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#26 2019-08-21 18:07:33

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,706

Re: Colonizing / terraforming small asteroids

Second time to send a post....

I agree with that and notice that its only 380 meter diameter so spin will be very slow of under 2RPM to get earth gravity.

Radiation outer shell kept to a thickness of 10 Meter seems to be plenty.

https://phys.org/news/2018-10-modular-m … lding.html

4-plansforamod.jpg

Use structural ribbing to keep it stable with multiple floors to support internal mass as it grows.

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#27 2019-08-22 04:29:55

tahanson43206
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Registered: 2018-04-27
Posts: 3,527

Re: Colonizing / terraforming small asteroids

For spaceNut re #26

civil engineer Marco Peroni

Thanks for the link to the phys.org paper.  I think there is a good chance some of this gent's ideas will receive funding.

I was surprised to see the prediction that the proposed magnetic shield would be effective against cosmic rays, and would like to see more details of how the shield would be deployed. 

On the other hand, some elements of the designs seem appealing.

(th)

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#28 2019-08-22 04:32:16

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 532

Re: Colonizing / terraforming small asteroids

The design referenced by Spacenut is interesting in its use of magnetic fields to deflect charged radiation, thus avoiding the need for heavy shielding.  However, I note that it consists of 900 modules each weighing 40-50 metric tonnes.  That is a lot of mass if it needs to be launched from Earth.  Maybe there is a way to develop this on a slightly smaller and more incremental scale?

Peroni's estimate of 740mSv per year surface doses on Mars seem rather excessive.  That is representative of cosmic ray doses in interplanetary space.  The data I have seen for mars surface dose rates of about 200mSv/year (20 rems).  But I digress.

I think any real spacecraft that we send to an asteroid will probably be far more weight constrained than this.  If we reach the asteroid relatively quickly, perhaps we could use surface materials for shielding, or set up a magnetic ring that shields the surface?  If we choose Apophis as the baseline for the mission concept, and it takes only a day or two to reach it's surface; is it realistic to assume that the spacecraft itself will not need special shielding for such a short trip?

PS.  I recalculated the amount of basalt fibre needed to reinforce Apophis to allow it to spin up to provide lunar gravity (0.17g) at its far ends (it is an oblique spheroid).  It works out at 46,500 tonnes, assuming a fibre stress of 1GPa.  I also came to the realisation that an asteroid that is reforced in this way may not need any separate provision for pressure containment, because the weight of the rock above will tend to stiffen the walls of the tunnels, so long as they aren't too far from the axis.

Last edited by Calliban (2019-08-22 06:18:16)


Interested in space science, engineering and technology.

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#29 2019-08-22 09:56:00

tahanson43206
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Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban re #28 ...

Would you be willing to revise your "first visit" plan for Apophis so that the actual encounter is performed by a combination of AI and telepresence?  The probe that recently visited Ceres (and another remote object) was able to function without direct human control, although telepresence (with time delay) was used to program the behavior of the systems on the probe.

A (relatively) light weight vehicle could accelerate from GEO (as just one example of an approach) to match orbit with the asteroid as it passes close to the Earth, well inside GEO itself.  However, due to the proximity of Earth, high data rate telepresence would be possible for a short period of time, followed by reducing data rates as the body recedes.

Multiple missions are possible and perhaps even likely, if the idea of landing on the asteroid becomes popular.

***
By any chance, do you have Heppenheimer in your library?  I was reviewing my yellowed copy of the paperback today, while waiting for an appointment, and found on (about) page 135 a detailed discussion of the procedure for smelting lunar rocks in a free flying "construction shack".  I was struck by the similarity of those 1977 musings, and your more recent posting about how materials would be differentiated in space.

Not much has changed over the decades, it would appear.

Edit: In particular, I was struck by Heppenheimer's description of sputtering of aluminum mist onto a fabric balloon, to make the walls of a habitat cylinder.

(th)

Last edited by tahanson43206 (2019-08-22 09:59:05)

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#30 2019-08-22 10:52:03

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 532

Re: Colonizing / terraforming small asteroids

tahanson43206 wrote:

For Calliban re #28 ...

Would you be willing to revise your "first visit" plan for Apophis so that the actual encounter is performed by a combination of AI and telepresence?  The probe that recently visited Ceres (and another remote object) was able to function without direct human control, although telepresence (with time delay) was used to program the behavior of the systems on the probe.

A (relatively) light weight vehicle could accelerate from GEO (as just one example of an approach) to match orbit with the asteroid as it passes close to the Earth, well inside GEO itself.  However, due to the proximity of Earth, high data rate telepresence would be possible for a short period of time, followed by reducing data rates as the body recedes.

Multiple missions are possible and perhaps even likely, if the idea of landing on the asteroid becomes popular.

***
By any chance, do you have Heppenheimer in your library?  I was reviewing my yellowed copy of the paperback today, while waiting for an appointment, and found on (about) page 135 a detailed discussion of the procedure for smelting lunar rocks in a free flying "construction shack".  I was struck by the similarity of those 1977 musings, and your more recent posting about how materials would be differentiated in space.

Not much has changed over the decades, it would appear.

Edit: In particular, I was struck by Heppenheimer's description of sputtering of aluminum mist onto a fabric balloon, to make the walls of a habitat cylinder.

(th)

There are no doubt many possible mission proposals that could yield valuable results.

I do not have Heppenheimer's work, but his proposal for vacuum plating is interesting and similar to a proposal that I can remember reading in Gerard O'Neills 'The High Frontier'.  One possible issue with this idea is the use of aluminium, which takes about 20kWh of power to produce a single kg and takes place in super high temperature electrolysis cells, using carbon electrodes.  I can't see it being an easy thing to make in space.  If the same thing could be done using iron, it would be technically much easier.


Interested in space science, engineering and technology.

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#31 2019-08-22 12:02:09

tahanson43206
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Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban #30 ...

https://www.amazon.com/Colonies-Space-T … way&sr=8-1

A used hardcopy is available.  I recommend it over the small paperback, for greater ease of reading and color illustrations (I think (not certain)).

If you decide to invest in a copy, I'll pull mine out of the archive and have it available to compare notes.

The paperback is going to a freshman headed off to college.  It was published in 1977, but much of the technology seems as fresh as the day it was printed.  The computer capabilities have improved of course, but physics hasn't changed much in that time.

Heppenheimer was part of the Stanford Torus summer study.

(th)

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#32 2019-08-22 17:27:34

SpaceNut
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Re: Colonizing / terraforming small asteroids

While in the construction mode the hollowing out of the planetoid we will need to capture what we do not use in the basalt fiber filaments which would be used for sealing the surface from it moving and leakig the air from inside once we can pressurize it for man. What I am thinking of is using the fibers to make a bagging system to make use of the material excavated as a micro-meteor impact cushion. Attaching the filled bags to a tether line on the surface to goes around interlocking these crossing cables to keep the material where it is put. We can remove bags as needed once we are ready to build with the materials inside.

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#33 2019-08-22 17:53:16

tahanson43206
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Posts: 3,527

Re: Colonizing / terraforming small asteroids

For SpaceNut re #32 ...

Bravo! It seems to me you have combined the bag idea from Calliban with other ideas to create a concept I've not seen before.  It could be that the idea of using bags of material in space to shore up defenses, much as we use sand bags on Earth to try to prevent flooding of selected areas, is already published either in the scientific or fiction literature, but I do not recall seeing it.

I'm hoping Calliban will weigh in on this adaptation of his original idea.  As I recall, Calliban was thinking about an air tight bag, but over the progress of the topic, the bag was seen as a way of capturing loose material from a object, and now (it seems to me) the idea has morphed into a knitted wall of material around the object of interest.

The small bags of material, if "knitted" together, could still provide the capture function.

(th)

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#34 2019-08-22 18:48:28

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,706

Re: Colonizing / terraforming small asteroids

At somepoint when I would say the internal is 80 - 90 % of the planetoid has been removed we will want to switch over to having men there to help in finishing out the internal construction of wiring, plumbing and much more. The bore hole for the initial entrace and exit on the oposite side would need to have a docking means attached for crews to have a mainway to traverse inward and to have an airlock chamber made possible.

This might be how we would want to land internal
homevideo.jpg

With this might be docking external when this is attacked to the planetoid
lmsm_infograph_1.jpg

Notice the last has multiple ports for ships to dock to while the first limits due to size.....

In ether case landing on the bags or sealed blanket would work against all the work after each landing and leaving has occured.

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#35 2019-08-23 05:16:22

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 532

Re: Colonizing / terraforming small asteroids

tahanson43206 wrote:

For Calliban #30 ...

https://www.amazon.com/Colonies-Space-T … way&sr=8-1

A used hardcopy is available.  I recommend it over the small paperback, for greater ease of reading and color illustrations (I think (not certain)).

If you decide to invest in a copy, I'll pull mine out of the archive and have it available to compare notes.

The paperback is going to a freshman headed off to college.  It was published in 1977, but much of the technology seems as fresh as the day it was printed.  The computer capabilities have improved of course, but physics hasn't changed much in that time.

Heppenheimer was part of the Stanford Torus summer study.

(th)

Thanks tahanson, I will buy a copy.  I cannot seem to get a copy of Asteroid Mining 101 for less than $100.  It appears to be out of print, not sure why.


SapceNut wrote:

At somepoint when I would say the internal is 80 - 90 % of the planetoid has been removed we will want to switch over to having men there to help in finishing out the internal construction of wiring, plumbing and much more. The bore hole for the initial entrace and exit on the oposite side would need to have a docking means attached for crews to have a mainway to traverse inward and to have an airlock chamber made possible.

I think the process is likely to be incremental.  We would start with a minimal bag structure to allow the beginning of mining activities.  As time proceeds and mining produces more silicate waste material, we would use it to progressively reinforce the bag and allow the tunnel network to expand and gradually increase spin gravity.  This allows us to do more as we earn more money by selling the mined material.

The destination for any mined material will be Earth orbit.  We will need a certain amount of reaction mass to transport valuable metals from the asteroid to Earth orbit where they can be processed into other valuable products or exported to Earth's surface.  I would imagine that reaction mass will account for a lot of the bulk silicates, though some may remain available for the production of basalt fibres.

It is enormously advantageous for manufacturing operations to take place in Earth orbit.  It requires less delta-v to ship equipment into Earth orbit than it does to ship it to the surface of the asteroid.  Repairs and communication are easier and most important of all, operations in Earth orbit can be teleoperated from Earth, with only a minimal crew needed to address problems if anything malfunctions.  This has the potential to significantly reduce costs and would be cumbersome if attempted at more distant targets.

The idea of using thin bags of loose material to shield against micrometeorites is a good idea.  In the absence of this, the safety factor of the pressure restraining bag has to be over-specified in order to accommodate micrometeorite damage.  It would also likely have only a limited design life.

Last edited by Calliban (2019-08-23 05:23:39)


Interested in space science, engineering and technology.

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#36 2019-08-23 12:16:03

tahanson43206
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Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban re #35 ...

Thanks for deciding to pick up a copy of Colonies in Space.  The small paperback i've been re-reading is on it's way to college, after it's turnover today.  I recognize this is a gamble, because the student's major is NOT related, but the student is about to attend a university where aerospace, science and advanced technology in general are well advanced.  This particular school is not at MIT or Caltech level, but (I'm guessing) a solid member of the second tier.

Thanks for endorsing (albeit provisionally) SpaceNut's suggestion of small bags of regolith to be assembled into shields for humans, as well as storage containers for materials which might have been given preliminary selection, to expedite later processing.

I'm hoping that as we go along, you will be willing to modestly revise the ambitions for the first encounter with Apophis (assuming you decide to continue focus there).  Your presentation still looks (to my eye at least) as though you'd be well past the exploration and discovery phase.

What I'd like to propose for your consideration is a scenario that would unfold in seven year increments, so long as the orbit brings the asteroid near Earth.

The 2029 pass is a perfect opportunity to land all kinds of sensor packages, analysis packages, and even a test material processing package or two, given that the asteroid has not (to my knowledge) been adequately characterized to be able to make reasonable decisions.

However, during the seven years until the asteroid returns, the flood of data (from the various parties) should enable sensible decisions about how to dis-assemble the parts of the asteroid which would have value in Earth orbit, and even as a remote possibility, on Earth if a component is worth the effort.

At that point, the next round of visiting systems should be able to perform all the processing that might be needed to:

a) Recover any materials that might be worthy of extraction to pay the bills
b) Create bags of selected material for use as shield and as input to processing downstream
c) Installation of ion engines to adjust the orbit to insure optimum passes in the future (ie, not too close, and not too far)

***
All this work should be transferable to other objects, as lessons are learned and hopefully shared.

Edit ... I'll look at the "101" problem, but have low expectations of success since you've already looked.

However, there IS a possible (round-about) solution...

In the city where I live, there is a global library resource.  It publishes an online index of books and other materials, and the database includes listings for a number of nations.

If you are not already familiar with it, try worldcat.org, to see if a copy of "101" might be in the collection of a University or other library near you.

Edit(2) ... I decided to order both the Heppenheimer and Lewis' first book.  "101" best offer I found (so far) was $76.00.  Too rich for me << sigh >>

Both books are probably in the boxes from past moves, but it is easier just to order "new" (used) ones.

(th)

Last edited by tahanson43206 (2019-08-23 12:39:22)

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#37 2019-08-23 17:01:19

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,706

Re: Colonizing / terraforming small asteroids

To send missions we need a greater detail of information for launch cycles.
Images of Earth Apophis Orbital Encounters

https://cneos.jpl.nasa.gov/doc/apophis/image3.html

Its orbital path covers a bit inside earth orbit and a bit outside of it as it circles the sun at a period shorter than earths.


Predicting Apophis' Earth Encounters in 2029 and 2036

http://planetary-mechanics.com/2018/07/ … r-apophis/

But Nasa has a plan for a manned visit as a Preliminary Design of a Crewed Mission to Asteroid Apophis ...
http://wordpress.engineering.iastate.ed … 0-8374.pdf

Constellation hardware for a crewed NEO mission for a 45-180 day mission with a 7-14 day asteroid stay time

Thats a flag and foot print mission for the surface of the asteriod... we need tons more supplies than that and AG radiation protection from the start or this mission will be robotic....

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#38 2019-08-23 17:30:55

tahanson43206
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Registered: 2018-04-27
Posts: 3,527

Re: Colonizing / terraforming small asteroids

For SpaceNut re #37 ....  First, thanks for the multiple links covering Apophis orbits and predicted encounters.

Second, just FYI ... the wordpress link did not come up for me, but it appears to have come up for you.

I got:

wordpress.engineering.iastate.edu’s server IP address could not be found.

(th)

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#39 2019-08-23 19:39:36

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,706

Re: Colonizing / terraforming small asteroids

I did a couple of checks for the browser and address and it works in opera 12 but not Ie8 or firefox 48.0.2

Preliminary Design of a Crewed Mission to Asteroid Apophis in 2029-2036
It can be found here as well https://arc.aiaa.org/doi/abs/10.2514/6.2010-8374


Here is another which is newer
https://ntrs.nasa.gov/archive/nasa/casi … 017159.pdf
A Crewed Mission to Apophis Using a Hybrid Bimodal Nuclear Thermal Electric Propulsion (BNTEP) System

At one point Nasa wanted to deflect an asteriod
https://kundoc.com/pdf-robotic-and-huma … apoph.html

Automated trajectory design for impulsive and low thrust interplanetary mission analysis
https://core.ac.uk/download/pdf/38931363.pdf

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#40 2019-08-23 21:19:36

tahanson43206
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Posts: 3,527

Re: Colonizing / terraforming small asteroids

For SpaceNut re #39 ... Bingo!  Thanks for finding the nature of the problem (a) and (b) providing the newer link at ... 017159.pdf.

It came up fine on Linux/Chrome (from before it transitioned to Chromium) and I'm looking forward to reading it carefully tomorrow.

The pdf has a date of 2010, which is recent enough I'm expecting a study which would be pertinent today.

The search for a suitable target for a Manned Mission makes sense for the NASA team working on SLS.  The SLS should fly in the next few years, if funding does not go away due to competition from the private sector.

I still think robotic missions with telepresence makes a lot of sense, so hopefully others than NASA will think along those lines.

(th)

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#41 2019-08-24 06:54:22

tahanson43206
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Registered: 2018-04-27
Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban re topic ...

Your decision to invest in a copy of Heppenheimer inspired me to do the same, and to raise by ordering the early Lewis.

Your decision to venture into this forum comes at a propitious time.  There are still heavy weight contributors present in the community, but for whatever reason, they are taking a time-out.  This means you have a chance to establish a presence, if you are so inclined.

Here are some thoughts which may be helpful as you decide how and to what extent you might wish to proceed:

Thanks to the constant attentions of SpaceNut, your "ownership" of the topic you have created is assured.

If someone posts an item in "your" topic, and if you decide it does not fit, you can request that SpaceNut move it to a better topic, if he has not already done  so.

GW Johnson set an example of creating a series of posts which can be read by future forum visitors in sequence.  To facilitate this, GW Johnson edited the posts of the sequence he wanted to collect, by adding "EducationDoneRight" to the posts.   To see the sequence in order, set up a FluxBB search using:
Search: EducationDoneRight Author: GW Johnson

I recommend you consider reviewing GW Johnson's example, both as a guide for your tenure here, and for its content.

Edit: Be sure to select "Posts" instead of "Topics" before Submit.

And! since the default presentation is Most Recent First (Descending), be sure to select "Ascending" before Submit

What I am hoping to persuade you to do, with support of SpaceNut and other forum contributors, is to lead creation of a collection of knowledge which would assist a younger member of the human population to mount an expedition (automated or human) to Apophis, and to carry out scientific and commercial activities there.  At a minimum, your topic here could be a resource for a high school or early college student to use in study of a topic for a paper.

Edit: I am making this declaration AFTER noting the fact that NASA people or people working on a NASA contract have already written a proposal for an expedition to Apophis.  While that paper will certainly be worth study, it is just ONE of many possible approaches.  Your topic here could look at that one, certainly, but plenty of others over the next couple of years.

By now you have seen that SpaceNut has a remarkable ability to scour the Internet for items that relate directly to a post, or which suggest interesting alternative directions to look. 

Organization of your topic here for knowledge purposes would break new ground on this Forum. To my knowledge, no one here has undertaken design of a topic for later consultation by serious students.  My impression is that conversation has been free flowing, with each post stimulating related or sometimes unrelated posts.  In this case, I would invite your consideration of the possibility of design of your topic to flow the way a well designed book would flow, while at the same time welcoming the ad hoc nature of forum contributions.  if you are interested in how this might be done, please let me know.

My order of two books to support development of your topic is due August 30th, Earth time.

(th)

Last edited by tahanson43206 (2019-08-24 07:01:50)

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#42 2019-08-24 09:18:57

SpaceNut
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From: New Hampshire
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Posts: 19,706

Re: Colonizing / terraforming small asteroids

The Nasa paper is designed off from the use of DRM 5 or design reference mission achecture 5 which we do have topics on it as its using the nuclear advabtage to get to a destination more quickly. We are also talking about NEO or near earth objects which are also her as well.
Design Reference Mission 5.0
Near Earth Object (NEO) missions
Nuclear Thermal Rockets (NTR)
Forget NTR, SEP is the Future
Nuclear Transfer Vehicle Design
NASA's Asteroid redirect/retrieval mission; should it be cancelled?
Capturing A NEO
NASA Exploration Roadmaps
BEO mission with artificial graviti & mini-magnetoshpere shielding
Any asteroids with a 365 day orbit around the

There are probably more but what we are getting into is how do we make it so man can stay safely.

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#43 2019-08-25 15:37:39

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,706

Re: Colonizing / terraforming small asteroids

GW Launch window for vehicles that we have for payloads that could be delivered comes to mind...for purpose of planning any mission robotically to man would help.

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#44 2019-09-01 14:58:47

tahanson43206
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Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban re #35 .... both books have arrived here.  They are both well used library copies, perfect for marking up as I like to do.

I invite you to consider how we might use these resources (and others along the way) to create a series of posts which would (or could) provide guidance for a student working on a paper, or (on the high end of the spectrum) for someone thinking about bending education toward a career in the asteroid mining or related fields.

As mentioned previously, GW Johnson is a potential resource for designing a series of posts with educational value.

(th)

Last edited by tahanson43206 (2019-09-01 14:59:12)

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#45 2019-09-02 05:24:40

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 532

Re: Colonizing / terraforming small asteroids

tahanson43206 wrote:

For Calliban re #35 .... both books have arrived here.  They are both well used library copies, perfect for marking up as I like to do.

I invite you to consider how we might use these resources (and others along the way) to create a series of posts which would (or could) provide guidance for a student working on a paper, or (on the high end of the spectrum) for someone thinking about bending education toward a career in the asteroid mining or related fields.

As mentioned previously, GW Johnson is a potential resource for designing a series of posts with educational value.

(th)

Thanks Tahanson.  I have been away from my electronics this past week, so apologies for the late reply.  I will try and devote some time to this now.

I agree with your proposal.  A series of posts would be a good start, ultimately culminating in some papers or perhaps an online book.  Most people here have a scientific or engineering background, so it is a good place to develop ideas on every aspect of 'Near earth asteroid colonisation' concept.  Ultimately, we need something equivalent to the 'Case for Mars' directed towards NEOs.

My original concept of using a polymer net to reinforce an asteroid to allow pressurised tunnelling and artificial gravity, is a tiny subset of a much larger topic.  I therefore suggest keeping this topic close to its original intent and raising others to explore other aspects.  SpaceNut has pointed us towards posts that indicate that there has already been a lot of discussion on individual elements that can be built upon.

Enjoy the books.  I have an old copy of Mining the Sky which I am going to track down.  I am going to see if I can get the other books through my library.


Interested in space science, engineering and technology.

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#46 2019-09-02 08:37:37

tahanson43206
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Re: Colonizing / terraforming small asteroids

Hi Calliban,

Thanks for your reply.

Most of the activity here is hand-to-hand combat.  There is a small amount of supportive cooperation.  SpaceNut is by far and away the best example of that, although SpaceNut participates in hand-to-hand combat with the best of those who so engage here.

You have a choice to make, as the creator of the topic here.  I'd like to invite you to go back to #1 post in this topic, and to add clarifications of the scope of discussion/contribution you'd like to see.  Then (if you are willing) call attention to the edits with a new post.  The purpose would be to insure that the ground rules for the topic are readily available to anyone by simply going to the top (#1) post.

I've highlighted in the quote below a hint at restriction of the topic.  It is important for you to set the boundaries you'd like to invite other members to honor.

(th

Calliban wrote:

I agree with your proposal.  A series of posts would be a good start, ultimately culminating in some papers or perhaps an online book.  Most people here have a scientific or engineering background, so it is a good place to develop ideas on every aspect of 'Near earth asteroid colonisation' concept.  Ultimately, we need something equivalent to the 'Case for Mars' directed towards NEOs.

My original concept of using a polymer net to reinforce an asteroid to allow pressurised tunnelling and artificial gravity, is a tiny subset of a much larger topic.  I therefore suggest keeping this topic close to its original intent and raising others to explore other aspects.  SpaceNut has pointed us towards posts that indicate that there has already been a lot of discussion on individual elements that can be built upon.

Edit: Calliban, after re-reading this post, I realized I'd omitted an important concept: A desired end state for this topic would be helpful.

The topic has the potential to exist for years, if not decades, depending upon factors not under control of SpaceNut, the Mars Society, or anyone else.

Your hint at the possibility of developing packets of knowledge, or inspiration for further study, inspires ME to hope there will be something going on here that I can support to the best of my ability and within limits of time.

(th)

Last edited by tahanson43206 (2019-09-02 08:42:20)

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#47 2019-09-08 06:20:04

tahanson43206
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Registered: 2018-04-27
Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban re topic in general ...

A search of the NewMars archives will show many topics which have been created in a burst of enthusiasm, and which have slowly faded out.

SpaceNut reminds us of some of these meteor traces in the history of the forum, when he brings back links to them, or even refreshes them with new posts when he is moved to do so.

Your topic has significant potential, but it will die the same fate as all the others if you do not tend it.

I recommend you post something to build your topic at least once a week, and most certainly, do NOT depend upon anyone else for incentive. 

The remarkable author Void is an excellent example of self-motivated, sustained contribution.

As reported earlier, I have both of the books I ordered in hopes of supporting your development of your topic, but I am not going to take the lead here.

Leadership of this topic is your responsibility, and I am confident (from your posts here and elsewhere) that you are able to provide it.

What I have no way of knowing (of course) is how much time and energy you have for this project.  You may well be like so many here, trying to provide for family while keeping up a variety of interests.

(th)

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#48 2019-09-08 20:51:43

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 19,706

Re: Colonizing / terraforming small asteroids

Something to consider is not whether we can do such a mission is with what architecture for the price tag for a return of investment.
In this case investment is possibly for precious metals after that its about creating a colony.

Funding method
What size ship payloads
How often can we send missions
Timing for robotic to human involvement

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#49 2019-09-10 03:07:52

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 532

Re: Colonizing / terraforming small asteroids

Tahanson, thank you for your feedback and support on this topic – I am aware that I have not contributed for a while.  My situation is very much as you imagined it to be; three children – all teenagers.  My job is eating more of my time than it usually does and I have been on holiday for a week.

When I started this discussion it was to explore an idea, hopefully with the intent of developing it into something that others will find useful.  I haven't abandoned that intention, but keep in mind that I did not set any timescales as such.  I hope that you have not incurred any expense in support of this; I certainly did not ask you to.

The original concept involved using a polymer bag to stabilise a small asteroid such that internal tunnels could be pressurised without exploding the body and (potentially) to allow the asteroid to spin up to produce artificial gravity; although this proved to be more challenging.  The concept is raised under terraforming, which would be a natural consequence of the project, as we are attempting to recreate an Earth-like environment within excavated spaces.  But the real potential here is to support asteroid mining to deliver materials to Earth orbit and valuable substances to Earth surface.  It allows mining to take place in gravity and in a shirt-sleeve environment; basically using tools that we are familiar with here on Earth.

The original concept involved manufacturing the bag on Earth and delivering it to Earth orbit by heavy lift vehicle.  The bag would be transported to the asteroid using either a chemical stage or some form of electrically propelled transfer vehicle.  The original concept concluded that a spherical asteroid 100m in diameter would require a vectran bag weighing 100te to safely contain internal pressure (assuming 0.5 bar) but this would roughly triple if the asteroid were spun up to produce 0.3g gravity at its equator.  On this basis, a 100m diameter spherical asteroid is probably about the largest we could terraform without using ISRU to produce the bag, given that Musk's starship has a reusable lift capacity of 300te.

One useful topic that we have discussed recently is cyclers.  This adds a new application to the concept.  Cyclers only appear to be useful if a sizable portion of the consumable (especially propellant) for a mission can be derived from the body of the cycler itself.  They also work best if multiple destinations are of interest (i.e. Mars and asteroids).  If the concept can be adapted to cyclers and used to support Mars missions, then Musk could be a key interested party.


Interested in space science, engineering and technology.

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#50 2019-09-10 08:29:24

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 3,527

Re: Colonizing / terraforming small asteroids

For Calliban re #49

<< grin >> If you keep contributing to your topic at this level, I think it is guaranteed to attract other forum members to give it an occasional boost or perhaps trajectory adjustment, and there is an excellent possibility that forum readers who are not yet members will decide to take the plunge to participate.

I am encouraged by your closing paragraph in #49 above .... You have independently arrived at a point which I've been waiting for.  I didn't expect you would decide to look in the direction of adapting an existing asteroid for a cycler application, but was mentally prepared for the possibility, and there it is!

Computing what it would take to adapt Apophis for use as a Cycler is WAY outside my capability, but I'd be surprised if there are not people in the range of the forum who COULD.  For that reason, I am inviting anyone with those skills who is not currently a forum member, to join and give the topic some assistance.

Edit: To be clear, you'll be supporting Calliban and his objectives for this topic, so please ask him how you might be able to assist.

And! [Back to Calliban] Congratulations on the family and on being too busy to get back here often!!!

(th)

Last edited by tahanson43206 (2019-09-10 08:33:14)

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