the community site (rarely traveling in straight lines). We assume that we will be able to plot our vehicular courses (Mars-GPS?) and can communicate at all times with the community site. The vehicle must provide “isolated” living conditions for a few days at a time, and it must allow multiple human entries and exits from the vehicle to collect and store samples (up to several 100 kg of samples per commodity).
D. Vehicle equipment, including a microscope, cameras, scales, magnetometer (metal detector), equipment to hand-crush samples, screens for separation and sizing, magnets, rock hammers, sledge hammers, chisels, rakes, a small rock saw, a small metal saw, large cloth or plastic bags (several hundred) to collect enough weight of samples to test production methods at the base, etc.
E. Human-enabled “ground truth.” Unfortunately, finding the acceptable, economical mining sites and transportation routes from the mining area to the community processing plants cannot be done “in a timely manner” from space nor by robots (existing or planned).
F. A small, mobile MEV. The MEV would not be “a home or office for the mining outpost.” That type of vehicle would be too big for exploration. Once there is enough work to establish a final mining site for one commodity, the MEV would be available for further exploration of other commodities.
G. At least one rescue vehicle at the home base capable of driving long distances to retrieve or repair a stranded exploration vehicle.
H. Crew living quarters at the home settlement that will be vacant for days at a time.
I. A pressurized “garage” at the home settlement for maintaining vehicles that have been subjected to the harshest terrains and re-outfitting the vehicles for the next outing.
The Terra Meridiani base site is situated between two large craters, about 50 km apart. The surrounding terrain is fairly flat, but not as flat as one would assume from the Opportunity travels and images. 10 cm rocks are common, with occasional, larger boulders – probably ejecta from the impact craters.
Mineral Mining Exploration Sites near the 4FC settlement (dark blue square). Yellow square is the Opportunity rover landing site. Triangles indicate possible high-priority mining sites. Axes are 100 kilometers in length (Click image for larger view).
This region probably contains a 5% by-weight water density of hydrated minerals. However, the depth of hydration is largely unknown. Surface concentrations, perhaps a coating on the blowing sands, could be high enough to fool us into thinking that ample deposits exist below, yet shallow enough to be nearly useless for mining operations. Therefore, orbiter data cannot be trusted entirely. Hydrated bedrock would allow efficient mining operations; reaching and analyzing the bedrock is critical.
Opportunity rover image of Burn's Formation, which contains jarosite, kieserite, and likely gypsum deposits within the bedrock (Click image for larger view).
Other important resources include basalt, feldspar, high-silica clays, quartz, and chalcopyrite. Data suggests the presence of chalcopyrite, a copper sulfate, but the conclusion is uncertain because chalcopyrite is not found in this type of mineral environment on the Earth. The Opportunity rover has not found any quartz deposits yet, making quartz a good future exploration goal.
We can collect hematite nodules using relatively simple scraping techniques, but collecting other minerals will require drilling and blasting. If the settlement requires 57 tonnes of iron for Gen-II module construction, we could meet the goal by mining iron from hematite in about 250 sols.
Water, Water Everywhere...
Michael Busch presented an in-depth (no pun intended) study of water sources near the Terra Meridiani base site. Ice, water aquifers, and hydrated minerals are the three main places for water to hide on Mars. Estimates of equatorial water and ice depth vary widely, but a conservative estimate places pure ice deposits at least 1 km below the surface, with water aquifers 10’s of km deep. A Gen-II mining team has no known, practical way of reaching these depths. The presence of near-surface deposits of ice, perhaps in cold-traps like lava tubes, cannot be assumed within this study until teams of ground explorers verify and survey them.
Fortunately, as was noted in the section on mining and resources, our only on-the-ground geologist (Opportunity) has verified the presence and accessibility of hydrated minerals. Gypsum seems an especially useful resource because it will release its water content when baked at fairly low temperatures. The overall water content in this region should be at least 5% by-weight, with a 3x variation, i.e. some local deposits could be 15% water by-weight.
Martian hydrated minerals should release their water content when baked at relatively low temperatures (~200C) in a pressure vessel for about two hours. The operation requires some equipment (furnace, condensers, plumbing, rock crusher, slag removal, transport vehicles), raw materials, and thermal energy (resistance heating), plus a small amount of methane/oxygen fuel to power the transport vehicles. The 4 to 5 kilowatts of thermal energy per-kilogram of crushed rock probably won’t come from nuclear heat, unless a reactor was positioned at the mining site. Shipping the energy to the site as electricity would be far simpler and safer.
We took a well-deserved break for lunch at about 12:00 – sandwiches, pasta, and plenty of sides – and reconvened for the afternoon session at 1:00. During this break, we also ventured outside to enjoy the mild winter day and take a group photo. Light morning showers brought the colors to life, giving way to a beautiful Georgian afternoon.
Our group spent the afternoon indoors, however. Though we had tackled some difficult topics in the morning, the agenda for the afternoon session promised even more Martian thrills and spills, including presentations on refining and manufacturing processes, energy, transportation, EDL (entry, descent, & landing), greenhouses, aquaculture, human-factors, and spacesuits. These and other topics, including the best place to dine on a Saturday night in Atlanta, will be discussed in Part 2 of the Gen-II update for the second Atlanta workshop. Stay tuned!