Or, basic surface infrastructure for the Moon and Mars.
I’ve written a few blogs about space stuff over the last couple of years but I’m not yet out of ideas. The usual disclaimers apply.
As of May 2021, it looks like SpaceX has a reasonably solid lead in launch. This isn’t preordained to last forever, especially as copying a finalized Starship will be much easier for competitors, liberally salted with former SpaceX employees, than getting the design right in the first place.
In the mean time, however, there are plenty of other worthy problems now that deep space transport seems, at last, to be on the glide slope. Simply put, Starships exist to build cities on Mars, the Moon, and maybe even space stations. There is more to building a city on Mars than showing up with a million tonnes of cargo and unpacking. Inside the base, an overwhelmingly enormous pressurized and climate-controlled environment enables deployment of commercial off the shelf (COTS) and COTS-adjacent hardware for doing any number of things: manufacturing, agriculture, energy, refining, computing, habitation.
Building a large shirt-sleeves environment for “doing stuff” is non-trivial. Without Starship, spending effort on solving these problems is a bit premature. With Starship, SpaceX or someone will have to solve these problems. So what are the problems?
The idea is to get a bit more granular than usual here, and to map out what is needed, who will provide it, and how they will interface with the existing space knowledgebase as curated by NASA and others.
Basic subsystems for Mars
The following nine technologies exist in varying levels of maturity or applicability, but all need to be rapidly improved to enable construction of cities on Mars. Large Moon bases also need a subset of these capabilities, depending on the degree of ambition harbored for independent Lunar industrial capacity.
Each of these technologies needs a rigorous development and test program in, ideally, large vacuum chambers here on Earth. Built on existing environmental testing performed for deep space robots, shake/bake/vibe/radiation/abrasion/vacuum testing can hew to a set of evolving standards designed to help existing commercial companies adapt existing designs to operate reliably in space with relatively little additional development cost.
- Solar farm.
- Air miner (CO2, nitrogen, H2O).
- Water miner (Rodwell? Geothermal artesian source?).
- Rock miner(s) (aggregate and ore).
- Fuel plant (CH4 + O2 in unlimited quantities).
- Life support (interior air miner).
- Heavy machinery telerobotics.
- Pressure structures. Pressure tents (manufacturing, deployment, maintenance).
- Surface activity suits.
Interior COTS subsystems
In addition to the nine core technologies that intermediate the interface between squishy human terraria and the cold harsh pitiless vacuum of space, lower intensity but larger volume development will be needed to adapt COTS systems to operate inside the Mars base, which is intended to swiftly become a gigantic metafactory that reproduces the entire industrial stack.
While machinery on the interior, given a sufficiently sophisticated pressurized supply chain, doesn’t have to endure vacuum, big thermal cycles, corrosive Mars dirt, or as much ionizing radiation, it does have to operate safely and reliably in what amounts to a confined space with a severe labor shortage. A parallel set of guidelines and standards will evolve to ensure that Earth-designed machinery can operate despite the lower gravity on Mars, which is just 38% of Earth’s.
Lower gravity can have a surprising range of effects. For example, lower gravity affects friction, fluid flow, convection, gravitational preloading, damping, vibration modes, pendulums, and the angle of repose of materials.
At the most basic level, machinery with the Mars base is concerned with performing primarily chemical transformations of matter between different forms. In more detail, specific plants will have to be set up to do:
- Chemical synthesis (plastics, lubricants, fertilizers, drugs, adhesives, fuels, …)
- Fundamental research
- Metal refining
- Fabricated metal
- Forestry (why not!)
For the remainder of this post I’m going to focus on the major new verticals as opportunities for potential new entrants to quickly add value to the overall endeavor.
Who are SpaceX’s Natural Industrial Partners
I don’t think any of the nine core technology areas are beyond SpaceX’s capacity, given enough time. But I am equally certain that, given the option, SpaceX would rather become part of a much broader industrial coalition oriented towards providing all the necessary stuff rather than have to do it all themselves.
There are good reasons for other companies to get involved. Branding rights and prestige are obvious benefits. Marketing and business development. If you’re the best in the business, prove it by showing you have what it takes to do it in space. Recruitment is greatly helped by having prominent flagship projects that attract a steady stream of top engineers, whether fresh out of school or bringing decades of experience.
Most importantly, if they don’t come to the table with the system SpaceX needs for the Mars city, they run the risk that SpaceX will build it themselves, verticalize in their industry, and rapidly automate them out of existence.
Starship’s generous cargo capacity means that existing industrial machinery does not need the usual space treatment of being rebuilt from paper-thin titanium to be light enough. Instead, engineering effort can be focused on reliability and production.
In this section, I’m going to provide some examples of companies, mostly local to Los Angeles or the US, which do this sort of work. The list is by no means exclusive or exhaustive, and if your company is working on this stuff I am always interested to hear about it.
1. Solar farm.
Solar panels will be one of the first systems to be locally produced. During importation, emphasis is on high efficiency and low mass, which means cutting edge space-rated solar panels such as the ones by Deployable Space Systems being added to the ISS later this year.
Locally manufactured panels care less about weight and efficiency, and more about manufacturability. At scale, expertise is needed for system integration and installation. 8 Minute Energy has a few gigawatts of capacity in the pipeline, and this is roughly the scale needed to do seriously interesting stuff on Mars.
2. Air miners.
Mars’ atmosphere is thin, cold, and poisonous, but does provide an inexhaustible local supply of CO2, nitrogen, and water vapor. The Mars city will need large scale air mining systems that do what MOXIE does, but about six orders of magnitude more of it. Over and above what such systems already do on Earth, Mars’ atmosphere is thin enough that the first stage compressor (probably a scroll pump) must operate upstream of any kind of filtration, so has to be robust enough to handle airborne dust.
There are numerous companies that perform air handling and liquification and separation. Trane is one of the larger US manufacturers of industrial scale air conditioning systems, while Praxair used to routinely service the liquid nitrogen machines at Caltech.
Existing industrial knowledge in this space is already relatively close to a useful system for Mars applications, especially as there is little design heritage (compared to, say, space suits) at NASA for these kinds of applications.
3. Water miners.
Extracting water vapor from the Mars atmosphere is better than nothing, but ultimately a Mars city is going to need simply enormous quantities of water to do anything. Per capita usage in the US is around 200 kg/day, and there is every reason to suspect that per capita productivity, and thus consumption, would be substantially higher on Mars.
So we’re going to need a well. Relatively pure ice deposits can be mined using a thermal Rodwell. Hot water is circulated through a well drilled into the ice deposit, melting more water that can be continually extracted from a bulb that sinks further into the ice. Even better, a Mars city could be located over a geothermally heated artesian water source.
Expertise to create Rodwells exists within the US Antarctic Program, and they’ve also been applied by the Navy as part of Project Iceworm. There is no shortage of sophisticated drilling expertise in the US. It only remains for one or more of these entities to qualify their process for Mars surface ops and make it both robust and largely automated.
4. Rock miners.
No matter how lucky we get with city siting, a mature industrial base will have a need for a very diverse range of minerals, requiring the operation of remote mining facilities. Rio Tinto, among others, have pioneered fully automated mines (not to mention the fully automated destruction of world heritage cultural sites) in Western Australia, a place so inhospitable that humans have lost not one, but two wars against a band of militant emus. Some of my ancestors also spent a few generations getting hopelessly lost in the region, as compasses are affected by iron ore deposits.
More seriously, robust, mostly automated mechanisms to locate and extract aggregate and ore are needed. If fully pressurized operations are needed, mine sites could be enclosed in pressurized ceilings or build behind hard rock tunnel boring machines. More probably, near surface deposits of all kinds of interesting stuff are lying around due to a) constant bombardment by iron-rich meteorites and b) no prior generations of miners getting all the easy stuff. Prospecting is needed!
5. Fuel plant.
Starships need 960 T of O2 and 240 T of CH4 to return to Earth. While most Starships carrying cargo will probably make one way trips, as it’s easier to make a new Starship in the factory than pay to get a used one back from Mars, substantial return capacity will be needed for people who want to return to Earth. The per capita fuel requirement to fly back to Earth makes even weekly commutes by Concorde look reasonable by comparison.
The fuel plant will not be drilling for oil and gas on Mars. Instead, it will be synthesizing hydrocarbons from water and CO2, using copious quantities of electricity from the afore mentioned expansive solar plants. Hydrocarbons are also essential industrial feedstocks for chemicals, plastics, heat, and a thousand other things. While tabletop demonstrators of this technology have been around for long time, the space-ready automated production of a fuel plant at the desired scale is a new opportunity for a couple of reasons.
First, existing high throughput hydrocarbon companies who normally run refineries have an opportunity to apply their skills and knowledge to a different kind of problem.
Second, becoming the world(s) expert on synthesizing near-infinite quantities of methane is an enormously important technology for transitioning industry away from fossil fuels this decade. I think by 2026 it will be cheaper to make methane from solar electricity than to make electricity by burning gas, which represents a substantial business opportunity, to say the least. Prometheus fuels is the first business that I’m aware of in this space, but there’s no reason that Pioneer Astronautics couldn’t also jump in.
6. Life support.
Keeping humans alive in a confined space has substantial design heritage in both space and submarines. Yet doing at the necessary scale and with the available resources represents a new kind of challenge. The ECLSS system on the ISS is too labor intensive to be useful on Mars. We need something cheaper, faster, and better.
The air refreshment part of life support is conceptually very similar to the air miners discussed earlier, only specializing in extracting CO2 and H2O vapor, monitoring and removing trace gas contaminants, and watching for leaks. Life support also covers thermal management and fire suppression.
SpaceX already has functional ECLSS on the Dragon spacecraft, but the life support systems needed for deep space transport look a bit different to systems for a city on the surface. In particular, the city will have the ability to extract water, oxygen, and nitrogen from the Martian atmosphere so can trade complexity for reliability.
7. Telerobotic heavy machinery.
A Mars city with a huge local industry is going to need a lot of wheeled vehicles for transporting materials and tools. This includes electric vehicles for operation within the city, and a wide variety of robust machines for operating outside the pressure hull.
Hydraulically operated heavy machinery is already well adapted to operating in the near-vacuum of Mars. It will need modifications to survive low temperatures, low pressure, low maintenance availability, tele-operation, and the use of space-capable hydraulic powerpacks.
A group of interested companies should invest in an environmental test chamber and work out what tweaks are needed on the production line to get their machinery onto a Starship at Boca Chica and out onto the Martian Planitia. Caterpillar already spends ~$2b a year on R&D, and are probably the team to beat here.
8. Pressure structures.
Space stations, Moon bases, and Mars cities need pressurized volumes in which to live, work, and build. While the ISS was built mostly of pressurized cans from Alenia, a Mars city will need millions of cubic meters of volume, and so some kind of inflatable tensile structure seems like the way to go.
On Earth, pressurized tensile structures are routinely used for everything from car tires to inflatable mattresses, Zodiac dinghies, planes, and sheltered sports venues. Traditionally Goodyear would have been the company to watch, with their aggressive R&D and expertise in rubbers. But since they stopped building rigid airships, I just don’t know.
DuPont’s IP and expertise with fluorinated plastics such as Tefzel is an enviable position from which to approach this problem. Could they build a giant transparent multi-layer inflatable space station? The ultimate bounce house? Can 3M help?
Finally, yacht racing sails are also high performance tensile structures that can be made transparent and have to endure tough conditions. My ultimate picks would include a small contingent of sail engineers fresh off the latest Americas Cup.
Pressure structures for deep space or the lunar surface have a different set of requirements, but still represent a worthy problem in value engineering. In particular, finding a way to build and launch an ISS-like space station for ~$100m is probably necessary to approach commercial viability. A 1000 fold reduction in cost will require aggressive value maximization, including in pressure structures. Milling each hull panel from a 10 T chunk of aluminium we will not!
9. Surface Activity Suits.
Finally, there will be times when humans must endure the danger, discomfort, and inconvenience of operating outside the city or a pressurized rover. For this, they will need a suit that can protect them from the low temperatures and pressures of the Mars surface.
The environment and activity spectrum of the Mars surface is different enough from LEO that the Mars surface activity suits will look and function very differently to suits currently used on the ISS. In particular, Mars suits won’t need micrometeoroid protection, but they will need to be resistant to abrasion. They won’t need rocket packs but they will need to enable enough mobility to be useful.
In science fiction, such as The Martian or The Mars Trilogy, surface activity suits are usually depicted as highly capable, versatile garments only one or two increments more difficult to use than a thick parka. This could be the case for the Mars city, but such a suit is yet to be invented or tested.
I’ve always liked the idea of a mechanical pressure suit, with an Antarctica-like Carhartts and parka to go over the top for thermal regulation and pockets. Building one (or hundreds) that support any body type, activity, duration of vacuum exposure, and quick don/doff is an unsolved problem. I think something like a pneumatic windlass, similar to early g-suits, could help. But I have no personal expertise in this area, and freely concede that we’ll probably have to deal with gas pressure suits.
Even the space suits to be used for Artemis are currently uncertain. NASA has asked for $200m in the next budget to pursue a private public partnership for suit development, much like the process that let ILC build the original Apollo Moon suits and supported SpaceX’s Dragon development.
Spacesuit design can be relatively easily tested and iterated due to the relatively low masses and technical lock in required. I look forward to seeing rapid innovation in this area.
Low Value Opportunities
I’m not convinced that space based solar power or asteroid mining is a worthwhile endeavor. Self replicating robots (otherwise known as inorganic biotech?) would be awesome but are probably very tough to do.
We’ve outlined nine core technologies needed to turbocharge Mars city construction. We’ve surveyed a selection of existing companies and processes relevant to these technologies. Some of the technologies are more niche than others. Some represent enormous standalone business opportunities.
In May 2021, TRL 9 solutions exist for every remaining technical problem faced by Starship. No suspension of the laws of physics is required to build a fully and rapidly reusable Mars city transport machine, though ultimately I expect Starship to be somewhat more elegant than a mere concatenation of SN15 and already existing technical solutions.
It is time to think about the next challenge. Which subsystems of the Mars city do you want to work on? Which ones will you insist SpaceX integrate into their plan? Which companies are coming along for the ride? Which will be left behind? Even within NASA, how can existing competencies be aligned with a drastic shift in launch availability and system design philosophy?