Colonizing / terraforming small asteroids

Calliban · 2022-06-06 15:14:15

kbd512 wrote:

Calliban,
How much energy would we have to provide to internally power a 50km diameter artificial moon habitat?

It would take a lot. I think it depends on population. The average human requires about 10MJ of food energy per day. To grow that using artificial light implies a power expenditure of 10kWe per person, 24/7. So a population of 1 million would need a power source of at least 10GWe just cover food energy. If we develop more efficient ways of producing food, maybe it could be less. To power an ecosystem, which involves other plants and animals, it would be somewhat more. Huge energy requirements only become affordable in systems that combine both high power density and economy of scale.

KBOs and outer planet moons are deep cold, on the order of 50K. To heat a single cubic metre of ice from 50K to 300K and melt it, would require about 1GJ of energy. Let us assume that we start with a 1GWe reactor, producing 3GW total heat and all waste heat from the power source goes into the ice. Such a reactor would melt 95 million cubic metres of ice each year. It would take 10.5 years to melt 1km3 of ice. Once melted, the insulation provided by tens of km of overlying ice would effectively trap the heat within the core of the body. To melt out a cavity say 20km in diameter, would take 44,000 years using a 3GWth energy source. Eventually, a steady state will be reached, under which thermal conduction through the ice balances heat addition from the interior energy source.

Such aquatic habitats are in many ways less than ideal for humanity. Any habitat under the ice woukd be in close to zero gravity. But the ice would trap in both heat and dissolved gases. Provided there is an effective way of recycling all nutrients, the ecosystem should last for as long as the energy source remains operational.

Last edited by Calliban (2022-06-06 15:26:44)

Void · 2022-06-06 18:12:14

Of course I will intrude. Right away I have thought about adding metal and ice structure. And I do not rule that out, but for now I am very interested in your presentation here.

This caused me to think of Mercury, and then Io. Both are pretty much considered beyond means, but maybe it is just that we don't have the method yet.

One thing is true, both of these are potentially huge engines of power, therefore for extreme rewards perhaps we might consider new methods.

Query: "utube, colonizing mercury"

Response: https://www.bing.com/search?q=utube%2C+ … 9811af4c3f

It seems that few or none are those who considered colonizing IO. So I get to be a major crazy.

So, for Mercury it is pretty up front. The planet has lots of Carbon it seems, and water ice of significance in it's polar shadows. So to make useful machines that run on solar energy seems obvious. Balloon Shells? Maybe. Venus has Nitrogen to offer.

For IO, radiation is of course a terrible problem. I recall that some people, (A Russian), have considered a machine that might knock particles out of the magnetic field.

Isaac Arthur has suggested the humans may build an augmentation for the Earth's magnetic field.

If we anticipate the chances that the human race may become very powerful and advanced, could they make magnetic bubbles to protect certain locations in the orbits of Jupiter?

Sulfur is supposed to be a good building material resembling metal in a vacuum. IO can offer Sulfur.

Shells, once built can offer some form of radiation protection perhaps, as well.

If I understand it properly the tidal energy of the moons of Jupiter, where it exists, is primarily from the spin of Jupiter. A vast energy source that should take a long time to run down.

It is obvious that IO is hot because of it for most of its body except much of it's surface. This then is energy potential, I am sure.

Then for the moons of Jupiter, I feel that tethers that reach out into space can generate electric power by the passage of the spinning magnetic field of Jupiter past the moons.

Could IO be converted into shells of worlds, and even then harvest energy of the spin of Jupiter?

Well, it is sort of roughed in at this point. Granted, there are huge burdens to get to that point.

But if we are going to have a solar civilization and perhaps eventually even more than that, this one looks like a treasure chest to me.
But it will be very hard to domesticate such a thing.

Done.

Last edited by Void (2022-06-06 18:50:18)

Mars_B4_Moon · 2022-07-27 07:19:16

After analyzing data from the spacecraft’s historic asteroid sample collection, OSIRIS-REx teams have discovered that the surface of Bennu is extremely loose and that the Sun causes asteroids to regenerate their surfaces much faster than Earth
https://twitter.com/haygenwarren/status … 2450459648

There was also a Nuke Bennu thread around here somewhere on newmars

Mars_B4_Moon · 2023-03-06 05:02:20

China plans robotic spacecraft to collect samples from asteroid
https://www.spacedaily.com/reports/Chin … d_999.html

he Chinese government has approved a plan to send a robotic spacecraft to collect samples from an asteroid, according to the China National Space Administration's Lunar Exploration and Space Program Center.

The mission, called Tianwen 2, is designed to launch a probe to obtain samples from the 2016 HO3, the smallest and closest "quasi-satellite" to Earth, and bring them back. After accomplishing this goal, the main part of the craft will continue to fly toward a main-belt comet to explore it, the center said on Thursday in a notice inviting scientists to a workshop on this mission.

The workshop is scheduled to take place in Hefei, Anhui province, on April 27 and 28 and will be open to researchers from the Chinese mainland, Hong Kong and Macao special administrative regions, and Taiwan.

Main topics will include the Tianwen 2's basic plan, scientific goals, mission payloads, operational patterns as well as updates on asteroid studies, the center noted.

According to Ye Peijian, a leading spacecraft researcher at the China Academy of Space Technology, the asteroid mission's basic idea is to use a large carrier rocket to send a probe consisting of two parts - an orbiter and a reentry module - toward the 2016 HO3. After approaching the asteroid, the spacecraft will first orbit around the small body and then fly very close to it to use a mechanical arm to scoop dusts from its surface. Carrying the samples, the probe will fly back to Earth orbit and release its reentry module, allowing it to fall back to the ground with the samples.

The orbiter will then travel toward a main-belt comet named 311P to continue its scientific exploration tasks, he said.

Scientists have identified about 1 million asteroids in our solar system, with more than 20,000 of them traveling near Earth.

2016 HO3, also known as 469219 Kamo'oalewa, was first spotted in April 2016 by an asteroid survey telescope at the Haleakala Observatory in Hawaii.

Calliban · 2023-03-09 11:51:54

Isaac Arthur discusses terraforming.
https://m.youtube.com/watch?v=HV4IfsJ7vHU

I think his conclusions are similar to mine. By the time humans develop the capability to do these things, we will be building space habitats at a rate that makes the land value of a planet a poor return for the invested resources. However, we will still be mining materials to build those habitats. If large asteroids and dwarf planets end up riddled with caves as we mine out materials, perhaps those caves will be pressurised and made habitable? This is how shell worlds could end up being created. Pillar and room mining on a massive scale. But by the time they are, they will be a side show, as trillions of people will be living in rotating habitats where they can design any environment they want. A billion people living in a shell world will be the solar system equivelent of Albania. Everyone knows its there, no one wants to go there.

Void · 2023-03-09 21:40:39

Your thinking seems reasonable to me.

I have a hard time thinking that we should have such a big apatite as Isaac Arthur implies, but who am I to limit the people of the future, if any do exist then.

Big Appetite: https://www.bing.com/videos/search?q=Is … ORM=VRDGAR

But Isaac Arthur is a good entertainer and also a teacher.

It is just fine

Done.

Last edited by Void (2023-03-09 21:41:11)

Void · 2023-03-10 09:47:40

I have been interested in Extraterrestrial "Cold Terrestrials" for some time. Mars could be considered one. Technically, i the early history of the solar system Earth could have been considered one at times, the sun was only 70% as bright as now. It may have had snowball episodes we don't know about.

In this article, they say that the "Snow Line", I presume for water ice, was about 2.7 AU during planet formation and is about 5 AU now.

At the time of the 2.7 AU, the suns brightness would have be ~70% of what it is now, I believe. We say that Mars is 1.5 AU from the sun.

If Jupiter had been different, it might have been possible for significant terrestrials to have formed in the zone 1-2.7 AU, and they would tend to be colder than Earth and could possibly lock into a snowball Earth type situation, and not be able to emerge from it.

A terrestrial between the size of Earth and Mars, could hold a Nitrogen/Argon atmosphere, but I believe it would have .25% as much light as Earth, presuming an identical star as it's sun. It would be colder than Earth, by far, presuming a 1 bar atmosphere. CO2 could likely accumulate at the poles as ice, so not much hope of it doing a significant greenhouse effect.

So, it would be a "Cold Terrestrial" It could have under ice seas, and likely would have volcanism.

So, there would be a band of "Cold Terrestrials" outside the habitable zone, possible. And those would be of some interest to interstellar travelers, as they would be more likely to be sterile, and so that issue as a problem is reduced. They would be good radiators, so actually you could move a lot of energy to them, much more than the Earth can handle.

Done.

Last edited by Void (2023-03-10 10:06:47)

Mars_B4_Moon · 2023-03-20 11:04:22

Asteroid feared to hit Earth in 2046 will almost certainly miss, NASA says
https://www.space.com/asteroid-2046-wil … miss-earth

Microbes to Demonstrate Biomining of Asteroid Material Aboard Space Station
https://www.nasa.gov/mission_pages/stat … -spacex-21

Space Habitats
https://www.youtube.com/watch?v=0EkX9vARGww
another vid from Isaac Arthur

and just in case u tube tries to copyright strike or ban him for using a sound clip or video clip for some video game he has many other channels across social media and people who mirror his vids

https://www.bitchute.com/channel/Qa7hqB57hZTw/

https://rumble.com/IsaacArthur

https://odysee.com/$/search?q=IsaacArthur

https://gettr.com/post/p2a91dh7662

https://twitter.com/Isaac_A_Arthur

Void · 2023-03-20 19:38:43

I currently have an interest in a family of outer belt asteroids.
Here is one member: https://en.wikipedia.org/wiki/222_Lucia … 20material.

Belonging to the "Themis" family: https://en.wikipedia.org/wiki/Themis_family
Quote:

The Themis family (adj. Themistian; FIN: 602) is a family of carbonaceous asteroids located in the outer portion of the asteroid belt, at a mean distance of 3.13 AU from the Sun. It is one of the largest families with over 4700 known members,[1] and consists of a well-defined core of larger bodies surrounded by a region of smaller ones. The collisional Themis family is named after its parent body, the asteroid 24 Themis, discovered on 5 April 1853 by Italian astronomer Annibale de Gasparis.[2]

Quote:

List
See also: Category: Themis asteroids
Some of the largest members of this family include:[4][5]
24 Themis
62 Erato
90 Antiope
104 Klymene
171 Ophelia
222 Lucia
223 Rosa
316 Goberta
379 Huenna
383 Janina
468 Lina
492 Gismonda
515 Athalia
526 Jena
767 Bondia
846 Lipperta

There are links to each, in the main article:
https://en.wikipedia.org/wiki/24_Themis

Quote:

Surface materials
Ice
On 7 October 2009, the presence of water ice was confirmed on the surface of this asteroid using NASA’s Infrared Telescope Facility.[14][15] The surface of the asteroid appears completely covered in ice. As this ice layer is sublimated, it may be getting replenished by a reservoir of ice under the surface.[16][17]

So, some of these are from 26 to 200 km in size and sort of like Ceres in composition, so these may be of some interest. I guess if it turns out that the gravitation of Ceres is not useful, then I would be looking at asteroids like these.

So, yes we are going to want to know about low gravity situations and their uses.

Done.

Last edited by Void (2023-03-20 19:50:04)

Calliban · 2023-03-21 07:48:44

Void, that is interesting. The outer belt appears to represent the snow line of the solar system. It is an interesting place, because the asteroids there are volatile rich but still close enough to the sun for solar power to be useful as source of energy. Ultimately, these bodies could be a future home for humanity and whatever lifeforms we choose to bring with us.

Void · 2023-03-21 08:58:11

What I am reading lately is that these types, perhaps including Ceres are thought to have formed near Uranus or Neptune. Planetary migration bumped them to where they are now.

https://mashable.com/article/asteroid-w … 20of%20H2O.
Quote:

NASA just found a new type of ancient asteroid loaded with water
Could these space rocks help explain how water got to Earth?

The Finns already think that Ceres is a good candidate as it should have accessible Nitrogen.

The Themis group may be similar, but is shattered, and so it may be that layers which are deep down on Ceres would be exposed on the objects of the Themis group.

Something like the difference between a whole agate and a broken or cut agate.

To me that indicates a possibility of a broad spectrum of materials. Also some near by asteroids may prove to be metallic, and that could complete the spectrum.

https://skyandtelescope.org/astronomy-n … ar-system/
Quote:

Analyses of just 5.4 grams scooped from the asteroid Ryugu are delivering rich new insights into the history of the solar system.

https://scitechdaily.com/asteroid-belt- … -realized/
Quote:

In this artist’s conception, Jupiter’s migration through the solar system has swept asteroids out of stable orbits, sending them careening into one another. As the gas giant planets migrated, they stirred the contents of the solar system. Objects from as close to the Sun as Mercury, and as far out as Neptune, all collected in the main asteroid belt, leading to the diverse composition we see today. Credit: David A. Aguilar (CfA)

So, if we go out there we may have parts from everywhere in the solar system proper.

It also suggests that trojans of Neptune and the Kuiper Belt may have a variety of objects as well, which I consider to be good.

So, the Dwarf Planet Ceres was formed way out there, it is thought and then migrated inwards. The Themis group however gives us a multitude of various sized objects, and possible access to deeper layers uncovered.

Ceres seems a good thing, but these may be even more suitable.

Done.

The Finns have a concept of a mega satellite for Ceres: https://www.sciencealert.com/could-huma … anet-ceres
Quote:

That is a "Clam-Shell" set of mirrors, which also may block impactors and the plate between them has dots which each represent a O'Neil Cylinder.

I am considering a shell as well, but not as normally considered. For a relatively small asteroid, we might consider enveloping it in an unpressurized shell also, I am considering.

This is a raw notion and I want it to be raw, as I want to stimulate the production of many variants.

If you have two or more shells, you do not have to pressurize the interior, just the space between shells. And you may also partition that into cells like a honeycomb. You may have leaders??? which connect the two shells, so that the pressure pushing the outer shell outward can be counterbalances with the inner shell being pushed inward.

The shell can be sun-locked, or perhaps a tidal lock simulation if that helps.

The asteroid is free to spin.

Or you can spin the shell with the asteroid. In that case you may even harvest the spin of the asteroid to fling stuff perhaps, with mass drivers and/or tethers.

Various solar power schemes are possible.

For smaller objects with small gravity this may be possible, where I do not think it likely for Ceres. For Ceres, you might make the Double Shell orbit the asteroid. Obviously, this does not preclude the concept the Finns have offered. Or O'Neil.

The inside of the inside shell, would be largely unpressurized???, but maybe low pressure O2, so that compressors would feed a ship or spacesuit.

But the interior could be lighted, and of a proper temperature and relatively safe from impactors, and with power supplies and other needs filled. If low pressure then spaceships could be conducted into the interior for service. Of course you would have to protect from explosive incidents by purging them of problem substances first.

Just some silly putty for the mind.

Done.

Last edited by Void (2023-03-21 19:29:40)

Void · 2023-03-21 13:19:34

OK more thoughts about the circular depiction.

Most animals have vacuoles inside of them. But what is in them is not a part of their body. So, the double shell is a body, and what is in it is in its digestive system, I guess. So what is in the double shell is in one envelope, and what is in the stomach, is in another envelope.

The body envelope tends to have a more consistent content over time spans, but the stomach vacuole can be changeable.

So we would have things like robots inside this double envelopes stomach, and portals that can open and close to isolate or merge in a close or open manner the communication between the stomach and the vaster space environment.

So, that emerged in my mind over lunch, for what it is worth.

We can often look to nature to figure things out.

Done

Last edited by Void (2023-03-21 13:25:34)

Calliban · 2023-03-21 18:52:36

Void, the Finnish design is fascinating. I think the first place this will be built is High Earth Orbit, probably L5. The interesting thing about it is that the plate upon which the habitats are mounted could have zero-gee structures as well. Large, shielded, non-rotating sheds could provide a safe, low-g environment for construction of new habitats, solar power satellites and interplanetary spacecraft. The really neat thing about mounting many habitats and structures to a plate is that no propellant is then required for transportation between habitats and other structures. Trains can run along the plate and all impulses can be balaced to achieve zero net force on the plate. So humans can travel about freely using solar electricity and needing no reaction mass.

Far from the sun, in the Oort cloud, sunlight is no longer an effective source of power. In that environment, a more suitable arrangement would be a metal sphere or ring, perhaps 1000km in diameter. Habitats would be attached to the outer surface of the sphere or ring, with the densest concentration of them around the equator of the sphere or distributed evenly on the outer surface of the ring. As the conglomeration grows in size, the gravitation of the collective structure will become a nuisance, requiring thrust brearings on rotating habitats. By rotating the sphere or ring at just the correct rate, centrifugal force can be made to cancel out gravitation. Our O'Neill habitats will not need bearings.

The number of inhabitants living on such a world could be huge. As always, the thing that end up limiting the human habitation density is the need to radiate waste heat. Having habitats mounted on a sphere does help somewhat, as heat can be radiated in all directions from an emitter mounted on the surface. We can also have radiator panels extending a long way into space from the poles of the sphere. In this way, individual habs and structures can use the sphere as a heat sink.

A vast ring world could be built to almost arbitratry sizes. So long as the ring rotates at a speed that allows centrifugal force to counteract gravity, we could build rings of any size we want, with potentially millions of Island 3 habitats mounted on its outer surface.

Last edited by Calliban (2023-03-21 19:06:55)

Void · 2023-03-21 19:14:53

A very good expansion of the concept Calliban. I agree with your thinking. As it happens though the Finns do intend to use magnetic bearings to keep the rotating habs associated with the "Plate".

I have moved a bit further with the concept of a collection of mechanical organs.

I moved to Packman.

The sphere would be chopped in half and be hinged. So then it could envelop orbital materials. In the open mouth mode, it then is maneuvered to envelop the mass to work with, such as a NEO. Or there may be many small objects to consume in the asteroid belt.

When closed, then it can be buckled together at the edges and airlocks could join the pressurized areas of the two shell half's.

So, now the "VOID" inside the two joined half shells is mouth, stomach, and other things. For instance since it is likely that the materials to process will be built into structure then it is a Womb as well. Ideally no mass will be wasted, everything used. But I suppose it may on the next opening become the poo shoot.

But I have now been thinking about how clams grow. Packman is likely not ideal.

https://en.wikipedia.org/wiki/Clam
Image Quote:

So, the desire is to be able to build up the "Clam" bigger. So that as you go you can "Eat" bigger and bigger rocks or rubble piles.

Although I have indicated that the shells will be hollow inside of the double shell, as in:

The blue areas in the double shell can be filled with air or just tubes and rooms that connect together. So the "Clamshells" can also be so arranged.

And this structure may be connectable to the Finns Notions.

So, part of the solution to NEO's is to go eat them, but also why not go to the Asteroid belt as well? And the Jupiter Trojans tend to be smaller asteroids.

https://en.wikipedia.org/wiki/Jupiter_trojan
Image Quote:
Quote:

Numbers and mass
A gravitational potential contour plot showing Earth's Lagrangian points; L4 and L5 are ahead (above) and behind (below) the planet, respectively. Jupiter's Lagrangian points are similarly situated in its much larger orbit.
Estimates of the total number of Jupiter trojans are based on deep surveys of limited areas of the sky.[1] The L4 swarm is believed to hold between 160,000 and 240,000 asteroids with diameters larger than 2 km and about 600,000 with diameters larger than 1 km.[1][11] If the L5 swarm contains a comparable number of objects, there are more than 1 million Jupiter trojans 1 km in size or larger. For the objects brighter than absolute magnitude 9.0 the population is probably complete.[15] These numbers are similar to that of comparable asteroids in the asteroid belt.[1] The total mass of the Jupiter trojans is estimated at 0.0001 of the mass of Earth or one-fifth of the mass of the asteroid belt.[11]
Two more recent studies indicate that the above numbers may overestimate the number of Jupiter trojans by several-fold. This overestimate is caused by (1) the assumption that all Jupiter trojans have a low albedo of about 0.04, whereas small bodies may have an average albedo as high as 0.12;[18] (2) an incorrect assumption about the distribution of Jupiter trojans in the sky.[19] According to the new estimates, the total number of Jupiter trojans with a diameter larger than 2 km is 6,300 ± 1,000 and 3,400 ± 500 in the L4 and L5 swarms, respectively.[19] These numbers would be reduced by a factor of 2 if small Jupiter trojans are more reflective than large ones.[18]
The number of Jupiter trojans observed in the L4 swarm is slightly larger than that observed in L5. Because the brightest Jupiter trojans show little variation in numbers between the two populations, this disparity is probably due to observational bias.[5] Some models indicate that the L4 swarm may be slightly more stable than the L5 swarm.[10]
The largest Jupiter trojan is 624 Hektor, which has a mean diameter of 203 ± 3.6 km.[15] There are few large Jupiter trojans in comparison to the overall population. With decreasing size, the number of Jupiter trojans grows very quickly down to 84 km, much more so than in the asteroid belt. A diameter of 84 km corresponds to an absolute magnitude of 9.5, assuming an albedo of 0.04. Within the 4.4–40 km range the Jupiter trojans' size distribution resembles that of the main-belt asteroids. Nothing is known about the masses of the smaller Jupiter trojans.[10] The size distribution suggests that the smaller Trojans may be the products of collisions by larger Jupiter trojans.[5]
The largest Jupiter trojans
Trojan Diameter (km)
624 Hektor 225
617 Patroclus 140
911 Agamemnon 131
588 Achilles 130
3451 Mentor 126
3317 Paris 119
1867 Deiphobus 118
1172 Äneas 118
1437 Diomedes 118
1143 Odysseus 115
Source: JPL Small-Body Database, NEOWISE data

I am hoping that the asteroid belt holds a lot of small rubble piles that the "Clams" can munch on.

Obviously, the clams could have all kinds of manipulator arms inside of them to work with the materials. Magnetics and electrostatics might also be used for manipulation.

Done.

Last edited by Void (2023-03-21 19:41:03)

Calliban · 2023-03-22 03:07:03

Void, the Pacman concept is a neat idea. One of the problems with mining asteroids is that they are often rubble piles held together by microgravity. There is nothing to push against when taking a scoop of material out of the surface. And there is no gravity to keep the scooped material in the shovel. So grabber shovels will be needed, which close around the material, taking bites out of the surface.

Your Pacman idea could be a solution, as the enclosing sphere provides an inner surface to attach manipulator arms to. It has mass, so its centre of gravity will line up with the centre of gravity of the asteroid and it will hang there. If a manipulator arm pushes against the surface of the asteroid as it takes a bite of material, it will push the two centres of gravity out of alignment and there will be a net force restoring the two to equilibrium. If the spherical shell can slowly rotate, then you can put chutes arouhd its equator into which the arms can drop material that they have bitten off the surface. Chutes will lead to ore processing facilities, which will hang outward from the outer equatorial surface of the sphere. The further the facility is from the axis of rotation, the higher the effective spin gravity. Our worker housing modules would hang many kilometres from the surface of the sphere, as humans need substantial gravity for health. Most mining would be done using remote controlled machines. Humans would only directly enter the sphere to repair machines.

The sphere has the neat advantage of catching any material that is knocked off of the surface. So ultimately, no part of the asteroid will get lost to space. Any silicate waste materials that we don't have use for, could be used as reaction mass for mass driver tugs.

Last edited by Calliban (2023-03-22 03:12:25)

Calliban · 2023-03-22 03:59:20

Far future human habitations are likely to be swarms of O'Neill cylinders, physically connected to a common hub to allow propellantless travel between them.

If our giant Oort cloud habitation sphere is able to seat O'Neill cylinders on magnetic bearings, then it need not rotate. Food producing areas can be built on towers stretching out from the sphere surface thousands of km into space. Food production doesn't care for aesthetics, so these food factories would be multishelled cylinders, with food grown on floors. Heat radiating panels would branch off of the towers rather like leaves. Electricity producing fusion reactors would be built high on the towers, allowing their waste heat to be radiated a long way from the sphere surface. I can imagine a sphere eventually looking more like a porcupine. Tall towers would strut out from its surface, with towers having agricultural pods, spaceship factories and O'Neill cylinders attached to them. A conglomeration like this could eventually house as many or even more people than now live on Earth.

The advantage that such a conglomeration provides over distributed human colonies, is that transportation between its components does not require propellant. If you want to move from one O'Neill cylinder to another, you exit at the axis of rotation. A train can then be used to travel across the conglomeration to any other point. The journey is entirely electric powered with no reaction mass being expended. The problems that conglomerations will face is that gravity will eventually become a structural burden and waste heat becomes more difficult to radiate as conglomerations increase in size. The first problem is why I proposed rotating the conglomeration. The second problem is a hard limit, because heat radiation is a function of surface area and temperature.

Alien civilisations may have already constructed conglomerations of O'Neill colonies. These megastructures could be found by looking for the infrared signatures of their waste heat. The question arises as to whether such conglomerates could be engineered to survive for geological timescales? If artificial fusion is mastered, they would have little use for stars. The gravity wells, radiated heat and dearth of volatile materials close to stars would all be a nuisance to them. They would likely favour the Oort clouds of star systems, where there are volatile rich materials and close to zero heat pollution from stars. Metals can be recycled endlessly. But all habitats would leak gas, which would eventually need to be replaced. This suggests to me that Oort clouds and Kuiper belts will eventually be favoured locations. As more and more conglomerations are built, humanity will spread by slow diffusion out through the galaxy.

Star Trek and other SciFi tends to envisage humanity as a species of planet dwellers. This shapes our visions for the future and we tend to dream of warp drives, which can take us to extrosolar planets that we can visit and settle. But this is unlikely to be our future. We imagine future life in this way because it is an extension of what we know. But our true future lies in the outer reaches of star systems and the cold wastes between the stars. Planets will actually be a nuisance to us, because their materials are stuck in gravity wells. Free space allows us to build whatever we want and move around at low energy cost. So our long term future home looks more like a swarm of habitats in free space than any colony built on a planet. Warp drives aren't as useful under that scenario, because our needs are equally well met by icy comets that are identical everywhere. This suggests that humanity will spread through the galaxy by slow migration through ice rich Oort clouds and interstellar rogues. Space itself, not planets, will be our future home. This may explain why Earth hasn't been colonised by other space faring races. They just aren't that interested in what it has to offer. Halley's comet is more useful to them.

Last edited by Calliban (2023-03-22 04:18:08)

Calliban · 2023-03-22 04:58:12

If humanity masters nuclear fusion as an energy source, then KBOs like Pluto and Charon afford us an opportunity that we wont have in free space. These bodies have low gravity and are superb heat sinks. Heat management is a really limiting factor for human space colonisation, because enormous and expensive radiator panels will be needed to dump heat into space. This means that our habitats are limited in their practical density. It is one of the reasons why O'Neill habitats were designed as hollow cylinders. They need as much radiator area as land area. If we were to atrempt to build them with internal decks, then the radiators would end up dwarfing the cylinders.

On Pluto and other icy bodies, we can break this limitation, because the surface is covered in material that could absorb huge amounts of heat. We can remove heat from a surface mounted habitat by melting nitrogen and boiling it into the air. Or we could floating our habitat on an ice covered lake and pump water through heat exchangers.

If we model Pluto as a ball of water ice some 2200km in diameter, it would take some 4.2E27 joules to heat it up from 50K, melt it and warm it to 30°C. That is 10TW for 13 million years. But the surface and atmosphere itself would radiate 7000TW into space at 300K. So we are unlikely to ever melt body. A heat flux of 7000TW, is about what would be produced by lighting 60,000 Island 3 cylinders. But on Pluto, these could be far more compact for the same land area than anything we build in free space. That has economy advantages.

Large icy bodies like Pluto, Titan, Triton and Eris, could end up being partially terraformed with thin atmospheres and ice covered seas, thanks to the waste heat from human habitats and fusion reactors on their surfaces. This is a kind of byproduct of what humans would be doing anyway. It is a kind of symbiosis, with humans providing the heat and the planet providing a liquid coolant. The thin atmospheres probably won't be breathable for humans. But they could provide enough oxygen to oxygenate the cold oceans. Alfae would use weak sunlight to fix sugars, which would form the base of aquatic ecosystems. The thin atmospheres would also provide shielding, eliminating or reducing the cosmic ray shielding needed by the habs.

The solar system has many moons and dwarf planets that could ultimately be used in this way. These worlds have some CO2, CO and nitrogen reserves. But so far as we can tell, their bulk mass is dominated by rock and ammoniated water ice. The ammonia is plant fertiliser. Any CO2 is plant food. And oxygen is secreted. It may take many millenia, but eventually algae photosynthesis and gas leakage from habitats will lead to the accumulation of an oxygen atmosphere. Humans walking on the surface would need counter pressure suits, but breathing air could be provided by compressors. We could even have floating rafts covered with plants and animals adapted to low pressure.
************

Additional: Alan Stern asserts that atmospheric pressure on Pluto could rise to 280mbar, if enough nitrogen were to sublime. This woukd be enough for liquid nitrogen to flow on its surface. That would be an excellent coolant. But I wonder how stable a 280mbar atmosphere would be on a body with only 20% of our moon's mass?
https://en.m.wikipedia.org/wiki/Pluto

Last edited by Calliban (2023-03-22 05:50:05)

Void · 2023-03-22 09:11:50

That is good stuff Calliban.

Query: "What are the smallest asteroids?"

General Image Response: https://www.bing.com/images/search?q=%2 … C3&first=1

https://www.zmescience.com/space/nasa-m … d-science/
Image Quote:

So, then by starting to munch on the little ones, perhaps a build-up progression to munching on the bigger ones.

So, for many cases, perhaps we should study the notions of this recent set of notions:
https://www.frontiersin.org/articles/10 … 45363/full

https://newatlas.com/space/space-habitat-ring-plan/
Image Quote: ?url=http%3A%2F%2Fnewatlas-brightspot.s3.amazonaws.com%2F0c%2Fe7%2F1bf75795423681c18b5f25c5abfd%2Ffea-asteroid-base.jpg

So, perhaps the above concept and "Pack-Man Clam" can be merged for startup methods, and over time the asteroid eater may create a harder Shell(s) for itself, or "Child" copies.

And yes "To Infinity and Beyond!", Well, Kuiper/Oort/Interstellar anyway.

Done.

Last edited by Void (2023-03-22 09:26:31)

Calliban · 2023-03-22 09:53:15

It is the way of things to start small and build up scale over time. It is the way every human enterprise has worked up to now.

When I started this thread a few years back, I had in mind that we would be tunnelling into and spinning up asteroids. A net or sack of strong fibres would be wrapped around it like a cocoon, to prevent it from flying apart. My rational was that this would allow a shirt sleeve environment for humans to work in.

Three years later, what I have learned tells me that my original idea was unlikely to be the best practical means of asteroid mining. Most asteroids are rubble piles. Tunnelling into them won't work. Spinning them up is pointless. Humans won't be breaking these things apart with pickaxes. They will be remotely controlling machines that do it for them. Instead of trying to inhabit asteroids, we want the most of efficient way of taking asteroids apart, so that we can process their materials into habitats and tools that we can actually use.

I think your pacman idea is a good one. It is effectively a platform that we would use to completely enclose an asteroid and mine it using manipulator arms. If the surface is loose and material flies off when we try and catch it, the shell of the sphere will prevent it from flying off into space. Any dislodged material will either settle on the inside of the sphere, fall by spin gravity down the chutes or fall back onto the surface of the asteroid.

If we start with a pacman that is say 100m in diameter, then there are plenty of NEOs that we can deploy it to. When a target asteroud is exhausted, we take whatever waste slag is left over and use it as reaction mass to send our pacman to a new asteroid. A 100m diameter stony asteroid, would mass some 1.3 million tonnes. A 50m diameter body would mass 170,000 tonnes. That is plenty of material to get started with. We want our pacman to be able to handle a variety of rock sizes and geometries. Whilst there are a lot of small NEOs, not all of them will be on economically favourable orbits. So our strategy needs to be adaptable.

Void · 2023-03-22 10:27:26

I recall your notion of a ring around an asteroid with arms that could pluck materials. That is the first notion of it that I am aware of.

Reaction mass is a good notion, but we also have photons either from the sun or remote lasers, and also sailing a magnetic field on the solar wind.

Generally these two will favor moving objects away from the sun and so away from the Earth, which may be beneficial as we don't want them in the Earth's path anyway.

Special materials in small quantities could be moved back to where the bulk of the people will live.

Done.

Void · 2023-03-22 10:47:18

So, maybe in time laser propulsions: https://www.bing.com/videos/search?q=Is … M%3DHDRSC4

And also even if not being pushed by photons, the delivery of dense energy to a asteroid eater. Better energy density than just solar panels.

Of course, death rays? Well, we have nukes and poisons, somehow, we haven't killed everyone, YET.

Lasers that are contemplated for sending probes to Proxima Centauri, may have a more solar system local application.

Platforms that have already used all the local ores, might then send laser power to other stations that would need it either for travel or ore processing/manufactuing.

Done.

Void · 2023-03-22 11:12:28

So, as far as depletion of volatiles, I anticipate that it may be true that where the solar wind impacts the interstellar medium, a form of condensation may occur. Maybe even onto comet like objects. Some of this would be exchanged between stars.

Of course if the Universe is expanding forever because of Dark Energy coming from black holes, That would not be a forever thing, also if the sun goes white dwarf, that is then an end but a big puff of materials before white dwarf.

I personally hold a small fraction of speculation towards a more eternal universe where perhaps somehow matter is eventually created from energy, perhaps dark energy.

But no, I have no evidence of that, (yet).

And I guess I don't so much care, as it is silly to worry about things so far and long away. Me being very mortal, and short lived.

Done.

Void · 2023-03-22 11:32:13

So, I seem to recall, PhotonBytes2023 likes the idea of digging holes in Mars with impactors.

Processing a large NEO, you could eventually hit Mars with some of the waste materials to dig such a hole if that is desired. Of course the bulk of the materials would build space habs and associated structures.

This one is probably overkill: https://en.wikipedia.org/wiki/1036_Ganymed
Quote:

1036 Ganymed, provisional designation 1924 TD, is a stony asteroid on a highly eccentric orbit, classified as a near-Earth object of the Amor group. It was discovered by German astronomer Walter Baade at the Bergedorf Observatory in Hamburg on 23 October 1924, and named after Ganymede from Greek mythology.[1][2] With a diameter of approximately 35 kilometers (22 miles), Ganymed is the largest of all near-Earth objects but does not cross Earth's orbit. The S-type asteroid has a rotation period of 10.3 hours. In October 2024, it is predicted to approach Earth at a distance of 56,000,000 km; 35,000,000 mi (0.374097 AU).[15]

Image Quote:
Quote: [img]Orbit of Ganymed (blue), with the inner planets and Jupiter (outermost).[/img]

So, if having gotten water and Carbon from other NEO's you worked with 1036 Ganymed, you could drop your (Waste Rock) on Mars to dig holes deeper and deeper, probably in Hellas. You could size the impactors and possibly give them special qualities, such as length and diameter, porosity.

Image Quote: 001036-asteroid_shape_model_%281036%29_Ganymed.png

That would be one heck of a cycling spaceship. Almost perfect!

I think a way to deal with an object like this is to make a half shell dome and pick materials off the surface, and tuck them into connected ballast chambers so that eventually you have enough gravitational attraction to make it stick to the object well enough to dare more powerful moves.

Maybe like this, so that you use mechanisms to keep loading ballast into a radiation shield, making the situation more suitable for human visits.

Done.

Last edited by Void (2023-03-22 19:35:19)

Void · 2023-03-22 19:06:08

I request your patience Calliban, as I am using your topic rather hard. I am wondering about magnetism in an "S" type asteroid.

https://physics.stackexchange.com/quest … ic%20field.
The orbit of Gaspra is not that obviously good, but my interest is if these asteroids can have enough magnetic material for a superconductive magnetic field make a hab stick to the "S" asteroid.
Image Quote:
Image Quote:
Animation of Galileo's trajectory from 19 Oct 1989 to 30 Sep 2003
Galileo (Violet)· Jupiter (Green)· Earth (Dark Blue)· Venus (Green)· 951 Gaspra (Yellow)· 243 Ida (Light Blue)

We generally turn up our noses about "S" type asteroids such as "Ganymed" and "Gaspra", as we think to have water and metals which will not be with "S" asteroids to a large extent. But if we can "Eat" things similar to Ryugu and Bennu, then we may bring what is needed to these asteroids.

Ryugu:
https://en.wikipedia.org/wiki/162173_Ry … 20asteroid.
Image Quote:
Quote:

Sample analysis results
After the initial description (phase-1), part of the sample was distributed to the Hayabusa2 Initial Analysis Team, consisting of six sub-teams, and two Phase-2 curation institutes at Okayama University and JAMSTEC Kochi Institute for Core Sample Research.[36]
In September 2022 the Hayabusa 2 initial Analysis Stone Team announced the results of their study, which includes:[37]
Ryugu samples contain grains that were formed at high temperatures above 1000°C, which formed close to the sun and were later transported towards the outer solar system.
The samples are soft enough to be cut with a knife and the samples preserve the magnetic field like a hard disk.
A simulation of the formation was performed, which showed that the parent body of Ryugu accumulated 2 million years after the formation of the solar system. It heated up to 50°C over the next 3 million years, resulting in reactions of rocky material with water. In these reactions anhydrous silicates became hydrous silicates and iron became magnetite. The 100 km large parent body was then destroyed by a <10 km large impactor, with an impact speed of about 5 km/s. Ryugu then formed from material far from the impact.
Origin from the outer Solar System
The deuterium-rich and nitrogen-15-rich isotopic compositions of fine-grained minerals and organics suggests that the parent body of Ryugu formed in the outer Solar System.[38] Titanium, chromium and molybdenum isotopic anomalies provide more evidence that ties Ryugu's origin to the outer Solar System.[39]
Based on preserved magnetism in the samples researchers concluded that the parent body of Ryugu was likely formed in the darkness of nebular gas.[37]
Liquid water and aqueous alteration
Carbonated liquid water was discovered in one crystal. The water contained salts and organic matter. The liquid water was found inside a hexagonal iron sulfide crystal. The carbon dioxide was likely CO2-ice (dry ice) inside the parent body. The water ice melted soon after the parent body formed and the CO2 dissolved into the water.[37]
Crystals "shaped like coral reefs" were found. These crystals likely formed in liquid water, which was once present in the interior of the parent body.[37] The parent body had a dryer surface and a wetter interior. After the collision of the parent body with a smaller asteroid, the interior and surface material were mixed. Today Ryugu has both interior and parent body surface material on its surface.[37]
An international team found particles in the samples that contained small amounts of material unaltered by water. The team found about 0.5 vol% of anhydrous silicates. The isotopic analysis of the magnesium-rich olivine and pyroxene in the sample suggests that two types of high-temperature objects accreted onto the surface of Ryugu: amoeboid olivine aggregates and magnesium-rich chondrules.[40]
Organic molecules
Aliphatic carbon-rich organics associated with coarse-grained phyllosilicates were found. Such an association has not been observed in any meteorite study and could be unique to the asteroid Ryugu.[38]
In samples retrieved on Ryugu from the Japanese Hayabusa2 spacecraft, scientists discovered 20 different amino acids, the building blocks of life.[41]
In March 2023, scientists announced that uracil, one of the four nucleobases in RNA, as well as vitamin B3 (niacin), a key cofactor for metabolism,[42] were detected in samples retrieved from Ryugu.[43] Unlike in previous instances when nucleobases and vitamins were also found in certain carbon-rich meteorites, the contamination by exposure to the Earth’s environment was ruled out as the samples were collected directly from asteroid and delivered to Earth in sealed capsules.[42] The findings corroborated the increasing evidence that the building blocks of life originated in space and were originally delivered to Earth billions of years ago by meteorites.[42]
Similarities to CI chondrites
NanoSIMS-based analysis at the Carnegie Institution found that the Ryugu samples contained grains older than the solar system. The abundance and composition of these presolar grains were similar when compared to presolar grains in CI chondrites.[44] Researchers using the particle accelerator in J-PARC, used Muon beams to analyse the chemical composition of the samples. The researchers found a similar composition when compared to CI chondrites, but a 25% lower oxygen abundance relative to silicon for the Ryugu samples. The oxygen excess in meteorites might come from contamination after they entered earth's atmosphere.[45]

Green is Ryugu and Dark Blue is Earth. So the solar wind may help to move the materials out to a "S" asteroid.

Bennu:
https://en.wikipedia.org/wiki/101955_Bennu
Image Quote:
Click the following link for a better view:
https://upload.wikimedia.org/wikipedia/ … _Orbit.png
Quote:

Water
Predicted beforehand,[49] Dante Lauretta (University of Arizona) then stated that Bennu is water-rich- already detectable while OSIRIS-REx was still technically in approach.[50][51]
Preliminary spectroscopic surveys of the asteroid's surface by OSIRIS-REx confirmed magnetite and the meteorite-asteroid linkage,[52][53][54] dominated by phyllosilicates.[55][56][57] Phyllosilicates, among others, hold water.[58][59][60] Bennu's water spectra were detectable on approach,[53][61] reviewed by outside scientists,[62][40] then confirmed from orbit.[37][63][64][65]
OSIRIS-REx observations have resulted in a (self-styled) conservative estimate of about 7 x 108 kg water in one form alone, neglecting additional forms. This is a water content of ~1 wt.%, and potentially much more. In turn this suggests transient pockets of water beneath Bennu's regolith. The surficial water may be lost from the collected samples. However, if the sample return capsule maintains low temperatures, the largest (centimeter-scale) fragments may contain measurable quantities of adsorbed water, and some fraction of Bennu's ammonium compounds.[65]
Further information: Asteroidal water

So, in working with a "S" asteroid, I would want to know its magnetics, and if it is fractured. If it is, then you might jack the pieces apart to provide a habitat space.

To place a half shell dome, on a "S" asteroid you might start with magnetics, and then try to set anchors into the regolith or if possible, into a large slab of rock. Then fill the double-half-Shell with regolith for environmental upgrading, and to make the shell have weight in the tiny gravity field.

Like this:

Using the regolith of the "S" asteroid construct what is needed. If it turns out that it is desired to dig holes into the surface of Mars then arrange for it.

Doing all of this may get dangerous asteroids out of orbits we don't want them to be in. At first small ones but later maybe big ones.

Done.

Last edited by Void (2023-03-22 19:49:27)

Void · 2023-03-22 20:22:55

Well, maybe it is ok to put this here:

"Building Bricks on the Moon from Potatoes, Fraser Cain"

https://www.bing.com/search?q=Building+ … A0&PC=U531
Quote:

Building Bricks on the Moon from Potatoes
4.5K views · 9 hours ago
YouTubeFraser Cain

I presume this could probably apply to asteroid regolith.

Done.

Last edited by Void (2023-03-27 20:35:09)

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