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#176 2020-02-18 18:33:29

SpaceNut
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Re: Colonizing / terraforming small asteroids

The moment mass is added to the ring the direction will be to cause the ring to move towards the asteriod. That mass is the spools of fiber. There needs to be a means to keep it stationary... so the arm wheels to the surface would work if there are multiple places that they are mounted to the ring to stabilize the mass shifting that would occur as the web is wound around the asteriod.

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#177 2020-02-20 11:17:40

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re topic ...

It is time to bring your asteroid topic back into view.

The article at the link below describes work (apparently) done at MIT to focus on Apophis:

https://www.yahoo.com/news/mit-system-p … 27807.html

The cocoon idea has not yet migrated out of this little forum, but it could hitch a ride on an initiative from MIT.

The researcher quoted is at least thinking about sending probes to the asteroid.  That is a useful first step, and it should be encouraged, in my opinion.

However, the ** big ** interest is likely to come from the idea of harvesting the asteroid, instead of just deflecting it.

(th)

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#178 2020-02-22 07:31:31

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re topic ....

A pathway for development of this topic, and particularly for development of the cocoon concept for preparing Apophis for navigation to a new location for harvesting, is to bring new contributors with relevant education and experience into the discussion.

Yesterday, in a social setting, I was able to renew an invitation to take a look at this topic.  There are at least two PhD level contributors to this forum, and there are quite likely to be more.  At the same time, there are contributors with lifetime experience in technical fields of various kinds.

I'd like to see the cocoon idea develop into a project proposal of sufficient quality to enter competition for funding by major government agencies or major private organizations.

We have a firm timeline of 2029 available to help with focus.  Apophis will pass through the solar plane inside the Geosynchronous orbit of Earth, and while some clever space navigation will be required to land probes of various kinds on the object, there is plenty of time for this group on NewMars forum to lead in an effort to create a viable plan and to support initiatives to create hardware to follow through.

(th)

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#179 2020-02-22 11:17:39

SpaceNut
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Re: Colonizing / terraforming small asteroids

The target once we know its orbital path dictates that mission timing but what it can not control is the funding for the mission, launcher,
payload mass to accomplish task and time to finish before we cross that domesday line along the path towards earth.

https://www.nasa.gov/home/hqnews/2009/o … pdate.html

"Apophis has been one of those celestial bodies that has captured the public's interest since it was discovered in 2004," said Chesley. "Updated computational techniques and newly available data indicate the probability of an Earth encounter on April 13, 2036, for Apophis has dropped from one-in-45,000 to about four-in-a million."

The information provided a more accurate glimpse of Apophis' orbit well into the latter part of this century. Among the findings is another close encounter by the asteroid with Earth in 2068 with chance of impact currently at approximately three-in-a-million. As with earlier orbital estimates where Earth impacts in 2029 and 2036 could not initially be ruled out due to the need for additional data, it is expected that the 2068 encounter will diminish in probability as more information about Apophis is acquired.

Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteriod ruled out any possibility of an impact in 2029. However, the asteroid is expected to make a record-setting -- but harmless -- close approach to Earth on Friday, April 13, 2029, when it comes no closer than 18,300 miles above Earth's surface.

For a bit of context, the Moon is somewhere between 225,000 and 252,000 miles away at any given time, With a close encounter to occur  on April 13th, 2029, the asteroid known as Apophis will pass by Earth at a distance of just 19,000 miles.
At present, it doesn’t appear as though the rock will pose a threat during its flybys after 2060, but astronomers can’t completely rule it out.

This image describes why we are wanting to cacoon the asteriods
asteroid.jpg?quality=98&strip=all&w=782

Something to keep in mind is the design for the equipment is usually a period from 4-6 years for verified hardware and firmware to be able to launch for use..sure 10 years to it being here sounds like a long time to prepare but the reality is that we may not make it.

https://www.space.com/asteroid-apophis- … fense.html

A depiction of the location of earth satelites to the asteriod crossing
cZX7dPNYGvaNUjPqdeBNxF-650-80.gif

The effects of earth gravity on a rock pile is the question for the crossing.

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#180 2020-02-22 18:36:50

SpaceNut
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Re: Colonizing / terraforming small asteroids

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#181 2020-02-22 19:32:22

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut re #179 and #180

Thanks for your interesting and helpful additions to the topic!

The image you found for the asteroid has some intriguing qualities.  I'm presuming this is artwork, and inspired if true.

(th)

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#182 2020-02-23 10:48:39

SpaceNut
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Re: Colonizing / terraforming small asteroids

Edit

tahanson43206 wrote:

For SpaceNut re #

First, thanks for the reminder of the many contributions of JoshNH4H during his tenure as a moderator and member of the forum.

And thanks for the interesting teaser of an opportunity for the Asteroid Cocoon contingent. 

From my perspective, some work is still needed to reduce uncertainty in numerous areas. 

I'm not sure how many bullet points I'm going to come up with, but I'll start and see how far it goes ...

1) Is the surface of Apophis suitable for manufacture into thread?

2) Can equipment fabricated for manufacture of basalt thread here on Earth be adapted to deep space and whatever material Apophis offers?

3) Is there an optimum strategy for wrapping the cocoon.  Calliban's long arm from a pole is what Nature offers as a model, but that would be slowest.

4) Would SpaceNut's idea of tossed toilet paper rolls (as a metaphor of course) work at all, and if so, how would it be designed for the free space situation?

5) What amount of wrapping material is needed?  Nature provides a model of multiple layers of thread. Can we get by with less?

6) Where would the world want the asteroid to be delivered?  I say the world, because there is ** no ** doubt the world has an interest in the project.

7) Speaking of the world ... what international agreements are needed to avoid unhappy and worried people, let alone nations?

Enough for now ...

(th)

Maybe its time for a consolidated write up for this topic to be posted on the home page..targetting the above bullets to finish out what we might be missing...

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#183 2020-02-23 15:03:09

Calliban
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Re: Colonizing / terraforming small asteroids

I believe that Spacenut's idea of rolls of basalt fibre deployed by a walking vehicle is probably the most practicable.  Attached is a link to an article showing an image of a filament wound pressure vessel.  Note that the windings are helical and circumferential.
https://www.compositesworld.com/article … re-vessels

Last edited by Calliban (2020-02-23 15:20:41)


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#184 2020-02-23 15:11:53

SpaceNut
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Re: Colonizing / terraforming small asteroids

That just means we have two viable concepts for getting it done.

off site link https://luf.org/2020/02/23/cocoon-for-apophis/

The spool is anchored to the thread and the end of the thread is anchored to the surface once loaded on the catapult for launch the vehicles that load it and even the catapult as then moved so that the free toss is able to wrap until it unspools all the way to its end. The weight of the spool will allow for the momentum to be sustained throughout the spin around the asteriod. A counter rolling mass on the inside of the spool will keey it paying out the thread as it travels around the asteriod. That weight starts to roll on the first tension hit it takes from the spool drawing taunt and rolling or you can add an electrical device to give it a shove to start the counter roll feature used to stabilize the rolling of the spool. The natural asteriod spin will aid in that circling of the wrapping until; its all off and then its will be drawn to the surface so that a robotic unit can go and anchor the end and bring the spool back to the thread factory.

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#185 2020-02-23 17:41:47

Calliban
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Re: Colonizing / terraforming small asteroids

In terms of required thickness: the example from the Composite World website for the satellite propellant tank, suggests that operating pressure should be about one tenth bursting pressure.  Taking tensile strength to be 3GPa, operating stress should be no more than 300MPa.  Presumably, this accounts for some anticipated damage from micro meteorites.

Apophis is 450m long and 170m in diameter.  Using the thin walled pressure vessel equation for a shell pressure of 100KPa and working stress of 300MPa, gives a shell thickness of 2.8cm.  If the ribbon is 1mm thick, say, it would need to be enrolled around the asteroid some 28 times.  The total mass of the basalt ribbon is approximately 90,000 tonnes.  Total volume of material is 34,000m3.


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#186 2020-02-23 18:55:33

SpaceNut
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Re: Colonizing / terraforming small asteroids

That said we need to mine and process that plus for waste, how much in depth from the crust of the asteriod to get that much volume to be able to wrap the asteriod.. so at least 5 cm seems reasonable but most likely more as its got to be pretty much the same chemistry to make it work..

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#187 2020-02-23 19:04:53

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re #185 ...

Thank you for adding the mass and length (approximate) of the basalt thread.  A question still open is whether the material comprising the outer layer of the asteroid can be processed to deliver a suitable thread.  Earlier, you cautioned that some carbon based material is needed to protect the basalt from fractures which are sure to occur during manipulation of the thread.  That material may need to be brought along by the wrapping "committee".

I'd like to mention that if I recall correctly, elderflower worked in the chemical field for many years, and (again depending upon memory) designed at least one large scale manufacturing facility.  Making thread for this operation in situ will be a challenge in the field of chemical engineering.

A few messages back, elderflower provided support for the natural example of a spider wrapping its victim.  I've been thinking about how that might be realized in a microgravity environment, since "walking" is probably not possible.  However, a spider ** could ** operate nicely by working ** under ** a thread already laid. A thread would have to be laid by SpaceNut's thrown toilet paper roll example.  However, once the flying reel is retrieved back at the starting point, it can be secured to the spider, and at that point, the spider can use the first thread as an inverse balance wire.  It would be terrific if someone in the NewMars community could draw images of what that would look like.  Multiple spiders could be operating at once, since they would all be operating under computer control from a master computer in the thread manufacturing component.

(th)

Last edited by tahanson43206 (2020-02-23 20:24:00)

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#188 2020-02-23 19:49:24

SpaceNut
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Re: Colonizing / terraforming small asteroids

post 149 has the antartica walking building to contain the processing plant.

Sure a guide for the walking spider could help to keep it in place while its mining to process and crunching up the materials making it acceptible for the process to work on it.

The threads could also be woven into a given width across and thickness before wrapping it on the spool so as to limit the tossing of the spool most likely made of metals brought with us. One could leave a loop on the woven pieces to run a thread through to stitch the sections together.

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#189 2020-02-28 08:58:24

Calliban
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Re: Colonizing / terraforming small asteroids

Interesting story.
https://www.space.com/minimoon-2020-cd3 … ained.html

I wonder if there are any asteroids in the 30-100m size range, whose orbits are close enough to Earth, in terms of apogee and perigee, that we could nudge them into a semi-stable high Earth orbit using electromagnetic propulsion of some kind?  The propulsive adjustment could be carried out by a robotic spacecraft.

A mission to a captured body would be much easier, as the vehicle would take only a week to reach it and then another week to get home.  So the habitation requirements of the vehicle are far more relaxed.  It would also be much more economical, as a single reusable vehicle could make multiple round trips between the body and LEO over the course of a single year, using the asteroids own surface material as reaction mass.  A much more practical approach to asteroid mining.


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#190 2020-02-28 18:01:42

SpaceNut
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Re: Colonizing / terraforming small asteroids

A little moon or large boulder was just captured but is not for long to stay with the earth as it orbits it for now soon to depart in April.

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#191 2020-02-28 18:08:23

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban ... the story at the link below seems right for the topic:

https://techcrunch.com/2020/02/28/space … -asteroid/

The asteroid is between Mars and Jupiter.

(th)

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#192 2020-02-29 08:46:28

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re topic ...

Thank you again for your generosity in releasing "Calliban's Spider" for public use.  I received a reply from a large organization of science fiction writers, indicating they will give the term exposure.  Initial exposure will be to a small group of decision makers.

Please consider developing ideas for wrapping Apophis in basalt thread in the weeks ahead.   The earliest that a science fiction story could appear is about a year from now, for a variety of reasons.  During that time, there will be ample time for contributors to this topic to add suggestions for real world solutions to the many challenges already identified and yet to be recognized.

As a variation on SpaceNut's toilet paper roll idea, I'd like to build on that with an experience from real life, and hope that other forum contributors will add anecdotes from their experiences or observations.

Warning of Imminent Arrival of Incoming Object:  "Alley Oop"

Many years ago, I attended one of the last one room school houses that existed in the state of residence (in the US).  At recess, a popular activity for the 8 students who ranged from 1st grade to 8th grade was to toss an object over a shed.  As the object was launched over the shed roof, the sender called out "Alley Oop".  I have no idea where the term came from, except that there might have been a connection to a newspaper comic strip popular at the time.

In any case, the connection to the cocoon problem is that a robot could rapidly deploy a single thread around the body of an asteroid by launching an intelligent object to pull the thread from a spool.  The flight object would pull on the thread until the supply was exhausted, and then alter course from free flight to flight constrained by the thread, which would cause the flight object to curve around the asteroid and return to the sender.

Upon return to the sender, the flight object would participate in securing the ends of the thread.  The detail of how that would be done with basalt thread remains to be defined, so I hope to inspire forum contributors to solve the mechanics of that detail to benefit the anticipated author.

There are members of the forum who have demonstrated the kind of imagination and writing ability that could lead to successful publication. 

SearchTerm:AlleyOop

Edit#1: Pulling a thread from a spool has an historic precedent.  Recently a publication included a reprise of the book "Moby Dick" by Herman Melville.  While the book itself was about far more than whaling by people of the 18th Century in the United States, it included details about the whaling industry. Among those details (and a crucial plot element) was the practice of carefully coiling harpoon line in a tub, so that the line could be delivered rapidly, both during the launch of the harpoon, and the flight of the impaled whale.

It is that example from history I was thinking of in writing the "Alley Oop" scenario above.  The tub of thread would be precisely loaded by the thread manufacturing system so that the flight of the intelligent object would be impeded as little as possible on its journey away from the launch point.

(th)

Last edited by tahanson43206 (2020-02-29 08:53:58)

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#193 2020-03-01 09:39:55

Calliban
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Re: Colonizing / terraforming small asteroids

If the fibres were equipped with a conducting core, then a wheeled vehicle laying the cable could be held against the asteroid using magnetic forces.  It would carry an electromagnetic that would pull it towards the current carrying cable with enough force to allow wheels to generate traction.  There are a few ways this could work.  We could cover the asteroid in a thin ferromagnetic net before we start laying the basalt fibre.  The electromagnet on the vehicle would would pull on the net, which would exert an equal and opposite pull on the electromagnet, rather like artificial gravity.  The basalt fibres would then be laid on top of the net.  Or we could make all of the basalt fibres electrically conducting and lay a guide loop to start the process off, with each subsequent loop being energised from a power supply on the vehicle itself.  Another option would be to drill into the asteroid and deposit a superconducting magnet close to its core.  Anything made from steel on the surface of the asteroid would be pulled to it in a way not unlike gravity on a larger body.  So a wheeled vehicle made from steel should be able to provide traction.  The final idea is more of a stretch I think, as the magnetic field would need to penetrate up to 200m of intervening rock.

Last edited by Calliban (2020-03-01 09:42:49)


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#194 2020-03-01 11:00:20

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re #193

Your suggestion of placing a magnet at the center of the asteroid to facilitate "artificial gravity" is quite interesting.

As so often happens it is embarrassing, I had not thought of it before << sign >>

However, when I went to Google to confirm my recollection that field strength falls off as the square of the distance, I ran into something I did NOT anticipate:

Magnetic Fields Varying as an Inverse Cube
For both monopoles and dipoles, the field strength decreases as the distance from the source increases. , often called the inverse square law. For electric dipoles, the field strength decreases more rapidly with distance; as R -3 .

Magnetic Dipole Field Strength - Millersville University

I was aware that the field strength of poles in opposition falls off as the cube of the distance, because I've looked into the physics of magnetic repulsion (a little bit). What caught me by surprise was the "news to me" that the exact same limitation must apply to the attractive pole.  It would certainly make sense! After all, Nature likes symmetry.  Still, what it means is that the best pulling effect for your proposal would be to orient the magnet at the center of the asteroid so that the thread delivery agent is away from the poles.  This could be best achieved if the magnet inside the asteroid could be rotated in place to best serve the thread delivery equipment.

Extending the thought a bit ... a tunnel excavated from the center of the asteroid would not only provide a passage for the magnet.  It would provide material for the thread manufacturing system.

The mathematics of the magnetic "artificial gravity" should allow for reasonable estimates of field strength needed for a given radius of the asteroid, and a given amount of soft iron on the thread delivery mechanism.

The strength of the field could be increased by adding to the current flowing in the coils.

Altogether, I think this latest Calliban contribution is worth developing, and I hope that (at some point) we see others taking an interest in the unfolding of this topic. 

(th)

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#195 2020-03-01 15:40:50

SpaceNut
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Re: Colonizing / terraforming small asteroids

I think the thought was more of how to guide the flying drum along a path as to stepped the drum around the asteriod in order to have the path of the drum able to change course as a function of the field being paced under it and not so much to make gravity or a megasphere field. As with any field intensity, direction or stepping and polarity can be used to our atvantage to make the thread or carpet land where we want it to as it unspools.

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#196 2020-03-01 18:19:38

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut re #195

it's easy to miss things.  I'd like to point out the passage from Calliban:

Another option would be to drill into the asteroid and deposit a superconducting magnet close to its core.  Anything made from steel on the surface of the asteroid would be pulled to it in a way not unlike gravity on a larger body.

It was that passage to which I was replying in #194

The first part of the post from Calliban did indeed consider a cable laid on the surface.

The alternative, of placing the magnet inside the asteroid, totally eliminates all the tangles that are sure to occur if a cable is laid for the thread deployment robot to follow.

There will be no handy untangler available on the asteroid, so trying to avoid tangles is probably a good idea.

(th)

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#197 2020-03-01 18:45:38

SpaceNut
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Re: Colonizing / terraforming small asteroids

option 2 for allowing a vehicle to move on the surface to deploy the thread without throwing it from the vehicle is to allow for the driving to have a pull on it towards the surface to allow wheel traction to become possible from a magnetic field in the center of the asteriod that we have not dug into yet as we are trying to wrap the asteriod to keep it from falling apart as it is mined.
So we will need to be able to bore into the asteriod to start to tell if we can process the ore for making basalt thread while ever mindfull to not cause it to break apart..
I have suggested to wrap a steel cable around the asteriod before for the machine to use for the anchor to be able to move around it as we place the thread around it in the past while digging just enough material so as to product the weave of thread for deployment onto the surface trailing from behind it as it moves ahead along the cable.

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#198 2020-03-01 19:53:19

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut re #197

Thanks for adding detail about your anchor suggestion.  It is good to have a wide variety of ideas for decision makers to consider.  In the end, I would expect the committee that tries to find the optimum path forward will try to make the most of every unit of currency their backers provide.  Your cable suggestion definitely should be in the mix.  The cable need not be massive, but it will have to be transported from Earth, so if it passes the numerous project reviews, it will have proven its worth to the satisfaction of the committee. 

For Calliban ... SpaceNut brought up an interesting question in #197 .... is it feasible to dig a hole through the center of the asteroid to hold the magnet? 

I suppose the answer would depend in part on the nature of the asteroid.  A metallic asteroid, such as the one NASA has identified as the target of a mission, would resist tunneling, but a rubble pile might not object too much.

99942 Apophis - Wikipedia
en.wikipedia.org › wiki › 99942_Apophis
As of 2014, the diameter of Apophis is estimated to be approximately 370 metres (1,210 ft). Preliminary observations by Goldstone radar in January 2013 effectively ruled out the possibility of an Earth impact by Apophis in 2036.
Average orbital speed: 30.728 km/s
Minor planet category: Aten; NEO, PHA
Named after: Apep
Mean density: ~3.2 g/cm3; 2.6 g/cm3 (assumed)
Torino scale · Gravitational keyhole · Palermo Technical Impact ... · Aten asteroid

If the diameter is 370 meters (that is just an estimate of course) then the radius would be 185 meters.

The strength of a magnet able to provide a force such as one kilogram equivalent, upon a metal plate on meter in diameter, should be knowable.

While looking for a calculator to estimate magnetic force on a plate at a distance of 185 meters from the magnet, I found a (much more practical) web site calculator that appears to be useful for design of machines that use magnets.

https://www.kjmagnetics.com/gap.calculator.asp

Calculating the strength of a magnet capable of exerting a kilogram equivalent of force on a 1 square meter iron plate at a distance of 185 meters may require custom procedures. 

A thread dispensing robot that would "walk" on the surface of an asteroid would necessary dispense the thread slowly.

Nevertheless, such a robot might win the competition for funding because its behavior could be anticipated with greater confidence than the free-flying competitor.

(th)

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#199 2020-03-09 20:09:50

SpaceNut
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Re: Colonizing / terraforming small asteroids

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#200 2020-03-09 20:53:45

tahanson43206
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Re: Colonizing / terraforming small asteroids

for SpaceNut re #199

by Staff Writers
Moscow (Sputnik) Mar 10, 2020

Above the article is an ad for Mars 2020 conference in May.

(th)

Last edited by tahanson43206 (2020-03-09 20:58:08)

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