Colonizing / terraforming small asteroids

Calliban · 2020-02-10 10:57:17

The spider sounds like a good idea, especially if it can be automated. A few issues that might be problematic:

1. Very small asteroids have negligible gravity and it might be difficult for the spider to get enough traction to walk across the surface.
2. Drawing molten basalt through bushes requires gravity.
3. What would power the spider? It could have a giant solar array strapped to it's back or maybe a couple of kilo power units.
4. The spider would need a means of picking up surface rocks and feeding them into the electric melting furnace. Not sure how that could be done.
5. The spider would need to coat each fibre with a polymer coating to prevent frictional damage. Presumably, that would need to come from Earth. On the plus side, it probably only need be a few atoms thick.

tahanson43206 · 2020-02-10 16:18:24

For Calliban re #151

For SpaceNut re the flying thread layers concept ...

SpaceNut's idea was to wrap the cocoon, not by walking on the surface, but instead by flying around it. SpaceNut's specific idea that I am picking up on was to take advantage of the asteroid's natural rotation.

However, if my earlier post was not clear, I'll try to add some details that might help.

Plus! I'm definitely hoping a few questions I've come up with will be interesting enough to justify a moment or two of consideration.

I'd like to suggest separating the process of creating basalt thread from the problem of wrapping a cocoon. The robotics involved are significantly different and (in my opinion) it is better to keep the two development teams separate from each other.

Drawing molten material should not require gravity, so I'm probably missing something important. I would have expected hot molten material to flow out of a small opening in a melt pot and be taken up by a takeup reel as the melt solidifies in space. The diameter of the thread is unimportant, because the application is to surround a rubble pile. The cleanliness of the thread is not important, and in fact it would be counter-productive. The more little whiskers of molten material that can be encouraged on the thread the better, because the application is to snare fine powder in the exterior layers of the asteroid and to immobilize them with the least amount of thread possible.

The spider would be powered by solar energy, so each reel unspooling thread would be guided in its motion relative to the asteroid by tiny ion engines.

As a happy coincidence, I saw an article recently about the development of tiny ion engines for satellite station keeping. I'll try to find the reference.

The spider would be extremely small, and its power requirements would be small. it's mission would be to pay out thread from a reel, and the energy required to do that would come from small solar power panels.

The thread CREATION process would NOT be done by a spider, but instead would be done by a completely different robotic system, designed to pull basalt raw material from asteroids rich with that material.

The spiders unspooling thread would be working with metal rich asteroids to be harvested.

I am unsure why a coating is needed for the thread, because its life is (presumably) limited to coiling up on a takeup reel, and then unspooling onto an asteroid to be wrapped for shipment to a major processing center, or (the source of funding mentioned earlier) to be wrapped for acceleration so as to miss the Earth.

If the physical properties of the thread are such that it sticks to itself when wound onto the takeup reel, then I could certainly understand the need for a coating.

If this concept is to be developed by Open Source development teams, there is a need for a protocol that I am not currently familiar with to coordinate the work. In an Open Source development environment, every contributor would have full and equal access to all work products.

The challenge would be to find funders willing to invest in one or more teams to actually build and deploy the systems.

Edit#1: It would be helpful if someone who is able to post on the Forum can explore opportunities to secure funding from entities that are set up to protect the Earth from asteroids. At present I know of at least on non-profit organization, and I presume (but do not know) there must be elements of national governments who have at least one person assigned to researching the problem.

(th)

Last edited by tahanson43206 (2020-02-10 16:22:03)

SpaceNut · 2020-02-10 19:09:55

One could also tether the walking machine to a line that encircles the asteriod as well and use it like a climbers rope securing for safety as you move just anchor it in a few places.

So it looks like we have 3 methods to make this making of a basalt woven bag or caccoon...
Each have there good and bad for cost and design but none will happen without funding to work out the hardware.

tahanson43206 · 2020-02-10 20:08:20

For SpaceNut re #153 ... building on your note about funding...

The hardware will certainly be challenging. At the same time, I'd like to point out that software development will be a major part of the work effort to build and deploy a complete asteroid capture system using this technology.

What I am "seeing" right now is a swarm of small ion thruster equipped devices with small(ish) reels of basalt thread to deploy. These would be similar to the swarms of drones which may be seen in operation in YouTube videos. I like this example, because it illustrates independent coordinated flight.

https://www.youtube.com/watch?v=3TYqTtmWhx4

The hardware for the thread extruder would (presumably) be significantly more complex, because it would have to harvest input material from a suitable asteroid, heat it to the needed temperature, and coordinate the extrusion from the heating chamber with the action of the takeup reel.

Calliban has cautioned that gravity may be required for successful extrusion of basalt thread, and I am hoping forum members may be able to comment on that issue, one way or the other. There may have been research done on-orbit in the ISS or perhaps on Mir.

The question to be answered is whether hot melt can be driven out of the melt chamber in a controlled way that allows for manufacture of thread.

In any case, a set of work projects that would be needed to design, build and deploy an asteroid cocoon capture system will include both hardware development and software, and of the two, I would expect substantially more of the investment will go into the software.

(th)

SpaceNut · 2020-02-10 20:27:39

We have these topics which had Nasa in the wings for a boulder on up side to bring to the moon which still could happen.
NASA's Asteroid redirect/retrieval mission; should it be cancelled?
SLS and what asteriod will we go to

Saving the Earth - the B612 Foundation

Calliban · 2020-02-11 06:03:31

I will respond in more detail later. The required thickness of fibres is an interesting question. Why would they need to be micrometre sized? Why not mm sized? Why not as thick as rebar? The larger the fibre, the easier fabrication will be, as it is much easier to design bushings for coarse fibres.

The coating is there to prevent stress fractures due to surface interactions. Basalt fibres are inherently brittle and the critical crack length for propagation through the material is extremely small. So small surface features can result in brittle fraction of the fibre under stress.

Gravity is needed to drain the melt through the bushings. We could simulate gravity using rotation. But it complicates design somewhat.

tahanson43206 · 2020-02-11 09:43:25

For Calliban re #156

For SpaceNut ... thanks for the B612 link!

Thickness (as you have shown) can vary depending upon the application. I don't know where the sweet spot may turn out to be, but for a cocoon it would need to be somewhat less than rebar << grin >>. The pictures of actual on-Earth basalt thread manufacture showed coils of thin material coiling up on reels which appeared to be about half a meter wide and with a starting diameter of perhaps 10 centimeters.

It is entirely possible that the thin coating you've described may be essential to give the fiber the resilience to survive coiling.

The need for the coating does complicate the design, but if its needed then that need has to be addressed.

The matter of gravity seems important to try to overcome.

A process that ** could ** eliminate the need for gravity is pressure inside the heating chamber. The melt could be expelled from a nozzle the way melted plastic is expelled from the nozzle of a low-tech 3D printer. In that case, the pressure that forces the melted material out of the nozzle is provided by a tractor mechanism that exerts force on the incoming raw filament. That force is considerable (in relative terms) because the filament has to be forced through a constriction. The reason this works is that the filament is heated by the nozzle so it flows as a viscous liquid out onto the work surface where it solidifies rapidly.

I hope ways can be found to address the practical difficulties of implementing the concept under discussion here.

For SpaceNut .... funding is available for ideas which have no substance. The funding is provided to see if the idea can hold up to the rigors of practice.

The payoff for the funder can be significant, if a promising idea turns out to have merit.

My understanding is that a rule of thumb for first stage investing is that 1 project succeeds out of 10 that are attempted.

In the present case, we have the luxury of exploring the potential of an idea with actual on-Earth examples to study, and a substantial amount of on-orbit experience accumulated by humans from multiple nations over decades.

it should be possible to gain a reasonable level of confidence that ** this ** idea is practical without investing more than some time and a bit of effort.

I have no doubt that JPL (as just one example) could develop an independent flying thread deploying robot device able to operate as part of a swarm, to build up a cocoon around any asteroid.

I am less confident that there exists on Earth today an organization capable of designing a basalt thread extruder that could operate without gravity.

It would be a nice surprise to learn that someone, somewhere on Earth today, is working on that very problem.

Edit#1: A topic to explore is: 3D printer basalt fiber

If basalt can be 3D printed the resulting objects would have interesting and potentially useful properties.

Edit#2: A Google search for "want to buy basalt thread" yielded 2 million results

The top page is filled with citations of vendors represented by Alibaba.com.

The images shown of basalt products, from thread to rebar, are supplemented by a link to more.

There are two images of what may be the same 1 kg spool of basalt thread offered on eBay for $37.52 <<== Price on 2020/02/11

I would deduce from this result that a reasonable strategy for a funder wanting to find a supplier of basalt thread willing to consider how to produce such thread in space would be to assume Asia is where the action is, and to seek out potential partners there.

Here is a version of the story I had not anticipated. From: https://www.cruisersforum.com/forums/f4 … 11158.html

Basalt Fiber for construction of yachts
I am wondering why we are the only yacht builders to use basalt fiber in construction of yachts.
it is a wonderfull material non toxic , the source is renewable , fossil fuels are not needed to manufacture it.
It is stronger than E glass
It is noise dampening contrary to glass and carbon fibre .
It does not burn.
It infuses better than both E glass and carbon fiber.
You can read some more on it in the link below
CompositesWorld.com - Composites Technology - Basalt Fibers: Alternative To Glass? - August 2006
https://www.compositesworld.com/ct/issu … ust/1400/3

Edit#3: A search for 3D printers that use basalt came up with this:
https://www.3dprintingmedia.network/ani … -printing/

We (in the forum) may have seen this before, in the 3D Printer topic. The shapes produced have interesting properties, including transparency to electromagnetic radiation, so they can be used in situations where radio signals are part of the design.

(th)

Last edited by tahanson43206 (2020-02-11 18:47:35)

tahanson43206 · 2020-02-11 19:27:17

For Calliban (others welcome to add/comment) ...

Apophis has come up for discussion in the past. I was curious to know how much thread would be required to wrap the asteroid.

The dimensions of the asteroid are estimated as 450 meters by 160 meters, and the shape is estimated as a football (ie, prolate spheroid).

I visited Wolfram to get a sense of the math involved, and then found a handy math calculator.

https://planetcalc.com/149/

Ellipsoid
80 meters Semi-axis a a semi-axis (radius) length
80 Semi-axis b b semi-axis (radius) length
225 Semi-axis c c semi-axis (radius) length
Calculation precision
Digits after the decimal point: 5
Volume
6031857.89489 cubic meters
Surface area (approx.)
185960.88 square meters

The length of thread needed would be a function of the spacing needed.

A caterpillar in Nature wraps multiple threads around itself to enter hibernation.

An asteroid composed of loose rubble would (presumably) require more than one layer of thread if the thread were wound as a caterpillar winds its cocoon.

However, if threads are laid along the long axis of the "football" as well as around the circumference of the slices cut through the long axis, it might be possible to insure that loose material is constrained by the net so that less than complete coverage is needed.

The intention would be to apply thrust to the object (presumably along the long axis) so the thread woven over the surface would need to be strong enough to withstand expansion forces as the loose material tries to escape.

Edit#1: The next development I would like to see for this topic is computation of the amount of thread that would be needed to cover Apophis completely in a single layer drawn laterally as is done by a caterpillar when creating a cocoon. The actual amount of thread needed may be less, if the material comprising the asteroid can be constrained by thread which is near but not immediately adjacent to nearby thread.

On the other hand, thread drawn in the longitudinal direction will require additional thread. There may be a sweet spot for the total amount of thread needed for a given asteroid, depending upon the properties of the thread itself, and of the material at the surface of the asteroid.

(th)

Last edited by tahanson43206 (2020-02-12 08:48:27)

tahanson43206 · 2020-02-16 11:02:04

For Calliban re Cocoon idea for Apophis ...

Do you have any interest in trademarking the term Calliban's Spider, as described in this post:
http://newmars.com/forums/viewtopic.php … 93#p165093

If not, I'd like to proceed with development of the idea as an Open Source design, NOT subject to patent by any person or entity.

Edit#1: I sent the following email to Anisoprint:

Hello.
The purpose of this inquiry is twofold:
First, is the 3D printable basalt fiber material developed by Anisoprint available for purchase in the form of a roll?
If so, please provide a link to the sales web site.
Second, is it possible for Anisoprint to make basalt fiber thread out of asteroid material?
The conditions to be faced by an automated thread manufacture system deployed at a suitable asteroid are significantly more challenging than would be true on Earth, and I am sure the conditions for manufacture on Earth are quite challenging.
***
This inquiry comes on behalf of the NewMars.com/forums website. The forum is a project of the Mars Society which is based in the United States, and has chapters in several countries outside the US.
There is a discussion of wrapping the asteroid Apophis in a cocoon made of basalt fiber. This is a long term project which would be carried out by robots under remote human direction as Apophis completes multiple revolutions of the Sun. Eventually the cocoon will be strong enough to enable Apophis to be given "normal" propulsion by chemical rockets.
This technique could (of course) be used to protect the Earth from threatening asteroids in the future.
The discussion of a cocoon for Apophis is taking place in the topic at the link below:
http://newmars.com/forums/viewtopic.php … 59#p165159

Through this contact the chances someone at Anisoprint will become aware of the cocoon idea are increased from zero to infinitesimal.

(th)

Last edited by tahanson43206 (2020-02-16 11:45:49)

SpaceNut · 2020-02-16 12:43:34

Not sure that we are ready but maybe GW could chime in for business patents...

Calliban · 2020-02-16 16:52:06

tahanson43206 wrote:

For Calliban re Cocoon idea for Apophis ...
Do you have any interest in trademarking the term Calliban's Spider, as described in this post:
http://newmars.com/forums/viewtopic.php … 93#p165093
If not, I'd like to proceed with development of the idea as an Open Source design, NOT subject to patent by any person or entity.
(th)

It's all yours Tahanson. I will be interested to see what you turn up.

tahanson43206 · 2020-02-16 18:10:13

for Calliban re #161

Too bad << grin >> "Calliban's Spider" has a nice ring to it.

(th)

Calliban · 2020-02-17 06:25:16

tahanson43206 wrote:

for Calliban re #161
Too bad << grin >> "Calliban's Spider" has a nice ring to it.
(th)

In the past, we spoke about the option of mounting a rotating habitat at one of the poles of an asteroid. The gravity on asteroids is so weak that the loading on any bearings would be negligible. Even on a relatively large NEA like Eros, a hab weighing a thousand tonnes would weigh only about 1 tonne. For Apophis, it would be no more than a hundred kg.

What this means is that if we needed artificial gravity to draw basalt fibre, it isn't an insurmountable challenge. We could manufacture and wind the fibres onto spools that could then be loaded onto the spider robots, which would then deploy it. If we are able to chemically process surface materials in the hab, the spiders could be propelled by cold gas thrusters, using oxygen propellant for the cocoon idea. Alternatively, the spiders could be battery powered and ballasted with surface material to allow them to achieve traction against the asteroid.

Another option would be to attempt to weave the fibre into hexagonal sections (within the hab) that then be clipped together to form a net around the entire asteroid. This might simplify the EVA activity, as it can then focus on attaching the edges of pre-formed sheets of fibre.

Last edited by Calliban (2020-02-17 06:37:18)

tahanson43206 · 2020-02-17 07:36:01

For Calliban re #163

Thanks for continuing to support the concept we are tossing around here! I have a bit of energy left over which I can put to use promoting your brand, the NewMars forum, and the idea itself.

Before I go charging off to promote anything, I'd like to confirm that you are determined to give up your association with Scotland.

I wasn't kidding when I said that Scotland has a much more powerful association with brilliant engineering than does England, in the minds of Americans for sure, and perhaps other cultures as well.

You may not be brilliant (after all, few of us are), but you CERTAINLY are an engineer, and one with street creds.

Any chance you can allow yourself to restore the origin you started out with?

I can proceed either way, but you would provide a lot more wind for my sails by restoring the original origin.

***
Regarding the spinning asteroid and the well placed "thread factory" .... I ** like ** the sounds of it, and can easily imagine it will inspire creative young engineers with computer animation skills.

I agree with (and like) your ideas for the spiders. You may have missed my earlier mention of new tiny ion thrusters that have become available. I'd have to dig a bit to find the article where that announcement first appeared, but I'm guessing (if he is willing) SpaceNut could find it faster than anyone else.

In any case, battery power for the spiders makes a LOT of sense to me, because they are going to be performing intricate maneuvers in coordination with many of their fellows, and the least external encumbrance they must suffer, the better.

Earlier SpaceNut had the idea of taking advantage of the natural rotation of the asteroid to facilitate wrapping, and I think that mental model will hold up over time. Thus, we can envision many (? hundreds ?) of these little robots quietly (in vacuum of course) delivering kilometer after kilometer of fine basalt thread as they wind around the victim (er, asteroid).

The ghoulish image of this operation (it just occurred to me) ** should ** appeal to the younger set, so a line of cartoon books (? comic books / graphic novels ?) could develop the idea.

***
Louis, if we can pull you into this discussion, your fertile imagination may be able to add something that would not have occurred to me!

Edit#1: Calliban ... have you ever been known to wear a yellow t-shirt? Just checking << grin >>

(th)

Last edited by tahanson43206 (2020-02-17 07:38:48)

Calliban · 2020-02-17 11:04:10

Tahanson, the place I am from on this forum is where I am living and working at this time. As an engineer, I have moved around a bit in my career. I have updated my profile accordingly.

In terms of ancestry, I am a mixture of Scottish, English, Welsh and Irish. I'm not sure how much difference that makes in terms of who I am or what I can do as an engineer. All of these places have had their fair share of engineering and scientific genius. Both England and Scotland have been the birth place of plenty of pioneering engineers and scientists. Remember that England is where the industrial revolution started, but the mines, mills and looms of Lancashire would have included people from all over the British Isles.

The idea of a clear separation between Scottish, English and Welsh engineers and scientists is not very realistic, because for most of the past 300 years people have moved about quite a bit and have tended to work in partnership with other engineers around them. For example, Newcomen (English) developed the first practical steam engine for pumping out mine water. Watt (Scottish) in partnership with Boulton (English) and working in Birmingham developed the steam engine into something efficient and powerful enough to be mobile (on rails). Much progress in steam technology was also made by Trevithick (English / Cornish). Faraday (English) was a pioneer of electricity and magnetism and his work provided the foundations for Maxwell's (Scottish) more comprehensive work on electromagnetic theory. Maxwell was educated at Cambridge University. Alexander Fleming (Scottish) is credited with the discovery of penicillin. Yet it was his team at Cambridge University that did the work.

I don't think I am being arrogant in saying that Britain, more than any other country, made the modern world into the technological society that it has become. Can I single out any specific part of Britain as being more or less significant in that process than others? I would have to say that the Irish probably did less than the rest of the British Isles in making the modern world. But Belfast has been a prominent centre of engineering for centuries and it is here that some of the great ocean liners were built, including the Titanic. Scotland has always had excellent technical universities and until the 1970s, manufacturing dominated the local economy. England has always dominated the world in scientific and engineering qualification, with universities like Oxford, Cambridge, Kings College, Imperial college, Durham, Birmingham, being unsurpassed anywhere in the world.

Last edited by Calliban (2020-02-17 11:11:43)

Terraformer · 2020-02-17 11:34:27

I don't think using thrusters would work. Even with the low delta-V involved, going around an asteroid hundreds to thousands of times will use up propellent pretty fast.

How strong, or tight, does the netting have to be? Is it just to keep rubble piles together?

Calliban · 2020-02-17 11:34:59

tahanson43206 wrote:

In any case, battery power for the spiders makes a LOT of sense to me, because they are going to be performing intricate maneuvers in coordination with many of their fellows, and the least external encumbrance they must suffer, the better.
Earlier SpaceNut had the idea of taking advantage of the natural rotation of the asteroid to facilitate wrapping, and I think that mental model will hold up over time. Thus, we can envision many (? hundreds ?) of these little robots quietly (in vacuum of course) delivering kilometer after kilometer of fine basalt thread as they wind around the victim (er, asteroid).
The ghoulish image of this operation (it just occurred to me) ** should ** appeal to the younger set, so a line of cartoon books (? comic books / graphic novels ?) could develop the idea.
***
Louis, if we can pull you into this discussion, your fertile imagination may be able to add something that would not have occurred to me!
Edit#1: Calliban ... have you ever been known to wear a yellow t-shirt? Just checking << grin >>
(th)

Is there any reason why the deployment of the fibre cannot be done by a long arm that is mounted at the north pole of the asteroid say? The arm can be mounted at a fixed point and equipped with flexible joints that allow it to deploy cable all the way around the asteroid without detaching from its base. No propellant needed. Not unlike the old space shuttle arm, but in this case, longer with more joints and equipped with a cable spool. That way, you need not be concerned with batteries or moving around the asteroid. Solar power can come from a solar panel that tracks the sun. The arm could be equipped with electrical or gas powered actuators (hydraulics won't work in zero-g).

Terraformer wrote:

I don't think using thrusters would work. Even with the low delta-V involved, going around an asteroid hundreds to thousands of times will use up propellant pretty fast.
How strong, or tight, does the netting have to be? Is it just to keep rubble piles together?

Quite right. If you are talking say a thousand circuits of the asteroid at even a few m/s delta-v each, the propellant mass will rival the mass of the fibre.

Asteroids are basically shattered rocks. It wouldn't be practical to spin (for artificial gravity) or pressurised any cavities we dig within them, without prestressing cables.

Last edited by Calliban (2020-02-17 11:46:35)

tahanson43206 · 2020-02-17 13:31:10

For Calliban re #165

For SpaceNut re topic ...

For Terraformer re #166 ... Thanks for pitching in on the topic! I thought it had legs when Calliban started it, and your support adds nicely!

For Calliban ... OK << grin >> I'll drop the focus on Scotland ... your reminder of the proud history of the British Isles was most welcome. I enjoyed seeing so many familiar names placed in context as you did!

It's a bit cumbersome introducing you as an engineer from Upper England, but that'll work ...

For SpaceNut ... speaking of introductions ... There is a chance a young academic may take a look at this topic in the next few days.

I'm hoping he will find the idea of wrapping a cocoon around Apophis intriguing. I understand his field is aerospace engineering with a specialty in robotics.

For Calliban ... I printed out the statistics for the dimensions of Apophis in a recent post. The asteroid is (very roughly) football shaped (American football).

Your idea of spinning from an arm from one (or both) of the ends makes sense to me, and I agree that it is conceptually simpler than deploying spiders which would be free flying. More than one arm could be deployed from each end. In fact, as I think about it, that is EXACTLY the model provided by nature, for laying a cocoon.

Edit#1: (For Calliban) ... will the rotation characteristics of the object have an effect on your design for the thread deploying arm?

(th)

Last edited by tahanson43206 (2020-02-17 13:46:59)

Calliban · 2020-02-17 14:17:55

tahanson43206 wrote:

For Calliban re #165
For SpaceNut re topic ...
For Terraformer re #166 ... Thanks for pitching in on the topic! I thought it had legs when Calliban started it, and your support adds nicely!
For Calliban ... OK << grin >> I'll drop the focus on Scotland ... your reminder of the proud history of the British Isles was most welcome. I enjoyed seeing so many familiar names placed in context as you did!
It's a bit cumbersome introducing you as an engineer from Upper England, but that'll work ...
For SpaceNut ... speaking of introductions ... There is a chance a young academic may take a look at this topic in the next few days.
I'm hoping he will find the idea of wrapping a cocoon around Apophis intriguing. I understand his field is aerospace engineering with a specialty in robotics.
For Calliban ... I printed out the statistics for the dimensions of Apophis in a recent post. The asteroid is (very roughly) football shaped (American football).
Your idea of spinning from an arm from one (or both) of the ends makes sense to me, and I agree that it is conceptually simpler than deploying spiders which would be free flying. More than one arm could be deployed from each end. In fact, as I think about it, that is EXACTLY the model provided by nature, for laying a cocoon.
Edit#1: (For Calliban) ... will the rotation characteristics of the object have an effect on your design for the thread deploying arm?
(th)

Any irregular asteroid will tend to spin with its shorter axes at the poles. The only complication I can foresee is that the arm will not be in continuous sunlight. That may limit the rate at which fibre is deployed.

One thing that will be needed is at least one airlock. The cocoon will need to spin around this, as it will not be possible to install it afterward, as it would require cutting through the fibres.

Last edited by Calliban (2020-02-17 14:39:20)

SpaceNut · 2020-02-17 15:44:26

1. The walking complete factory weaving blanket was a concept put forth after seeing the walking habitats on Antartica in that it combined automated mining, processing and weaving threads into sheets as it walked it would payout the blanket onto the surface as it went.

2. the cocoon item with to bring the thread to orbit and then pay it out as staked to the surface as it orbited the asteriod. Maybe using multiple orbits to sort of weave the layers as it gets placed, leaving the manufacturing factory in a stable location on the surface.
It would seem that some sort of variation of the skycrane concept for unrolling the thread or blanket from orbit once there. With fuel for the craft being the issue.

3. manufacture spools of threads that are lobbed once anchored to the surface to travel around the asteriod meant to unspool as it goes around as thrown from the surface.

tahanson43206 · 2020-02-17 18:11:02

For SpaceNut re #170

You're on a roll here (pun intended) !!!

3. manufacture spools of threads that are lobbed once anchored to the surface to travel around the asteriod meant to unspool as it goes around as thrown from the surface.
I like it! Some attention to planning the trajectory for the unwinding is needed! The concept would GREATLY accelerate the delivery of thread to the "carcass".
Furthermore, the container from which the thread is unspooled can itself contain electronics and a low intensity thrust mechanism to slight influence the trajectory. And! The container itself can become a permanent part of the wrapping, by grabbing onto thread already laid to insure it does not bounce off (a) and (b) to increase the strength of the wrapping.
I'm looking forward to seeing how Calliban may evaluate your three suggestions.
(th)

SpaceNut · 2020-02-17 19:59:35

Just think what I could do with toilet paper made from Bamboo and eggs, oh wait no eggs...yet

tahanson43206 · 2020-02-18 10:56:28

For SpaceNut re #170 (with a nod to #172)

After thinking about Option #3 for a while, I'm increasing my assessment of its viability.

That said, the unreeling component of the "toilet roll" needs some intelligence. Specifically, it needs situational awareness AND the ability to control the rate of delivery of thread. The delivery head needs to stay at an elevation decided upon by the engineering team. I'm not sure what that is. It might depend upon the size of the asteroid to be wrapped. It might depend upon the azimuth of the wrapping for an individual delivery head. The delivery head might even need to be able to coordinate with a master control computer on the Asteroid as well as with all the other delivery heads that are swarming around the carcass.

In this scenario, the only variable that the delivery head can control is the rate of spooling of the thread. The delivery head can release less thread per unit of time, and thus increase the speed of rotation of the delivery head about the carcass as the thread is drawn tight and the length of the thread decreases, or the reverse. Meanwhile, the carcass may be moving in a chaotic fashion so that any plans for delivery of the thread are rendered moot, and the control program has to adjust in real time to try to maximize the performance of the swarm and minimize losses due to poorly positioned delivery heads.

Calliban's concept of a rotating thread delivery arm has the distinct advantage of relative stability with respect to the body of the asteroid. It has the distinct disadvantage of slow deployment speed.

An optimum design might feature a hybrid delivery system, with some free flyers as you have proposed, and some fixed position deployment arms. It seems clear (to me as I think about it now) that the two systems should probably not be operated at the same time. The delivery heads can deliver large quantities rapidly but in an uncontrolled way. The fixed base arms can deliver a smaller quantity of material very precisely and very slowly.

Because the flying delivery heads are (potentially) valuable, the fixed base arm might be used to retrieve them, much as the Canadian Arm retrieves a variety of objects on the exterior of the ISS.

In any case, the master control computer needs to maintain a database of deployed thread, so that subsequent launches of delivery heads can be planned to cover gaps in the cocoon.

(th)

tahanson43206 · 2020-02-18 11:02:29

For Calliban re this topic ...

There exists an opportunity for someone to develop a plan for a project to encompass the entire set of activities that would be needed to set equipment on Apophis when it passes through the Earth-Moon plane, and carry out the entire wrapping operation that would lead to a controlled chemical propulsion to capture the object.

Funding would logically follow development of such a plan. Funding is unlikely to precede it, although such unlikely events have occurred in the past in human history when threats loom sufficiently large.

(th)

Calliban · 2020-02-18 16:36:12

Another way of making this work would be to construct a ring around the asteroid and hang the spinning arms from it. The centre of mass of the ring would tend to align with the centre of mass of the asteroid. So the ring could sit stationary whilst the asteroid rotates beneath it. If the two centres of mass come out of alignment, gravity would pull them back into alignment. So the ring would appear to float around the asteroid and would remain stable against mechanical disturbances. The ring could extend wheels down to the surface of the asteroid and use electric motors to change its orientation. If it were to rotate around the poles as the asteroid spins equatorially beneath it, then multiple arms around the circumference of the ring would deploy threads simultaneously and wrap the asteroid in a spiral pattern.

Before wrapping could begin, arms mounted on the ring would collect enough surface rock to create the basalt fibres. When the wrapping operation is completed, the ring could be used to accelerate the asteroid, by accelerating excavated material from the asteroid in the opposite direction to rotation. In fact, it would be possible to propel mined material back to Earth by accelerating packages from a long tether attached to the ring and released at the right moment. The ring itself would be powered by solar energy, provided by solar panels mounted around its rim.

Last edited by Calliban (2020-02-18 16:42:18)

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