Space Station V

GW Johnson · 2015-08-31 08:40:33

Well, it has to be done in stages. When you first land, you'll be living inside the vehicles that brought you, sitting on the surface. To dig, you'll need heavy equipment, unlikely to be in that first trip's group of vehicles.

So, those vehicles will need some shielding built in, which can be augmented with hand-filled sand bags laid on top, provided the shapes are OK for this, and there is access for an astronaut in a clumsy suit.

Later, with heavy equipment, underground pressurized structures can be built. I know that air pressure inside can hold up lots of regolith mass in low gravity, but the structure must also hold itself up BEFORE you put air inside it. So don't get too excited about how wide-open a space might be possible.

So, all in all, there is still a requirement for those first vehicles to have solar flare radiation shielding. If you have life support at all, you have water and wastewater. They make a fine shield. 15-20 cm of water is all you need. Hide behind it. Flare storms are only hours long.

It's not such a problem on Mars. The atmosphere, thin as it is, provides a lot of shielding against solar flare radiation. Any sort of radiation protection that works on the moon is more than sufficient for Mars.

GW

Last edited by GW Johnson (2015-08-31 08:44:39)

Tom Kalbfus · 2015-08-31 10:57:08

GW Johnson wrote:

Well, it has to be done in stages. When you first land, you'll be living inside the vehicles that brought you, sitting on the surface. To dig, you'll need heavy equipment, unlikely to be in that first trip's group of vehicles.
So, those vehicles will need some shielding built in, which can be augmented with hand-filled sand bags laid on top, provided the shapes are OK for this, and there is access for an astronaut in a clumsy suit.
Later, with heavy equipment, underground pressurized structures can be built. I know that air pressure inside can hold up lots of regolith mass in low gravity, but the structure must also hold itself up BEFORE you put air inside it. So don't get too excited about how wide-open a space might be possible.
So, all in all, there is still a requirement for those first vehicles to have solar flare radiation shielding. If you have life support at all, you have water and wastewater. They make a fine shield. 15-20 cm of water is all you need. Hide behind it. Flare storms are only hours long.
It's not such a problem on Mars. The atmosphere, thin as it is, provides a lot of shielding against solar flare radiation. Any sort of radiation protection that works on the moon is more than sufficient for Mars.
GW

Mars has native water, which can be used as radiation shielding and as water, Since Mars has higher gravity, we can bury the habs underwater in places where there is sufficient native water, as near the poles for instance. We can land in an arctic region and make use of the abundant sunlight and long days during the Martian summer. A cubic meter of water on Mars weighs 0.38 of a ton under Martian gravity, so in order to get ten tons of water pressure squeezing on the habs per meter in all directions, the hab could be submerged under 26.31 meters of water under a crust of ice, which can easily stay frozen in these polar regions. I suppose we could blanket the region surrounding the pond with solar panels and use heaters to heat the water underneath the icy crust of the pond we create, and maybe stock it with fish. We can have something called a "Moon pool" into which one can dive in while wearing an insulated wet suit. The water near the bottom would be around 3 degrees above freezing on the Celsius scale if fresh. Perhaps some mechanism will be needed to oxygenate the water so the fish can live. I think the ice crust on top can be kept clear, as it doesn't snow a lot on Mars I believe certain kinds of plants can grow at the bottom of this pond, and might even regenerate the oxygen within the hab itself. The icy crust will trap in the water and oxygen dissolved within, during the Martian winter, when there is less Sun, perhaps a nuclear reactor can supplement the heaters and provide artificial light under the ice so the plants can continue to grow. What do you think of this idea? Could we construct an artificial pond in a crater from native water near the Martian North Pole?

GW Johnson · 2015-08-31 16:18:54

The ice-covered pond is a construct for Mars that I proposed a few years ago on my blogsite (exrocketman.blogspot.com). Of all the construction items we could build, this is the only one not limited by the square-cube scaling law. You can build these as big as you want, limited only by the available water supply.

I do not think you can leave clear ice exposed at the surface, because it will sublimate away. We've already seen this with the small ice lenses uncovered by the polar lander: they disappeared in 3 days. It is water vapor pressure, not total atmospheric pressure, that you must compare to the equilibrium vapor pressure at the solid ice temperature. At 0 C that is 6 mbar. I know Mar's has a nominal lowland 6 mb atm pressure, but that atmosphere is almost totally dry: the vapor pressure of water in it is essentially zero, no different from space.

That being said, you pile regolith on the ice, and that will stop the sublimation for all practical purposes, as vapor pressure builds up in the porosity adjacent to the ice, displacing the local "air". Between the ice weight and the regolith weight, the pressure in the water can be high enough to allow humans to swim without a pressure suit, only thermal protection and oxygen.

To use such a pond to grow food, you must supply sunlight artificially. Waterproof lamps with some UV content should work nicely. These can be powered by solar PV panels located on top of the ice. I suppose you could freeze some windows into the ice cover that would pass sunlight through, but that presumes availability of glass, which might not be true during the first several decades, except as an import from Earth.

The problem with building such ponds is really industrial-scale excavation and earth-moving. This requires heavy equipment that can be operated robotically or by astronauts in very clumsy space suits. Such equipment is extremely unlikely to be included in the first landing mission.

As for the water supply, you want massive buried glaciers, so that you can merely drill a well and extract liquid water using steam heat. Conventional mining requires much more in the way of heavy excavation and processing equipment, again extremely unlikely to be available in most mission plans.

Such ponds could be fresh or salt water. If salt, it needs to be sodium chloride, and no more saline than Earthly ocean water.
Otherwise, you'd poison the ecology your are trying to set up.

GW

Tom Kalbfus · 2015-08-31 16:40:52

I think if you build the pond in the Polar regions, there would be plenty of water to replace that which sublimates away, after all there is permanent ice in the Martian polar caps. The sublimated ice will redeposit on the caps and you can get some more.

“A crater near the Martian North Pole with a large lake of water ice. The lake is about 10 km across.” – Robert O’Connell, University of Virginia. NASA photo.

Here is some water ice that is already there what if we used a nuclear reactor to liquefy what's underneath? This is a natural radiation shield. Sometimes Mars simply does some stuff for you. We don't need to make an artificial lake of we use this one. How salty it is, I don't know, perhaps we should go there and find out. There is a lot of water here, compared to the needs of say 4 astronauts for instance! A 10 km wide lake is a lot of water, more than you could drink most likely, as for salt, distilling water is easy on Mars, you simply allow it to sublimate and then your re-condense it, just capture that water vapor and re-liquefy it and you have fresh water.

Last edited by Tom Kalbfus (2015-08-31 16:53:04)

GW Johnson · 2015-09-01 12:21:29

The picture looks more like thin snow cover than a frozen lake. The white "cap" has very clear elevation contours (layering) visible. This covering of whiteness may actually be very thin, as evidenced by the gap with the rocks poking out on the upper left, as the photo is oriented. There may not be nearly the "vast" quantity of water there that one might think from similar Earthly pictures.

So, I'd be looking for massive buried glacier deposits to utilize. They seem like the better bet. Some even exist near the equator, from what I read.

"distilling water is easy on Mars, you simply allow it to sublimate and then your re-condense it, just capture that water vapor and re-liquefy it and you have fresh water." Your Earthly perceptions again cloud your thinking. These processes are relatively easy on Earth with atmospheric pressures generally well above 300 mbar, and significant water vapor pressures above 10 mbar.

The essentially-vacuum flash distillation you described is not something you can do outside with minimal equipment, not in a desert-dry near-vacuum 6 mbar very cold atmosphere. Because of compression difficulties in "air" that thin, you will need some significant equipment. At those temperatures, sublimation rates will be slow, although not zero (they cannot be zero, no water vapor partial pressure to equal or exceed the equilibrium vapor pressure), so you will need heating of the ice.

Otherwise, you can vacuum flash liquid water rapidly and easily inside a chamber. You will not easily re-condense until you repressurize, and that gas pressure has to come from somewhere. Air compression is easy here on Earth, because of compressor inlet densities that are significant. There, the same kind of air compression is quite difficult and inefficient, precisely because the inlet densities are so awfully low.

GW

Tom Kalbfus · 2015-09-01 13:35:03

How thin do you think it is? If it were very thin, I would think the ice covering would be more spotty than is shown, it rather seems as a solid oval in this picture. What is that spot on the upper left? Looks to me like an avalanche of rock and dirt on top of that ice, maybe from the crater wall perhaps. Also notice that the upper right portion of the crater wall has a thin layer of frost, I think that might be from the sublimation of water ice from the crater lake surface, as the air currents move up the crater wall, that water vapor condensed on the surface of that crater wall, so it looks whiter than the rest of the terrain. That oval of ice looks pretty solid, I think there is plenty of water there, my guess is that it is ground water that leaked onto the surface from some geologic event having to do with the impact event that created the crater, or maybe some movement of magma beneath the surface heated some ice deposits, this is near the north pole after all, it must get pretty cold there, the sublimation rate might be very slow, that ice might be many thousands of years old!

Void · 2015-09-01 20:36:35

What you would hope for Tom would be something like this:
http://phys.org/news/2015-09-oxygen-oas … earth.html

They occur in Antarctica.

I am not going to say that there are none on Mars, but I don't think they could exist naturally in the present climate. Primarily, because of a lack of melted make up water. You have suggested ground water, but we don't have strong reason to suppose that exists from what we think the conditions are on Mars.

In Antarctica, for a few weeks in the summer, warmer temperatures, and constant sunlight can melt small rivers/streams. This flow ends up on top of existing lake ice (Often), and the weight of the water relative to the ice causes the ice to crack, and the water flows through the cracks into the water reservoir below the ice. This process must add enough water to replace water evaporated from the ice surface around the year.

The other factor that allows these lakes to exist is the solar pond effect. Salt accumulates in these lakes. However, the layer on top is colder, but less salty. This could be in part because fresh water gets added to it each summer, but also could be a factor of the ice thickening over the long winter, and expelling brine (To sink to the bottom of the lake), in the summer, I would presume that solar heat causes the bottom layer of ice to tend to melt, releasing a less salty water.

The upper less salty layer also supports photosynthesis, which produces oxygen.

The lower anoxic layers are saltier, and warmer, and can for instance be around or above room temperature. This is from solar heat.

I think that a Mars like world might just be able to support a similar lake, without the existence of summer running water.

In that method, a glacier would dump ice directly into the lake, to encounter the salty anoxic warm layer, and that method would add water to replace evaporated water. Just possibly this has occurred on Mars at the Equator, if the planets axis were extreme.

Artificial lakes:
If you are going to create a lake of this kind, it presumes that you will cause water to be added to it as needed. This is a problem because the evaporation rate would be very high.

A mechanical method is needed to protect the otherwise exposed ice surface. Several options are possible.

However I am going to suggest that in the end the lake be covered with "Blocks" of encapsulated ice, over the normal ice layer.

So, however you might start to have a lake, if you wanted to expand it, you would add water to its body, and the water would cause the ice to lift up. Then the edges of the lake would have exposed ice. You would bring a transparent plastic bag out to a bare patch, and place it over the bare patch. Then you would quickly fill it with fresh clear water, through a port. You would wait for the water added to freeze, and then seal the port. A bubble of air would remain in the plastic bag, but the bottom of the bag would be covered on the bottom with a layer of rather transparent ice as thick as desired. You would also put a epidermis layer over this whole assembly. That layer would be to protect from U.V. light, and like your outer skin would be replaced as it deteriorated from "Weathering". This will also tend to shed the heat of the U.V. radiating it away into the atmosphere, keeping the ice blocks below cooler.

The bag(s) would only have to hold a peak pressure of a few mb above local ambient, so during the Martian day, due to that pressure retention, and thermal inertia of the block of ice, I believe that stability would be maintained. In fact, I think that block of ice could be so cold from the nighttime temperatures, that very little pressurization would occur at all in the bag, from vaporization of water.

It would be important to build the encapsulated blocks of ice so that they do not absorb very much light, and so do not heat up from solar energy themselves.

Of course I am talking about a tile surface over the normal surface ice of the lake, a horizontal assembly of multiple blocks. The tiled surface would impose pressure over the lower "Normal" ice layer, and so greatly reduce evaporation from the lake. If necessary, the "Cracks" between the tiles could be caulked with something I suppose, but it may not be necessary. The cold of the ice in the bags would also transfer to the underlayment ice, and so discourage vaporization.

So, if you have this impoundment of water, a reservoir that is exposed to visible light, this might promote the habitation of Mars, even if the only life in the lake were microbes. However, using solar concentrators under the ice, I think it may be possible to grow more advanced plants. Easiest would be fully submerged pond weeds (Domestication will be a problem). By solar concentrators, I indicate that the light getting through the ice may be attenuated more than what is needed for the plants, so you would build a solar concentrator which would be in the water, under the ice, and which would shine concentrated light on your subject plant.

Such devices could be attached to cords, to the warm bottom below. Humans would be in a room temperature environment, and might pull those down temporarily to the bottom to plant and harvest them. Obviously they would want to harness Oxygen in the colder upper layer.

So, then the source of water. Glaciers perhaps, but how about the polar ice caps themselves? In fact it might be reasonable to have very large impoundments from such a large reservoir of water.

Another thing about considering living on the bottom of a lake/sea/ocean on Mars. If your building leaks, it leaks water in, and air bubbles out.

There should often be time to remedy the situation, or evacuate to another building, swimming in warm bottom water with just breathing assistance.

On the surface, at the air pressures currently existing, an equal sized leak would instead quickly lead to death producing conditions, and the chances of remedy or evacuation would be rather small.

Solar energy? Well, some studies indicate that even now there should be significant exposed ice, where sunlight melts small pockets of melt water (Contained by the strength of the surround ice, not a ice/water column). So, it is not that wild an idea.

However, I am going to bet that in about 100 years or less there will be fusion power, and indeed plenty of power to power a Martian colony, and it's waste heat could be dumped into the polar ice caps, to indeed build Lakes, Seas, and perhaps even Oceans, with an Oxygen layer long before the atmosphere will ever have significant Oxygen.

Last edited by Void (2015-09-02 09:04:43)

Void · 2015-09-02 08:11:42

As a supplement to the last post I made, I can point out that any terraforming scheme involving greenhouse gasses would likely first release the CO2 deposits in the polar ice caps. Particularly the one in the South polar cap. According to my reading, that would elevate the average pressure on Mars to 11 mb, and reportedly that would be enough to allow for snowfalls, and melt water, and temporary streams, so it is likely that during any such terraforming scheme, an approximation of Antarctic conditions of the dry valleys would be achieved rather early, and very likely natural forces would begin to build such lakes.

However further human interventions to promote their formation would make a lot of sense at that point I would think. Methods such as ice block coverings, and diversion of temporary streams of melt water into the lakes, before they evaporate.

Last edited by Void (2015-09-02 08:20:06)

GW Johnson · 2015-09-02 16:25:50

Look, this is what you must deal with: terraforming activities WILL NOT happen on the first mission to Mars. On the other hand, there WILL NOT BE MORE THAN ONE government-sponsored mission to Mars. That means NO government-supported bases. Period.

Now, you all decide what might be brought along on that one-and-only government-sponsored mission to Mars. Whatever it is, that sets up any subsequent missions to Mars. Those will necessarily be largely privately-financed. Governments WILL NOT go twice.

They (the commercially-sponsored missions) WILL NOT happen anytime soon, unless some infrastructure is left in place by the one-and-only government-sponsored mission. You all need to face up to that. It's just a fact of life at this time in history.

That's the reality for anything that might happen during the 21st century. So, deal with it. Adjust your Mars mission plans accordingly.

GW

Void · 2015-09-02 17:03:09

When setting a short term objective, I would prefer to look at the long term potentials. In the case of the Norse Greenland colony, strangely, even though that group of Norse, would sail the north sea, they would focus on finding sheltered fjords where they could farm.

https://en.wikipedia.org/wiki/Fjord

They liked it that way, and that is how they may have lived in Norway prior to Iceland.

However, if I have the story right, they did not seem to be interested in fishing, or catching sea mammals.

I would defer to more traditional "Greenhouse" methods for sure, as a start of a settlement, particularly if that is something that can be well rehearsed and simulated prior to a mission.

But I will say that most of the thinking I notice about Mars seems to indicate people have a mind set that it is going to be like the South West of the North American continent. It looks like it to a large degree, but in reality it is much more like the dry valleys of Antarctica.

To also rehearse what methods would be well suited to Mars as it really is, is not wrong.

The reality is that Mars at it's best will likely be a poor relative of our higher latitude areas even after terraforming. That is not to say that humans could not have a prosperous existence there, but the price for that will be mostly technical adaptation and the manipulation of large amounts of liquid water.

The lessons of those lands, especially at the highest latitudes are that life prospers more in bodies of water than on the land at the same temperatures.

So indeed the mission(s) have to be focused on what is possible, but if they do not lead to a solution to harmonize with what Mars actually would be willing to give to the human race, they will be a waste of time, except for scientific discovery, I suppose.

Further, I am more optimistic than is typical here.

I see NASA is focused on asteroids, since the inhibitors forbade them from actually doing anything else.

Private concerns are approaching the ability to launch items such as the Bigelow expandable modules into space.

It looks like there could be new propulsion systems started, and improved in the next 5-10 years. For instance perhaps the Vasimr.

So, as a mission to Mars is likely still fairly far off, I do not feel restricted to the present available hardware, or it's directly similar devices alone.

And honestly I would have preferred that you comment on the posts I made, instead of trying to bypass them.

Last edited by Void (2015-09-02 17:06:10)

SpaceNut · 2015-09-02 18:31:28

Well Tom Kalbfus, we are far off topic again so how do you think the topic compares back to the tv series
and of how we invision living somewhere out there.....

SpaceNut · 2015-09-02 20:02:40

off topic reply...

GW Johnson, The question I would have for government is why are they doing the ISS and if we can get a real answer other than to control the high ground, to do science ect... then we have the answer as to how we must go forth as well as forward into the future in order to make a moon base and to finally to stand on mars for good.....not just a one time visit.

Now does the private sponsored commercial industry really need an infrastructure left behind on the moon or mars before they will get the means to go is one that unless gornment decides to give up its rights to man it then there is no infrastructure left behind for the commercial industry to make use of. But if the commercial industry were to partner in such a mission so as to have partial rights by providing its own way to the moon at the time that a government sponsored mission occurs then there is a chance for them to continue to go even when nasa does not.

They are developing the launch vehicles that are close but they still need some more work to catch up to what would be needed for such an undertaking.

SpaceNut · 2015-09-02 21:00:03

off topic reply...

Void, on the sheltered fjords and greenhouse the way that the shape of the fjords valley to mountains that border it cause an artificial barrier that redirects the winds and cooler temperatures that allow the ocean temperatures to rise just a bit as well in these isolated valleys. This is simular to creating a dome to cover a small crater and turning it into a mars greenhouse as enclosing it would allow for the same effect to happen but to aid it we also need a bit higher internal air pressure as well to help keep water in a liquid form so as to make it so that the plants we grow could remain able to get nutrients to its roots.

Tom Kalbfus · 2015-09-02 22:18:50

Well actually a Moon base is a space station that rests on the ground, it is still in space because on the Moon, space meets the ground. Place the space station on the Moon's North Pole and it will have 24 hour 365 day per year access to sunshine, and there is less space junk on the Moon than orbiting in low Earth orbit.

Belter · 2018-09-13 14:36:57

I've been working on a design for a space station in my head that uses 20m long quasi-octagonal sections that are 6m wide. These would be straight on the outside, but would have a gently curving floor on the inside. The idea is to construct these with industrial 3D printers out of aluminum or mix of metals in a way to maximize strength to weight ratio. The 2 floors would be stressed members, as would be ibnternal braces that distribute the force of the centrifugal effects. The 1G ring would contain 16 of these (work/living), with 16 more acting as spokes (hydroponics). Then a ring at .6G with 8 sections (aquaponics/filtration). Then 8 more spokes connecting to an assembly of 9 units (0G in the center and water storage units) attached like a large axle 18m-20 wide. I have two versions in my mind, one is 100m in diameter, the other is closer to 120m, using 24 modules additional modules spun sideways, acting as joints, which increases the diameter and slows the rotational speed a bit, as well as nearly doubling the size of the work space. At 100m, 1G is about 3.8 turns per minute. The first floor would be a continuous loop, the second floor couldn't be, but would be crews quarters, with each 2nd level holding about 20-30 crew members depending on layout, so around 300-400 crew members possible, with the main limit being sustainability. But the first level would have a large 2m wide and tall airlock between sections so people could walk between sections seamlessly. It would take about 75-80 launches, plus supplies. Sections could be automatically welded together after docking by integrated electron beam welders which only function in a vacuum. Pressure doors could be closed in the event of catastrophic air pressure loss in any given section. These could simply be light weight doors that are held in place by air pressure against rubber seals. All sections would have integrated maneuvering thrusters at each end to get them into place, but would then integrate into the entire section via network control in order to maneuver the entire station and spin it up to 1G. Each section would use a wireless mesh network system to connect it to the command center and each section would be essentially identical and contains the necessary air scrubbers, computer systems, thrusters to operate independently in case of some sort of large scale accident.

By far and away, I think the biggest issue I've seen with space station "designs" is that they all appear to be assembled in space from scratch. Most appear to take absolutely nothing about the logistics of getting the parts and assembling them. Just connecting two sections together in a way that avoids heavy docking apparatus and tiny holes to crawl between sections is hard enough, the ability to hand assemble a space station like building house is just not possible. The only way we can get to that level of construction is with robotics, industrial 3D space printers and near asteroid mining systems. My design is something that could actually be done now. In fact, each section is quite a bit smaller than the BFG which is 9m in diameter. The only thing that needs to be done is keep the weight down to a reasonable level, which I think can be done pretty easily using advanced 3D printing to make the unit from a single piece.

In fact, 3D printing allows the exterior of vertical spokes to contain a corrugated cross section that would allow the creation of high capacity solar stills integrated into the system. Toilet water would first be recycled through the hydroponics section, as would be the fish tanks in the .6G section. Then it would be filtered and used as shower water. Shower and drinking water would be recycled through the solar "skin" of the hydroponics sections, which would evaporate the water on the sun side, and condense it on the dark side, as many times as required to get pure water at the outlet. With the intense solar energy available, thousands of gallons could be recycled per day without any problem. Hydroponics would scrub the air with little to no need for air scrubbers. Water tanks would all hug the zero G section that would hold up to 800,000 gallons of water in very low G. Because the skins have a layer of corrugated skin, then a space for vacuum insulation, then another layer of corrugated skin, about 3-4" thick in total, any meteoroid would have to penetrate at least 6 layers of metal and water before breaching the hull. The corrugated structure is lightweight, but creates high strength and causes meteoroids to shatter and lose energy due to its ablative characteristics. Any puncture that causes water loss would simply have that water channel or channels shut off while repairs are done.

Last edited by Belter (2018-09-13 17:05:02)

spacetechsforum · 2018-09-13 23:50:18

Bleter, You design is interesting but are you sure that there exist right now a 3D printing technology that can do what you require? If i understand correctly you are proposing a 3D printing in space. I mean even best big scale 3D construction done on earth in atmosphere with oxygen (which i quite important when we are talking about some 3D printing materials) are not very precise. There is also this gravity issue and pressure issue. Also you do not cover at all the problems of heat equilibrium and space radiation.

Belter · 2018-09-14 08:27:21

No, the hull would be 3D printed on Earth. And, yes, the technology exists or is in development. There may still be issues with it. I'm trying to find the page, I think the most advanced one is in Finland or another Scandinavian country that can print over a large circumference. Some of it could be done with conventional welding, but the skin is actually designed to be water cooled and to transfer heat around the circumference. Much of the water would be stored in the skins of each subsection. Water is good radiation shielding as well, so with 3D printing, the hull is not just using water cooling and storage, but can help lower the radiation.

Belter · 2018-09-14 09:00:54

You can imagine the hull buy simply taking corrugated cardboard and forming it in an octagon. Then another layer that is set off with a few mm of spacing for a free vacuum between. This prevents too much heat transference from solar energy since space is a near perfect insulator. I think this would be too complicated to build without 3D printing, but it creates a wide array of options for cooling, for water recycling and storage, for radiation shielding etc. Remember that the intense heat on one side would be absorbed by processing water through an integrated solar still arrangement, and the water would condense and transfer heat to the dark side of module. Once the water has been processed in the spokes, it can be transferred via gravity to the outer rim modules which would use the water as a heat and radiation shield before it is used. I guess the only question is if there are some forms of radiation that can actually accumulate in the water that could be dangerous to ingest. I haven't looked into that.

Belter · 2018-09-23 12:23:41

This new 3D manufacturing technique using bulk metallic glass may be a good way to create a corrugated highly insulated, high strength, water cooled and meteoroid-resistant spaceship/space station hull that could be easier and cheaper to produce than an aluminum one.

https://www.elsevier.com/about/press-re … -for-metal

https://www.sciencedirect.com/science/a … 2104001245

SpaceNut · 2018-09-23 17:17:39

Thanks for those links on the 3D materials.

Bulk Metallic Glasses (BMGs) made from zirconium, titanium, copper, nickel and beryllium, with alloy formula: Zr44Ti11Cu10Ni10Be25. feed stock.

The fibers are then extruded into a 400°C stainless steel mesh wherein crystallization does not occur until at least a day has passed, before a robotically controlled extrusion can be carried out to create the desired object.

Several issues come to mind in space, no gravity to make the extrusion fall to the layer that its being applied to, nothing to anchor the printer to as well as the platform to build it on, space temperatures while in orbit would cycle like it does on the iss due to orbital speed from icy cold to scrotching hot...

Belter · 2018-09-23 19:47:24

SpaceNut wrote:

Thanks for those links on the 3D materials.
Bulk Metallic Glasses (BMGs) made from zirconium, titanium, copper, nickel and beryllium, with alloy formula: Zr44Ti11Cu10Ni10Be25. feed stock.
https://www.elsevier.com/__data/assets/ … -metal.jpg
The fibers are then extruded into a 400°C stainless steel mesh wherein crystallization does not occur until at least a day has passed, before a robotically controlled extrusion can be carried out to create the desired object.
Several issues come to mind in space, no gravity to make the extrusion fall to the layer that its being applied to, nothing to anchor the printer to as well as the platform to build it on, space temperatures while in orbit would cycle like it does on the iss due to orbital speed from icy cold to scrotching hot...

You build the hull on the ground. The 3D printing allows you to integrate cooling systems and other design tech that wouldn't be possible with other manufacturing methods. Of course, 0G 3D printing will be possible at some point, it's just a matter of using the right kind of sticky materials that can be melted and cool properly.

Terraformer · 2018-09-24 03:27:41

You might be able to embed systems with 3D printing, but it's not a good idea. Critical systems should be easy to access and repair or replace as needed.

Belter · 2018-09-24 09:57:52

Terraformer wrote:

You might be able to embed systems with 3D printing, but it's not a good idea. Critical systems should be easy to access and repair or replace as needed.

The idea is partially for strength and also redundancy. Mainly tubes, storage, ducts, etc, so they can be part of the entire structure rather than added in. Things that can last the length of the module itself. Not so much electronics. It's possible that a water distillation or water cooling channel could be irreparably damaged by a meteoroid, but there would be so much redundancy that it wouldn't matter, except maybe over hundreds or thousands of year.

Belter · 2018-10-01 13:17:43

Okay, so I've done my mini "SSV" design here. The difference is, SSV was built from scratch in orbit. This can be sent by about 73 Falcon Heavies. It is only about 5000 tons, versus the 140,000 of the SSV, but still could easily fit 200 people, and possibly even fed them all, with 6000+ square meters of hydroponics and 8 aguaponics bays. There are two levels in the 1G ring, 1 level in the .6G ring. ~121m in diameter. Over 6000 square meters of 1G work area. A 20m x 6m 0G lab in the center. Around that are 8 water storage units with a central pass through to the spokes. The spokes appear to have ladders, but there was no open elevator icon. The lower 1G level is continuous. The connecting portals are 2m x 2m and each section uses electron beam vacuum welds to connect, along with external bracing. The octagonals represent sections that are turned sideways, extending about 7m out in each direction. This allows future clones of the station to be brought together in stacks and doubling, tripllng or more, the amount of space. Eventually, the sections between could be enclosed using materials mined in space and robots. The spokes contain all the hydroponics systems, the .6G ring all of the aguaponics systems for raising fish.

Last edited by Belter (2018-10-01 13:18:40)

Belter · 2018-10-02 09:56:24

If you notice above, each face of the perpendicular science labs will have to have the center 6m cut in with an 11.25 degree angle on each side. This to meet up with the individual outer ring modules. The .6G ring will require two 22.5 degree cuts as there will only be 8 inner ring modules. Or, more likely, each inner ring module will *also* have an 11.25" angle on each end to allow the same interconnecting module to me used. All the modules are semi octaganal, with 4 sides being ~3.8m and 4 sides being about 1.55m. The connection points will have to be electron welded, inside and out and would allow for the passage ways to be 2m x 2m, enough to facilitate walking between modules with no ducking, no waiting for others. The floor spaces in the first level would vary a little, between about 5m and 6m. Waste water tanks would be near the ends of each module, underneath the curved floor. This would be pumped into the agriculture spokes where the water would first filtered through hydroponics, along with water from the aguaponics labs. De humidifiers would capture evaporated water, while a solar still integrated into the outer skin of the agriculture spokes would boil and condense water in larger quantities through multiple passes. This would then be used as shower water. Shower water would be recycled directly through different legs of the solar stills directly to drinking water. Any additional temporary storage or processing of water would be done in the connecting labs that connection the agriculture and aguaponics spokes in the .6G ring. Long term storage of fresh water would be in .1G tanks surrounding the 0G lab. Each tank could store approximately 400 cubic meters of water or about 100,000 gallons if needed. A minimum of two storage units would be needed for backup water, so the other 6 could be storage units or micro gravity science labs.

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