In the previous posting, we looked at the basic aspects of constructing a permanent sustainable moonbase, and the reasons for such a base. Now let's give some thought to how such a base would be designed, and the question of how we would go about actually building it.
Over the years, science fiction illustrators have happily drawn countless variations on the concept of a domed Moon city and there's a certain logic to the idea: the idea scales well, from small to large, air pressure holds the dome up, it would be relatively easy to transport, and relatively easy to erect. However, the down side of the dome is its relative fragility - on Earth, having a 20 pound chunk of metallic meteor punch through the roof is newsworthy. On the Moon, it would be fatal.
It makes more sense to create a modular system, something that will require more time to put together, but which will be safer and more practical in the long run. Modularity is a good thing - if there's a blowout in one module for whatever reason, you can hopefully seal off that module and maintain the integrity of the remainder of your habitat.
One option is to design some kind of standardized unit, a combination of cargo container and pre-fab housing, so that once they were landed on the Moon and emptied of supplies, they could be daisy-chained together with access corridors or air locks to create a sort of temporary trailer park. As work went on, the modules could disconnected one at a time and buried or covered to provide protection from solar radiation.
NASA seems to be thinking more in terms of on-site construction, based on the concept of In Situ Resource Utilization, or ISRU, for short. Research has been done into using lunar dust as a building material, a sort of moon concrete, possibly using sulphur* rather than water as a binding agent. The resulting material would be used to build walls and foundations using a process like 3-D printing.
However, there are two very practical aspects of this process that have nothing to do with the design of the base, and everything to do with the actual process of building it: personnel and resources.
Until now, space travel has been a game of elites, with two or three astronauts at a time being trained and then dispatched into space. But the practicalities of building a Moon base would require dozens if not hundreds of people, people who will need to be transported to the lunar surface, where they will require spacesuits suited for the rigors of construction. They will need a place to live while they build a place to live. They will need food, water and oxygen, not to mention tools and materials. They will need training so that they can perform their duties in an environment that will punish mistakes with death, and they will need to create an entirely new building process as they go.
Is this excessive? Do we really need more people than the standard three-person NASA crew to build our base on the Moon? That depends - what's our timeline for completion? For that matter, what's our baseline? How long does it take to build things on Earth?
In 1930, it took 3,400 people 410 days to build the Empire State Building, which is apparently very fast for a structure of that magnitude. However, we're probably a long way away from skyscrapers on the Moon. At the other end of the spectrum, it takes between three and six months to build a standard home, although the internet suggests timelines as long as 16 months for a custom structure - in other words, longer than the Empire State Building, but let's be fair, you're looking at a lot less than 3,400 workers.
Regardless, both of those examples are being built in an oxygen atmosphere, with standard gravity, and everything you could possibly need no further away than the closest Home Depot. It also involves cranes, fork lifts, excavators, and bulldozers, and a specialized labour force of welders, masons, framers, dry wallers, roofers, plumbers and electricians working on it - not to mention painters, tile setters and cabinet makers.
The International Space Station is probably a better example. The ISS is made up of 16 modules: nine American, four Russian, two Japanese, and one European, with a Soyuz attached for use as a lifeboat. Construction on the ISS started in 1998, with the launch of the American Zarya module. Forty missions, 36 of which were Space Shuttle launches, were required to put all of the station's elements into orbit, with a two and a half year hiatus after the Columbia disaster in 2003. The final element was added in 2016, adding up to an 18-year construction program.**
What's the equivalent timeline for a base on the moon? It only takes eight or nine minutes to get into orbit, as opposed to the three-day trip to the Moon, and I haven't seen any evidence of a planned equivalent to the Space Shuttle that will be able to act as a heavy lift cargo transporter. (The cancelled Obama-era Constellation program included plans for a heavy-lift cargo module, the Altair, which would have been capable of transporting six tons of cargo and four astronauts to the Moon's surface - NASA might want to look at pulling those specifications out of storage.)
The astronauts assembling the ISS also had the advantage of zero gravity, and tools like the Canadarm that streamlined the process.
Logic says that in the case of a lunar base, it will have to rely on prefabricated building elements of some sort, but even then, it will require some kind of heavy equipment on the Moon in order to create foundations, dig holes, and move the pieces into place. The alternative is, of course, smaller pieces, but the smaller the pieces the more assembly and connection is required, and we're back to our crew of specialists.
The bottom line is that NASA actually has complete control over the timeline. If the US government supports it, they have the expertise to create the necessary tools and processes, and there will be a significant base on the Moon by the planned date of 2028. But really, NASA doesn't need to do any of this to meet that target. They could just drop the equivalent of a Airstream trailer onto the Moon's surface, and voilà, we have a permanent Moon base, done. But is that really enough? Could this be the moment that history will look back upon as the real beginning of our expansion from Earth into the solar system?
For a long time, NASA was as much a political tool as anything else, but over time it's evolved into the scientific enterprise that it should always have been. Now it's time to apply the results of its research to the practical aspects of man living in space. The next step in their evolution is here: let's hope that they - and the government that supports them - are up to the task.
The first generation of astronauts was made up of risk takers: test pilots, ex-military fliers, people whose experience lay in performing in life-threatening situations. The second generation needed scientists, people who could perform experiments and conduct research.
The third generation will need to change again. Creating a permanent presence on the Moon will require builders: engineers, geologists, safety specialists, construction experts, people who can pave the way for the permanent residents of the fourth generation: the colonists.
- Sid
* No, seriously, this is an actual thing:
Now
you know what they did with those samples that the Apollo astronauts
collected from the surface of the Moon, although in some cases
experiments have been conducted with moon soil "simulants" based on
analysis of actual moon dust, rather than the real thing.
** There are still a couple of planned modules to be added, and eight other modules were cancelled, but the station is obviously in operation in its current configuration.
** There are still a couple of planned modules to be added, and eight other modules were cancelled, but the station is obviously in operation in its current configuration.
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