New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: We've recently made changes to our user database and have removed inactive and spam users. If you can not login, please re-register.

#126 2019-11-04 17:01:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Make more glass for the acids seems to be some of the answer. That said processed ore in space will be used in space rather than send it to earth as its got to come up along ways to make it worth buy from the space source.

Offline

#127 2019-11-05 04:05:34

Terraformer
Member
From: Lancashire
Registered: 2007-08-27
Posts: 3,340
Website

Re: Colonizing / terraforming small asteroids

Sending stuff down a gravity well is cheaper than bringing it up out of one. Particularly nickel, which can be formed into inconel heat shields and dropped off in a friendly desert (Australia?).

Doing refining in space doesn't just reduce the mass you're sending planetside, it also lets you benefit from very cheap solar power. I expect nickel to be the first metal mined, but there could be a future for aluminium smelting too.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

Offline

#128 2019-11-05 04:58:17

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 603

Re: Colonizing / terraforming small asteroids

Solar power for asteroid mining and mineral processing would appear to have excellent power-weight ratio, as it can be in sunlight 100% of the time and no storage is needed.  At Earth orbit with 1350W/m2 insolation, a thin film space solar panel weighing 0.1kg/m2 would deliver 2-3kW/kg.

The only downside is that it does limit operations to asteroids that have relatively circular orbits with apogee not too far beyond Earth orbit around the sun.  Many candidate NEOs have highly elliptical orbits that go beyond the orbit of Mars.  But these wouldn't be our first choice anyway, as the dV requirements to match orbit with them from Earth would be much higher.

We could cast nickel into hollow spheres, sputter it with some sort of molten oxide as a re-entry shield, and drop them either onto land or into the ocean.  Ideally, we want the terminal velocity on impact to be low enough that they survive intact.  Aluminium might be a more profitable asset for building space based structures, at least initially.  It takes 20kWh of electric power to produce 1kg of aluminium.  So a 10m2 solar panel, weighing 1kg, could produce about 8766 times its own weight in aluminium over a 10 year lifespan.  Even if we have to transport the solar panel from Earth, that sort of ratio could make space based aluminium production quite profitable.

Last edited by Calliban (2019-11-05 05:13:24)


Interested in space science, engineering and technology.

Offline

#129 2019-11-05 07:38:34

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Or send them to mars to increase the planets mass with materials that we will need

Offline

#130 2019-11-06 10:19:42

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

For Calliban re topic and bags to enclose asteroids

In another topic:

A fishing technique known to and practiced by many, is to let a line into a body of water in such a way as to attract a fish.  Often, in open ocean settings, the fish which accepts the bait or other attractive element is heavier and stronger than the line can hold.  The operator of the fishing equipment allows the line to pay out against resistance, to tire the fish, always taking care to keep the tension on the line well under its maximum strength.
While the engineering challenges are daunting, the same principle could be applied in capturing incoming vessels arriving at Phobos, or with reference to Calliban's topic about asteroids, could be applied to capturing asteroids.
In both cases, whatever differences in momentum and vector exist between a given object and a vessel intending to capture it could be (in principle) managed by appropriate operation of the line management subsystem.

It occurred to me that a strategy for wrapping an interesting asteroid in one of your bags would be (could be) to allow the asteroid to move into a flat surface of material stretched out by four small automated vehicles pulling at the corners.

Depending upon the relative velocity between the object and the net, the net would be pulled smoothly around the exterior of the object, and the corners would be tied together with mechanical devices.

The attachment point, like the attachment point for deep see fishing with nets, would/could then be used to pull the object if that is desired.

This technique could also work for objects which threaten to collide with Earth.  The bag enclosure you have proposed would solve the problem of loose rubble objects scattering when manipulated.

(th)

Offline

#131 2019-11-09 12:24:59

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Found that we have another topic for lauch in NASA rocket simulator: how to build a rocket

Offline

#132 2019-12-23 20:57:56

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

While following links provided by SpaceNut in another topic, I ran across this paper by students working on the problem of landing on small bodies.

https://arc.aiaa.org/doi/10.2514/6.2018-5365

A Bio-inspired Method to Achieve a Soft Landing on an Asteroid

The storage method at the site seems to prevent extracting text after the title, but the paper should be readily available to anyone following the link.

(th)

Offline

#133 2019-12-23 22:06:07

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Need to be a member of the AIAA to be able to access beyond the first page but in that page it indicates the probes that have already achieved the landing on asteriods and some have been able to bring back samples. We have also lost at least one as it landing was in a shadow such that the solar power would not work.

Offline

#134 2020-01-02 20:39:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Found the Basalt fiber topic

Of course we will need to answer the question for man free suit use Optimal air pressures.. - Which is best? More O2 or more pressure?

Offline

#135 2020-01-03 19:55:24

knightdepaix
Member
Registered: 2014-07-07
Posts: 236

Re: Colonizing / terraforming small asteroids

Shall we just send Near Earth and Mars objects minus Phobos and Deimos to Mars for strip mining?

Offline

#136 2020-01-24 16:19:52

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 603

Re: Colonizing / terraforming small asteroids

SpaceNut wrote:

Found the Basalt fiber topic

Of course we will need to answer the question for man free suit use Optimal air pressures.. - Which is best? More O2 or more pressure?

One way of keeping pressure down, whilst keeping fire risk in check; would be to use a much heavier gas than nitrogen as a buffer.  Flourocarbons are flammable in pure oxygen, but in nitrogen/oxygen mixtures they are non flammable.

Last edited by Calliban (2020-01-24 16:21:32)


Interested in space science, engineering and technology.

Offline

#137 2020-01-24 17:06:05

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Its also about what pressure for that mix which is the issue for any place that we go as we will be starting with near nothing for pressure and little to no oxygen to make what man requires from insitu materials. Less pressure means less energy needed to make the chamber sealed and less energy to make it breathable. It also means less energy to keep it capable of supporting man. Depending on how much volume we need we may be able to bring some of what we need if we have the available payload mass to bring it with the crew when they go.

Offline

#138 2020-01-26 12:20:49

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 603

Re: Colonizing / terraforming small asteroids

This is interesting.
https://caseyhandmer.wordpress.com/2019 … -big-deal/

Given that launch costs have always been so high, there is a tendency to think small.  Musk is now planning for Starships with payload capacity 150te to LEO; 1-day turnaround times and marginal launch costs as low as $35/kg.

This changes quite a bit the plausible mission architectures for this particular thread.  Initially, I predicted that a 100m diameter asteroid would need a 100te vectran restraining bag or net to allow pressurised tunnels to be dug.  If Musk's Starships can deliver to those asteroids for $500/kg or less, then I see no reason why we cannot consider much larger targets.

Given that a certain base-level of capital equipment is needed to allow tunnelling, ore processing, etc, it may make sense to consider larger targets where investment can be concentrated and additions that allow greater self-sufficiency are possible.

A 300m diameter asteroid would require a 2700te vectran restraining bag.  At a delivery cost of $500,000/tonne, the cost of delivering the bag would be $1.35bn.

Last edited by Calliban (2020-01-26 12:29:10)


Interested in space science, engineering and technology.

Offline

#139 2020-01-26 16:44:01

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

The starships moving targets payload to orbit has to due with a ship that has not been built to know the mass fraction, engine performance that is only partically tested, changes now a dual inner tank fuel using all of its fuel to get all the payload to orbit and being empty unable to do anything until refueled. It takes 6 to 7 starship fuel payloads to get it topped off to be able to even move from LEO.
Musk has only an estimate for what his ship will charge let alone how much it will take to make the real deal to launch.

Offline

#140 2020-02-07 05:00:27

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 603

Re: Colonizing / terraforming small asteroids

I did a little research into basalt fibre technology.  This is a key technology for the 'asteroid wrapping' topic, because it would allow ISRU and avoid the need to lift polymer-based nettings from Earth.  Basalt fibres would be enormously useful everywhere as a low-energy alternative to steel in tensile structures, especially pressure shells.  So a key enabling technology for space colonisation is being able to take raw basalt from other solar system bodies and melt it into high tensile material without the need for chemical change.  But there are significant barriers to achieving this on a large scale.

Whilst the raw materials are abundant, to produce a fibre of consistent and predictable mechanical properties, the ratio of iron, magnesium and silicon oxides must fall within a specific range.

The manufacture of basalt fibres is surprisingly expensive.  The material forms a melt at about 1600C and must be drawn through bushings (dies) to produce a fibre ~10microns in diameter.  Because of the temperatures involved and the acidity of the melt, bushings must be made from platinum rhodium alloy.  Not a cheap thing to make.

The process of melting consumes about 5kWh (18MJ) of electricity per kg of basalt melt.   That is about 2/3rd of the equivalent energy needed to make steel.  Given that basalt fibres are about 5 times stronger than steel and have only a third of the density; it takes only 1/20th the energy to produce tensile elements from basalt fibres compared to steel.

For basalt fibre to become a truly cheap material that can challenge steel as a bulk structural component; it will need to be manufactured without the use of platinum-rhodium bushings.  This means finding an alternative bushing material that is much cheaper.  Some type of sintered, high temperature ceramic perhaps?

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

Or maybe a different manufacturing process altogether.  In a zero-g vacuum, maybe we can vaporise the basalt using a laser and allow vapours to condense onto some form of pre-existing fibre substrate?

Some links for further reading.
http://basalt.tech/
www.technology.matthey.com%2Fpdf%2Fpmr-v21-i1-018-024.pdf
https://www.compositesworld.com/blog/po … composites

Last edited by Calliban (2020-02-07 05:15:07)


Interested in space science, engineering and technology.

Offline

#141 2020-02-07 13:52:03

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

For Calliban re #140

Thank you for this update on basalt, and for your research.

I'm curious to know if the product drawn through the die is spooled onto a takeup reel, like thread might be?

My reason for asking is an attempt to understand if mass production requires multiple threads drawn simultaneously or if a single thread can be drawn and spooled for later weaving with other thread.

(th)

Offline

#142 2020-02-07 17:36:23

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Have reposted Calliban's content to the basalt topic.

Offline

#143 2020-02-07 20:48:42

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

Not moved...Calliban is in a different time zone....

https://www.basaltft.com/hist.htm

Basalt fiber is a material made from extremely fine fibers of basalt, which is composed of the minerals plagioclase, pyroxene, and olivine. It is similar to fiberglass, having better physicomechanical properties than fiberglass, but being significantly cheaper than carbon fiber.

3.jpg

Well for the thread going through the die one would not just let it fall to the floor... it is put onto spools and multiple spools would be set up to do a weave in a loom. A fabric is something that is woven from the multiple threads....What make the materials do what we want to for a bagging or for a blanket is the reson that sets up the material just like fiberglass for fixing a boat or a car.....

Basalt Fibers: Alternative to Glass?

https://www.build-on-prince.com/basalt-fiber.html

Offline

#144 2020-02-08 04:19:27

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 603

Re: Colonizing / terraforming small asteroids

Spacenut, the excellent link that you provided, answers some of the unresolved questions I had around bushings.

https://www.compositesworld.com/article … e-to-glass

'Like glass filaments, basalt filaments are formed by platinum-rhodium bushings. As they cool, a sizing agent is applied and the filaments are moved to speed-controlled fiber stretching equipment and then on winding equipment, where the fiber is spooled.

Because the basalt filament is more abrasive than glass, the expensive bushings once needed more frequent refurbishing. As bushings wear, their cylindrical holes wear unevenly, degrading process control. Without timely maintenance, the out-of-round apertures form filaments with an unacceptably wide diameter range, producing a roving with unpredictable breaking loads, explains Nolf. While glass fiber bushings last six months or more before they need to be melted, reformed and redrilled, a bushing used for basalt fiber production previously lasted anywhere from three to five months. Kamenny Vek, however, reports that process control efforts have extended bushing life to a similar six-month cycle.'

The same type of bushing is used for both basalt and glass fibre production.  But basalt is more abrasive and tends to wear out the bushing more rapidly - about 30% less operational life using basalt.  The article mentions that careful process control has eliminated the difference.

It is also noted that bushings can be melted and re-moulded after they go out of spec.  We would presumably need that facility for any space manufacturing, given the huge volume of fibre that is needed.  Later on in the mining process, large amounts of platinum group metals can presumably be sourced from metallic nickel iron within the target asteroid.  Mars appears to have abundant meteorites on its surface that could provide a source of these metals.

It is also noted that fibres need to be coated with a silane based compound to prevent stress fractures when they interact with other surfaces.  This is something that would presumably need to be manufactured insitu.  The hydrogen may need to be sourced from Earth on the asteroid mission, but is abundant on Mars.

The cost of basalt fibre on Earth is $1.25-$5/lbs, about $7/kg on average.  Producing enough of it to wrap a 500m diameter asteroid (about 100,000 tonnes) would cost a 700million dollars, at Earth prices.  Obviously a lot more in space, due to the cost of lifting the factory to LEO, transferring it to the NEO and then deploying the basalt fibre.  But the costs involved do not appear to be infeasible.

Last edited by Calliban (2020-02-08 04:51:59)


Interested in space science, engineering and technology.

Offline

#145 2020-02-08 08:19:08

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

For Calliban re #144 and topic

Thanks to SpaceNut for links to articles showing that basalt filaments are indeed extruded from the melt chamber and wound onto spools.

I'd like to offer a thought that might reduce the complexity of the wrapping process you've been describing for asteroids.

Nature provides the example of a cocoon.

A single basalt melt and extrude machine (robot) could wrap an asteroid of interest in a layer of thread, given sufficient time and solar power if available or nuclear power otherwise.  Once the object is wrapped to a sufficient degree (to be determined in practice) it can be accelerated as a unit towards a location where further processing can be done more effectively and efficiently.

If sufficient resources are available, more than one cocoon spinning robot could be deployed, which would reduce the time required.

The spun cocoon material could (presumably) be unwound at the destination processing facility and saved for other purposes.

(th)

Offline

#146 2020-02-08 13:41:40

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

That would make the ore processing and filament making in orbit around the asteriod. It would be in orbit by momentum but would slow as it has the filament pulled tight around the asteriod as spin of the asteriod and motion of spilling the filament would be oposite to it. You would need to be able to make it at a faster rate than the orbital payout of it to its surface in order to not have a drag but its can not be excessive then its not going to wrap arount it very tightly as we require to hold things in place. Adding to that complexity would be a woven cloth creation as that needs to be at a non intersecting location for the orbital making unit. Both units will need some sort of delivery systenm to get the powered ore to the maker orbital machines. These would need nuclear power sources as solar would add to the complexity.

We would be better off with an on the surface manufacturing of blanket rather than in orbit as we do not have fuels to bring the ore to orbits. Also if its tethered we would then need to keep moving the connecting location. The walking plant also has a simular problem of anchoring and movement as we string or weave the filament around the asteriod.

Offline

#147 2020-02-08 14:24:47

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 20,275

Re: Colonizing / terraforming small asteroids

You know just a single word can trigger a memory and I seem to recall a mobile habitat thaty walks on earth and its in use already in Antartica.
Lets alter its use but make use of its size to assist in making a mobile self contained mining to end woven plant for use on Mars or the asteriods keeping in mind that we need to be able to land the mass for mars as it will be by and far easier on the asteriod. As indicated before self automated with telerobotic control supplied by nuclear power in the 10 kw where we obsorb the radiated enegey for other pocesses in the mining processing area of the units design.
If the mass needs to be distributed to several modules we can link them together to form a train like movement.
antarctica_03.jpg

This will be part of the Mars My Hacienda topic plot concepts of roving and mining business concepts as part of the Teohold plot 0003 post #19. It is also part of the mobile roving plot 0008 registry as well to process materials to make temporary habitats for each plot to make use of. The habitats might be able to make use of a 3D weaving process which is being used on the Adept heatshield. We will need to see where it fits into the other open registries as a business and for how many might be needed to make all of the product types from chairs to rebar....

Offline

#148 2020-02-09 12:50:38

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

This is primarily for Calliban, but it may be of interest to others ...

The latest issue of Analog just arrived.  It will be available on newsstands shortly, and is probably available in library subscribers already.

arlan andrews sr
About 81,900 results (0.34 seconds) 

Article: The Pournelle Volume
Analog Science Fact & Science Fiction
March/april 2020 Vol CXXXX Nos. 3 & 4
Named for Dr. jerry Pournelle
Book: A Step Farther Out
Quick and easily understood method of accessing the potential value of an asteroid

Quote from page 37 of Analog article:

1.0 Pournelle Volume (PV) of (mineral, element, compount) = Volume of annual world production of that same resource in a specified reference year. For example, rounding off “Business Insider's” 2013 values.
1.0 PV of gold … 150 cubic meters
1.0 PV of uranium … 3,000 cubic meters
1.0 PV of copper … 2,000,000 cubic meters
1.0 PV of iron … 375,000,000 cubic meters

Quote from notes at bottom of page 37:

This article is an excerpt from a presentation entitled “Repurposing Asteroids”, written by Dr. Arlan Andrews, Sr., Sc.D, P.E., for the Tennessee Valley Interstellar Workshop in Oak Ridge, Tennessee, held in October 2018.  The paper was presented by by Dr. Catherine Asaro

(th)

Last edited by tahanson43206 (2020-02-09 12:51:49)

Offline

#149 2020-02-09 20:22:11

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

For SpaceNut re #146

I've been waiting to see if anyone else might take up your interesting ideas about the spinning of a cocoon around an asteroid to be harvested.

I liked the variety of options you thought of.  The idea of weaving seemed a bit perplexing to me when I first read it, but after a few hours I've been able to imagine a coordinated flight pattern for a swarm of thread extruding robots, designed to criss-cross each other's thread.

Over time, the mesh thus created should be able to create a net similar in function to the one that Calliban was originally describing as shipped from Earth.

I like the general concept for asteroid deflection, which is a potential source of funding for an entrepreneur able to gather the resources to design a set of robots able to enclose an asteroid, so that it can be given a direct thrust, without the risk of all the rubble scattering about.

As a side issue ... There may well turn out to be a benefit to harvesting basalt from a small asteroid with the needed characteristics, to load up the spider robots to be routed over to the ** real ** target asteroid, which would presumably contain desirable materials.  That asteroid could be wrapped up and then given momentum to bring it eventually to a location where it could be economically processed to yield salable commodities.

(th)

Last edited by tahanson43206 (2020-02-09 20:24:02)

Offline

#150 2020-02-10 07:55:08

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 4,160

Re: Colonizing / terraforming small asteroids

As a follow up to #149 ...

SearchTerm:CallibansSpider
SearchTerm:SpiderAsteroidCocoon
SearchTerm:CocoonAsteroidCapture

The owner of the "Calliban" brand on NewMars forum is free to trademark the expression "Calliban's Spider" if there would be a reason to do so.

The asteroid harvesting system designed around "Calliban's Spider" would include (at minimum):

1) Design for a basalt thread extruding machine able to operate in space using solar power for energy and asteroid material for input
2) Design of a basalt thread laying robot (the "spider") able to operate in a swarm configuration with other similar units
3) Design of a strategy for deployment of a swarm of "spider" devices to encapsulate an asteroid with minimal expenditure of material and time
4) Design of a strategy for providing momentum to a captured asteroid to deliver it to a processing location elsewhere in the Solar system
5) Design for prospecting robot devices, able to gather and report information about particular asteroids

(th)

Last edited by tahanson43206 (2020-02-28 21:37:39)

Offline

Board footer

Powered by FluxBB