Analysis of the ESA/Hassel Lunar Base

Earlier last month Hassel in collaboration with ESA published a concept of a Lunar base set for long-term sustainability. As that is absolutely “my thing” I have waited for additional information to trickle through the grapevine before writing up my Opinion. There were certain stages in which my opinion shifted and formed. My first impression was that it was just another unrealistic stunt, that feeling was stirred due to some of the interior pictures of large pointless, and for the lunar environment ergonomically unsuitable lounges. That feeling implied that other concepts are similarly less carefully thought out.

Then I got into it a bit more and the concept took shape. Things such as radiation shielding and expansion are basic design concepts. There is a very strong focus on enabling research and science and there even is a possibility for select companies to set up their own work small spaces.

As is, at this point i thought the concept represents a good, realistic and well-considered medium-sized surface base concept.

Then, however, there was the third feeling, and that one concerns itself with costs, logistics and longevity of such a project. In this regard the concept does not convince and stands in stark contrast to the underground large scale proposal that focuses on industrial capacity I made a while back.

But lets first dive into some of the critical aspects of how the Hassel base fares.

Radiation: First and foremost a surface base needs to have this topic on lockdown. Location plays an extraordinary role in this as the base concept is very likely for the polar regions direct solar radiation is going to be less of a concern however, not by much. Incidence onto their base is sideways. However, the design which uses mounds of regolith where modules are half buried are covered with what it seem like giant caltrops. These are I presume sintered from regolith and then stacked upon each other to provide a sturdy cover. Their stability and strength is likely going to be fine, but the gaps in between these caltrops may not provide adequate and reliable protection at all times. Furthermore, the walkways that connect the various modules are unprotected by what appears to be inflatable tubes hanging above the surface of the base. While it's unlikely that people will spend a long time in them, the short time they do spend there unprotected will slowly add towards accumulated radiation dose and means that personnel living there are not expected to stay there for long periods (months or years) and continuous rotation is necessary or that permanent occupation is not something the designers have thought of. All in all, its a relatively safe design for medium durations.

Effort of construction: This base design requires an enormous amount of launches to start even initial construction. Excavators and other heavy Earthmovers have to be brought to the surface to dig out trenches and collect material for sintering of the shielding caltrops (more on that later..). This will require the use of a nuclear power source. Solar power can be considered if the entire construction effort is automated. However, we are not able to provide this level of automation reliably for the foreseeable future. As such a Nuclear reactor will have to provide power, which also makes the addition of the solar panels redundant as reasonably the reactor can continue to be used to power the base. The sintering apparatus itself requires enormous amounts of power, the different heavy machines also want to be charged, the people working there need to be protected from radiation and all building materials (for the shells) need to be flown in from Earth. After the construction is done. The excavators could be rebuilt and serve as multipurpose rovers. All in all, a big initial investment is necessary to lay the foundation. Continued expansion is far easier, as most of the machines are already on site, but the shells of the living spaces themselves still need to be brought from Earth.

Long term sustainability: Here we catch a few snags. The Hassel base template does not allow for large-scale hydro/fog-ponic agriculture or heavy industry installations. Small labs within the small apartment-sized modules mean that it is primarily geared towards research and perhaps ultra high-end tourism. Research in particular is not a sustainable business model for expansion of the base and a shift into heavy industry is hampered by the base’s template. While some revenue can be generated from renting out space, or creating dedicated modules. It does not stand in any relation to the expenses for initial construction or continued operation and will likely never break even. While much important research needs to be done. All that can be done in that location, will eventually be done. This is all the more important if the water deposits in the shadowed regions of the pole craters turn out to not be as rich as expected. Or that water is abundant in many regions below the surface of the moon. In either case, the base will likely never be profitable and eventually has to be abandoned when larger-scale lunar operations become available.

The Caltrops: While they seem like a good idea, here we run into one of the few very problematic parts of the project. While I rendered the picture you all clicked on to get to this article, I needed several thousand of them to cover one of the domes. This is a big problem as making them in a timely manner is in my opinion not realistic. To make them, regolith has to be collected (the easy part), preprocessed, eventually crushed and then put into a furnace to sinter. Generally speaking, a temperature of around 950°C is necessary and held for around 1-2 hours. If we are being incredibly generous we can say that they can do all of this in 2 hours per caltrop (likely it will take longer). This will require around ~50kw/h of power, if we can run 10 of them at once, its 500kw/h or almost a third of my yearly power consumption here on Earth. But even if we have an incredibly large and incredibly powerhungry furnace that requires to be fed by almost a quarter of a megawatt constantly. Its being run 24/7 without any interuption, producing 120 of them a day. One habitat can be covered after 1-2 months. In reality production is likely slower and interuptions will be normal. But even if we can make it, the manpower, electrical power and infrastructure/machinery required to pull it off in a timely manner will require a relatively large base on its own to house the dozens of workers and engineers necessary. I would suggest to just use regolith to cover it, there no downsides to doing that, as the habitat modules themselves should be able to resist the pressure. Which, again...isnt a lot as the lunar gravity makes it 1/6th of what it would be on earth. With the benefit that there wont be empty space , increasing the protection. (To be fair: Hassel is a bit unclear on how the caltrops are made, I believe its sintering as 3D printing these many would require an oil tanker worth of binder. Which I don’t think is practical.)

Ergonomics and quality of life: For medium to longterm habitation, the comfort of living and working there also needs to be considered. While not vital, there are a few things that I have noticed immediately that may not be instantly obvious to us folks from Earth. Or even people who have spent time in space. The biggest influencer is gravity. The gravity is low enough to make normal movement like we do here down on earth not possible. Everything is going to be slightly different and that does not mean that it is going to be terrible. Quite the opposite, its likely quite wonderful if the indigenous characteristics of this environment are taken into account and embraced. The wonderfully cool picture of a lounge-looking type of area, with soft cushy chairs, open space, low tables hanging lamps and large windows looks slick as slick can be. It is sadly almost guaranteed to infuriate people living there for longer than a day. Walking, is not like we do it here on Earth. The hopping we know from Apollo astronauts was largely due to the stiff and restrictive vac suits. Walking on the moon will involve pushing yourself off and gliding in long elegant strides towards wherever you want to go. It will be hard turning sharp corners and you almost always need things to push you off to gain that horizontal velocity. Low ceilings will literally cause headaches as railings or poles are absent, a person getting up from the cushy chair will do so haphazardly as they have no 3rd point of contact. So what will end up happening is people pushing themselves off the ground, to reach the ceiling to push themselves down and forward again. Zigzagging up and down to leave this uncomfortable place. The lamps, are likely the first victims of the inevitable accidents. The large windows are also ultimately unnecessary as the only sight they see are the caltrops covering the module. The small inflatable tubes will likely be incredibly awkward to move around as there isn't enough space to allow for natural movement. The entire interior design is ill suited for the lunar environment. Any Lunar design requires ceilings of at least 3,5 meters height to ensure that even a strong stride will not cause a head injury. It looks good, but in the same way that AI art looks good. Its pleasant but without much thought.

While I have my own skin in the game with my proposal for Lunar construction, the two are hardly comparable as their approaches are very different. While mine is a large scale underground base, primarily build to enable commercial and heavy industry, a strong focus on in-situ resource utilization and permanent habitation. It hinges upon the confirmation of water ice deposits under the surface of the moon. The Hassel concept bases their viability on the polar ice deposits. But can even work without any sort of In situ resource utilization. This means that constant supply from Earth is necessary. All in all it is a good concept, with few glaring quality of life and feasibility issues. Solar power, as prominently displayed is likely not going to be practical except if the very much necessary nuclear reactor does not produce enough power. Which is unlikely as the power requirements to create the base in the first place are so high, it should be able to power even a heavily expanded base for longer than the base is designed for. Which brings me to an important point. While it is the most advanced surface lunar base design. It is not going to enable humanity to live on the Moon. It will enable a few select scientists to do some important experiments. Similar to the ISS. Which brings me back to my intro. When I first heard of it I was skeptical. Then I learned more and was excited, but then I sat down and thought about it. And after thinking about it long and hard, I don’t think it is a viable design.

We can do very small (Artemis) or we can do very large (my underground approach/the Chinese one) on the moon. A medium approach is doomed because it can do slightly more than a small base can, while costing slightly less than a large-scale base in construction and upkeep.

I hope this was a fair assessment of this project, it didnt take a long time to write, but it took me quite a long time to get started because i didnt want to write a negative article. I want to champion and support any European effort in regards to space and the moon. The people involved seem to be genuine nerds like me and they had perhaps more than just one rainy afternoon to render their images...fair enough my dayjob keeps me quite busy and sadly far away from my hobby. Still this article does have a heavy negative tone and i decided to publish it nonetheless because there are some details that make the proposal not very realistic. Can it be done? Yes! Should it be? Perhaps not in this form.