Report: Solutions for Construction of a Lunar Base (Starship as base structure)

[SkyRate]

For radiation protection, land or park the vertical ships in a ring, run a superconducting cable around that ring (at some to-be-determined optimum altitude) and power it. Now you have a torus-shaped magnetosphere. Essentially an inside-out van Allen belt.

[volker2020]

Three of my key principles are being violated here:

1) Keep it simple
2) Do as much work as you can on Earth where labour is orders of magnitude cheaper.
3) Proportionate consideration of risk.

Outfit your base on Earth in the gigantic fairing volume. If the stack is too wobbly to move, and/or the cargo lift is too much of a pain to use then get a big crane (you’ll probably want one anyway) and detach the nose section.

With regards to radiation exposure the expected unmitigated doses of around 0.5 Gy per year are high, but well within NASA career limits. Burying everything under 5m of regolith sounds good, but you’d need to do it all with remote controlled diggers to get an actual reduction in astronaut risk as EVA is a high risk activity. I’d expect to see localised shielding in high occupancy areas to control doses, rather than major civil engineering or spacecraft modifications as such measures are likely to be at best grossly disproportionate.

Keep it simple sounds good, than you have no access to that gigantic fairing volume on moon. If you want to move this station out, in one go, you need equally big doors. The method they want to use in orbit won't cut it on moon, because you need a way to stabilize the ship, when the center of gravity changes, or remove the complete nose, even when you have this very large crane (which by itself would be quite a complex piece of hardware).
2 winches sound rather straight forward compared to this.

ps. 80cm of regolith should do the trick, according to the paper referenced above.
pps. The horizontal station that is within the nose, could be finished on earth. (and would by definition be equally big). The part that might become harder, is using the tank area as additional storage. But in a direct comparison, that should be regarded an extra option.

No need to extract the habitat through doors; the fairing is the habitat.

There is nothing straightforward about conducting a controlled topple of a gigantic steel cylinder using winches and with workers in spacesuits. A crane is significantly simpler, and can be used for a range of other lifting operations.

I guess we agree to disagree. If the fairing is the habitat, you need a way to decouple those 2, which in my books would end up a rather complex problem.

To construct a crane capable of lifting ~20T with a height of at least 50m, would in itself be a major task. What do you think
how many separate modules would you need (you have to bring them down using the lift).

Using winches to topple a high object is old news even for the old Egyptians, and once you fixated the 2 or 3 winches and the hinge, there is not much human interaction needed.   

[Alberto-Girardi]

A lightbulb has turned on in my head. Employing Starship in horizontal position on another planet is a bad idea for a very good but non-engineering reason: It has become symbolic.

Most of us that follow SS development believe that SS will eventually be successful. It will land people on Mars; It will begin colonization of Mars: it will make possible our exploration of Europa, Titan, Eceladus, and further into the Solar  System and beyond.

In a nutshell:
Starship has become the symbol for Mankind’s entry into the Galaxy.

For this reason:
Starship, I salute thee. I shall never again suggest that you should lie supine on any planet.

Interesting phylosphical thought, but I could turn this around saying that is a symbol of the importance of sleep for humanity.

[Ionmars]

If Starship were to be employed only in vertical position, could an inter-ship hallway system still be employed?

I think yes. Crew Starships to be reused as habitats could be placed next to each other so that their doors face each other. An inter-ship connector ring would be placed over and around each door and welded to each ship, airtight. The outer edges of the ring would be curved to match the exterior of each ship (a chord of a circle with 4-1/2 m radius). A person would exit through the door of one ship, pass through the ring and enter through the door of the second SS. This would serve as a very short inter-ship hallway.

To connect multiple ships into a base-wide hallway system, a special variant  of cargo SS would sport four doors facing four directions, as suggested by the sketch below. There could be a series of 4-door units connected together in a line. The side doors would connect to habitat SS's or pressurized cargo units reused as greenhouses, laboratories, and repair shops.

In this particular example the habs and cargo sections of SS were not separated from their respective propellant tanks and propulsion units. So the hallway system and living quarters are elevated 20+ m above ground. In effect, Each SS hab would have its own basement consisting of empty  CH4 and O2 tanks, which could also be converted into living and working space over time.

The sketch shows the initial base cluster of SS's surrounded by a berm or wall built of regolith. This would have to be built up over time to eventually cover the base.

Like other alternatives this approach would have its advantages and disadvantages. A detailed analysis of alternatives will be needed to determine which could be constructed faster and at less expense.

More discussion of this type of approach may be found in the thread "Amazing Mars Habitats." See entries by TheRadicalModerate and others.

[Yggdrasill]

Having considered the different options, I think I would prefer constructing a fully functional lunar base on earth and simply landing it. With sufficient orbital refilling, in stages between LEO and LLO, a Starship could land several hundred tons of payload on the moon. That's enough to include sufficient radiation shielding internally in the fairing, and all the internal hardware of the base.

You would have to transfer some payload in space for this to work. A Starship lunar base could reach LEO with a maximum of around 200 tons of payload, and if you need 200 tons of water for the radiation shield, two reusable Starship launches would be required to launch the water into LEO, and then you would dock and pump the water over into the base.

There might be some added complication in trying to land a ~600 ton Starship lunar base on the moon, rather than the 300 (?) tons of an HLS landing, but this should be solvable with added thrusters. I'm guessing you would land it on a pre-scouted position that's almost perfectly flat, and maybe have radio-beacons to guide it in, which would reduce the complexity of the landing.

Edit: This also works quite well with @lonmars suggested construction method. With the four-port version, you could reduce the radiation shielding on the sides, while keeping the shielding on the top, and maybe shrink the propellant tanks for added habitation volume. With two variants of Starship you could construct a pretty massive and well-shielded base, if desired.

[Pitpen]

My 2 cents on the topic:

1) A lunar habitat module is not being built at the moment and using Artemis and Gateway as a measuring stick it translates into at least 5 years of lead time at best;

2) Starship should be already suitable for long term (months) space environment due to its intended purpose of sending people to Mars, so I think that 6 months lunar shifts would do the trick until a permanent solution will be developed and installed;

3) No need to put it horizontally thus removing the ability to escape Moon in case of emergency, but just use it as it is. NASA has already trusted its high habitat concept and deemed it safe enough to assign 3B$ to transport humans onto it;

   

[Yggdrasill]

The sketch shows the initial base cluster of SS's surrounded by a berm or wall built of regolith. This would have to be built up over time to eventually cover the base.

Just thought of a method for adding regolith between the vertical Starships, or covering any lunar base design really, without needing the regolith to be compacted to allow a bulldozer to drive on top of it. It also allows for steeper slopes than a bulldozer-based solution.

You could actually use something similar to a snow cannon to eject regolith skyward and raining it down on the structure. The relatively low density of regolith, and the low gravity on the moon means it shouldn't rain down with too much force, while also allowing for good throwing distances and height. It's also aided by the lack of an atmosphere. The actual device might be nothing more than a controllable high speed conveyor belt, with probably also some mechanical separators on the input-side, to filter out rocks that are too big/heavy and might damage the structure.

Using such a mechanism for regolith deposition makes it very easy to gather the regolith. You would just need to push regolith into the rotating blades of the input. Or you could have an input suitable for a dumptruck.

[edzieba]

In this concept, the Starship is being used as little more than a cylindrical hollow within a regolith berm. All other work of burying and fitout is the same as if you'd created that hollow in any other manner. If you have an alternate method to create that hollow that can be carried within a Starship, you obviate the need to expend one in the first place.
Barring ISRU methods (not impossible, but simply not demonstrated so low TRL), the two most obvious alternatives are an pressure-supported inflatable bladder (pros: light, compact, you need to pressurise the structure anyway. cons: fail-unsafe in event of pressure loss) or a deployable structure e.g. concrete canvas (pros: fail-safe in event of pressure loss so can be used for airlocks and vehicle garages, durable, a viable structure for operational use even before burying. Cons: greater upmass than pure inflatable membrane, requires some quantity of water to be carried if ISRU not an option).

[Alberto-Girardi]

The sketch shows the initial base cluster of SS's surrounded by a berm or wall built of regolith. This would have to be built up over time to eventually cover the base.

Just thought of a method for adding regolith between the vertical Starships, or covering any lunar base design really, without needing the regolith to be compacted to allow a bulldozer to drive on top of it. It also allows for steeper slopes than a bulldozer-based solution.

You could actually use something similar to a snow cannon to eject regolith skyward and raining it down on the structure. The relatively low density of regolith, and the low gravity on the moon means it shouldn't rain down with too much force, while also allowing for good throwing distances and height. It's also aided by the lack of an atmosphere. The actual device might be nothing more than a controllable high speed conveyor belt, with probably also some mechanical separators on the input-side, to filter out rocks that are too big/heavy and might damage the structure.

Using such a mechanism for regolith deposition makes it very easy to gather the regolith. You would just need to push regolith into the rotating blades of the input. Or you could have an input suitable for a dumptruck.

The idea is interesting, but I think that separating large rocks to a perfect accuracy and mantaining a simple system might be difficult, expecially because only one too large rock thrown could yeld a lot of damage.

[Yggdrasill]

The idea is interesting, but I think that separating large rocks to a perfect accuracy and mantaining a simple system might be difficult, expecially because only one too large rock thrown could yeld a lot of damage.

I'm pretty sure that's a solved challenge in various industrial plants making gravel, concrete, etc. I believe they use things like grates with different hole-sizes where finer material drops through the grate and coarser material bounces off to the side.

But alternatively you could crush the regolith into the required fineness. That way you also don't need to discard any of the collected regolith. The crushing can for instance be done with a set of rollers, where the opening between the rollers is 1 cm. That way no material higher than 1 cm can pass through without getting crushed.

[Slarty1080]

If Starship were to be employed only in vertical position, could an inter-ship hallway system still be employed?

I think yes. Crew Starships to be reused as habitats could be placed next to each other so that their doors face each other. An inter-ship connector ring would be placed over and around each door and welded to each ship, airtight. The outer edges of the ring would be curved to match the exterior of each ship (a chord of a circle with 4-1/2 m radius). A person would exit through the door of one ship, pass through the ring and enter through the door of the second SS. This would serve as a very short inter-ship hallway.

To connect multiple ships into a base-wide hallway system, a special variant  of cargo SS would sport four doors facing four directions, as suggested by the sketch below. There could be a series of 4-door units connected together in a line. The side doors would connect to habitat SS's or pressurized cargo units reused as greenhouses, laboratories, and repair shops.

In this particular example the habs and cargo sections of SS were not separated from their respective propellant tanks and propulsion units. So the hallway system and living quarters are elevated 20+ m above ground. In effect, Each SS hab would have its own basement consisting of empty  CH4 and O2 tanks, which could also be converted into living and working space over time.

The sketch shows the initial base cluster of SS's surrounded by a berm or wall built of regolith. This would have to be built up over time to eventually cover the base.

Like other alternatives this approach would have its advantages and disadvantages. A detailed analysis of alternatives will be needed to determine which could be constructed faster and at less expense.

More discussion of this type of approach may be found in the thread "Amazing Mars Habitats." See entries by TheRadicalModerate and others.

An interesting idea but Starship is 50m high so the amount of regolith required would be huge. Another problem would be how are the Starships going to be neatly arranged like that? I would have thought that they would need to land some distance away from each other to avoid blast damage and transporting a 50m Starship across the Moon would not be an easy task.

[Vultur]

My 2 cents on the topic:

1) A lunar habitat module is not being built at the moment and using Artemis and Gateway as a measuring stick it translates into at least 5 years of lead time at best;

2) Starship should be already suitable for long term (months) space environment due to its intended purpose of sending people to Mars, so I think that 6 months lunar shifts would do the trick until a permanent solution will be developed and installed;

3) No need to put it horizontally thus removing the ability to escape Moon in case of emergency, but just use it as it is. NASA has already trusted its high habitat concept and deemed it safe enough to assign 3B$ to transport humans onto it;

 

Yes.

Also, what's the goal/purpose?

If medium term missions are desired (say several months to a year, similar to stay times on ISS) with a small number of crew, the Lunar Starship can presumably be a sufficient habitat without being tipped over, and with no special modifications (maybe carrying more life support consumables than a regular Artemis mission, but nowhere near what you'd need for 100 people on a Mars Starship).

For really permanent settlement (same people staying for a lifetime) you might need more shielding, and for a larger scale base or settlement Starships might be inefficient - but are there any current plans/stated goals for anything on that scale for the Moon, comparable to Elon Musk/SpaceX's Mars plans?

[Oersted]

I wonder why old supertankers on Earth aren't repurposed as skyscrapers? Just stand them up on one end. I mean, it would be ten times easier than laying a spaceship on its side on another planet...

I know you are being faceteous, but there is a big difference. A Supertanker is not designed to support itself on its stern. A However, a Starship is designed to support itself against a lateral load of > 1 g, which it does during re-entry as it flies with the windward side facing the direction of motion.

Yes, it can deal with an even lateral load, but how are you going to achieve that on a rocky lunar surface, and
just as important, while placing it horizontally?

[DanClemmensen]

I wonder why old supertankers on Earth aren't repurposed as skyscrapers? Just stand them up on one end. I mean, it would be ten times easier than laying a spaceship on its side on another planet...

I know you are being faceteous, but there is a big difference. A Supertanker is not designed to support itself on its stern. A However, a Starship is designed to support itself against a lateral load of > 1 g, which it does during re-entry as it flies with the windward side facing the direction of motion.

Yes, it can deal with an even lateral load, but how are you going to achieve that on a rocky lunar surface, and
just as important, while placing it horizontally?

First, the lunar gravity imposes only a .16 G load,  which is  lot less than the load during re-entry, and I'm not sure how "even" the forces are during re-entry: I understand it's a bit of a rough ride. Next, I would use a rake to clear the rocks, just as you would when laying a patio on sand. I might even add a conformal squishy layer to the outside of the HLS. The existing TPS would probably work just fine, but a specifically designed layer would work better.  There may be very good reasons to not tilt the ship, but protection from the surface is not one of them.

[Lampyridae]

Land in a 50m+ deep crater. Fill the unused space in the cone with regolith and use the area immediately beneath for sleeping. That deck is basically completely shielded save for albedo neutrons.

[sanman]

I wonder why old supertankers on Earth aren't repurposed as skyscrapers? Just stand them up on one end. I mean, it would be ten times easier than laying a spaceship on its side on another planet...

I know you are being faceteous, but there is a big difference. A Supertanker is not designed to support itself on its stern. A However, a Starship is designed to support itself against a lateral load of > 1 g, which it does during re-entry as it flies with the windward side facing the direction of motion.

Yes, it can deal with an even lateral load, but how are you going to achieve that on a rocky lunar surface, and
just as important, while placing it horizontally?

First, the lunar gravity imposes only a .16 G load,  which is  lot less than the load during re-entry, and I'm not sure how "even" the forces are during re-entry: I understand it's a bit of a rough ride. Next, I would use a rake to clear the rocks, just as you would when laying a patio on sand. I might even add a conformal squishy layer to the outside of the HLS. The existing TPS would probably work just fine, but a specifically designed layer would work better.  There may be very good reasons to not tilt the ship, but protection from the surface is not one of them.

Furthermore, you could pile regolith/dust/sand underneath the sides of an horizontally lying Starship, in order to provide support and stability. That could be done as part of covering it with regolith for protection against micrometeorites & radiation.

Since Lunar Starship HLS would already have signifcant habitable volume, this could be used as a shirtsleeve environment to then convert the tank volume into considerably greater living space. With relatively non-toxic volatiles like LOX & CH4, there shouldn't be any major toxic residues that couldn't be purged to space.

With Lunar Starship HLS being overkill for its role as a lander, this could give it extra margins for structural reinforcement modifications to make it a more durable base on the ground.
Just as vertical Starships could be stacked close to one another, horizontal Starships could similarly be linked to create a larger contiguous volume.

[daveklingler]

While lots of studies have been done in this vein over the past 60-or-so years (the ASCE Aerospace Division's body of work is gigantic by itself), we need to remember that the reason for this particular study is that there is only one pressure vessel designed for use in space in mass production.

The point of this student exercise is that anyone who wants to build a huge lunar base could probably buy ten Starships for an order of magnitude less than just the cost overruns on a bespoke hab from any other company. Ten Starships, ten months.  For anyone else, working 40-hour work weeks, certainly five years, and likely ten, for something that isn't self-launching.

So while most of the civil engineering work has been studied to death, Starship will soon become the $1 hammer in a toolbox containing almost nothing else.  Complain all you want that a beautiful spacecraft is going to waste, or that it's not optimal, but at the end of the day there are no other comparable choices.  "When all you have is a hammer..."

[daveklingler]

In this concept, the Starship is being used as little more than a cylindrical hollow within a regolith berm. All other work of burying and fitout is the same as if you'd created that hollow in any other manner. If you have an alternate method to create that hollow that can be carried within a Starship, you obviate the need to expend one in the first place.
Barring ISRU methods (not impossible, but simply not demonstrated so low TRL), the two most obvious alternatives are an pressure-supported inflatable bladder (pros: light, compact, you need to pressurise the structure anyway. cons: fail-unsafe in event of pressure loss) or a deployable structure e.g. concrete canvas (pros: fail-safe in event of pressure loss so can be used for airlocks and vehicle garages, durable, a viable structure for operational use even before burying. Cons: greater upmass than pure inflatable membrane, requires some quantity of water to be carried if ISRU not an option).

Don't forget that there is no location on the Moon that's not fairly close to a smorgasbord of lava tubes in a variety of sizes up to several hundred meters in diameter.  Once you have an established hab, you go shopping for a lava tube, because it's already up there.  There's an ASCE paper from about 30 years back by Cassandra Coombs mapping all of the most desirable candidates.

Lessee here...whups, looks like she wrote several.

https://ui.adsabs.harvard.edu/abs/1992lbsa.conf..219C/abstract