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#201 2020-03-14 07:50:58

tahanson43206
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Registered: 2018-04-27
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Re: Colonizing / terraforming small asteroids

For Calliban re topic .... your last post was #193 ... SpaceNut and I batted that one back and forth for a while.

Do you have another serve on hand?

This branch of your overall topic seems worth continuing.

At some point the flow may look viable to folks not currently in the forum, who may have some of the background needed to help to develop the concept.

As with the proposal sequence initiated by kbd512 elsewhere in the forum, your topic here has potential to yield a plan or set of plans that would look worth funding to one or more of the billionaires we have on this planet.

At the very least, your topic and the cocoon subtopic has potential to inspire creative thinking and (hopefully) some concrete calculations that could be incorporated into viable plans.

(th)

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#202 2020-03-20 13:48:07

tahanson43206
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Re: Colonizing / terraforming small asteroids

Here is an update on Ryugu ...

https://www.cnn.com/2020/03/19/world/ry … index.html

A relative sent the link.

The article reports on the results of an impact experiment.

(th)

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#203 2020-03-21 07:19:36

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut and all ...

In this time of increased availability of students, professors, professionals and others interested in space development, I am offering this reminder of the vision of "Calliban's Spider" developed in this topic.

The idea is to manufacture basalt thread on site, to wrap Apophis in a cocoon of sufficient strength to allow the asteroid to be accelerated by ordinary chemical rockets.  There is a convenient opportunity to land an "expedition" (of robots) on Apophis, when it passes through the Solar orbital plane inside Earth GEO, in 2029.

Call for Volunteers:

1) Navigation to Apophis, including matching orbits
2) Chemistry of manufacture of basalt thread (if materials are available) or another thread type otherwise
3) Robotics design and programming to:
a) Make thread
b) Deploy thread around the asteroid (see earlier discussion in this topic for alternatives)
c) Secure thread ends
4) Provide solar power for all operations
5) All the other challenges I've overlooked

SearchTerm:CallForVolunteers
SearchTerm:VolunteerOpportunity
SearchTerm:CallibansSpider
SearchTerm:Spider

Last edited by tahanson43206 (2020-03-23 06:27:44)

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#204 2020-03-23 06:26:41

tahanson43206
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Re: Colonizing / terraforming small asteroids

Renewing call for Volunteers to help with "Calliban's Spider"

http://newmars.com/forums/viewtopic.php … 87#p166487
See Post 203 of this topic for details

(th)

Last edited by tahanson43206 (2020-03-23 06:28:13)

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#205 2020-04-01 20:04:29

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re topic ...

This topic deserves to be brought back into view every now and then.

The electromagnetic launcher topic has yielded some nice insights for how an EML would be built to work on the Moon, to toss cargo pods towards Earth or other suitable destinations for further processing.

Basalt is (apparently) available in some abundance on the surface of the near side of the Moon.

https://airandspace.si.edu/exhibitions/ … -rocks.cfm

Distribution of Basalt
Basalt (shown in pink) is not distributed uniformly over the Moon. Nearly 26% of the near side of the Moon is basalt and only 2% of the far side is basalt. Most basalt in either hemisphere is found in areas of lowest elevation, particularly in the very large impact basins.

A mission to wrap an asteroid would be better off if it left the vicinity of Earth to intercept an object fully loaded with basalt thread.  The wrapping operation could begin immediately upon arrival, instead of waiting to try to make thread out of material from the asteroid itself.

(th)

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#206 2020-04-01 20:12:07

SpaceNut
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Re: Colonizing / terraforming small asteroids

True having a cargo of basalt being processed as we go to the asteriod that we would want to cacoon is a plus if we can take it from a place that would not be sensitive to mass removal. We would us ION drive to move the cargo to a destination. It would most likely be nuclear powered to allow for 24/7 around the clock processing of the basalt.
That still leave the desired process means to be decided for wrapping deployment type and for when it will arrive.

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#207 2020-04-02 07:36:45

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut re #206

Thank you for support of this alternative source for basalt.

The supply of the material appears to be substantial, and the potential market for wrapping asteroids is significant.

Investors would have to build the mining, manufacturing and shipping capability on the Moon.

However, once that investment is up and running, any asteroid mining expedition could buy reels of basalt thread delivered to their marshaling location.

(th)

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#208 2020-04-04 13:46:17

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re topic ...

A recent post in kbd512's EML topic shows that an EML that runs at 2.5 G can launch substantial payloads from the Moon with a run of 71 miles.

That is a significant distance, to be sure, but there should be regions on the Moon where a laser straight track could be built to launch payloads towards Earth.

I am imagining a project that includes a basalt thread manufacturing facility on the Moon, the launcher, and a marshaling yard in LEO where an expedition to Opophis would assemble, with the objective of wrapping the asteroid and ultimately, nudging it into an orbit useful for harvesting.

The track, once built, would provide a convenient, comfortable, relatively risk free (and ** very ** inexpensive) facility for passenger traffic from the surface of the Moon.

Edit#1: Length of 2.5 G run was corrected 2020/04/05

(th)

Last edited by tahanson43206 (2020-04-05 12:53:42)

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#209 2020-04-05 05:11:19

tahanson43206
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Re: Colonizing / terraforming small asteroids

This is a follow up to #208 ....

Lunar dust is the issue I'd like to take up for this post ...

An EML, regardless of length, and regardless of design, will pour a lot of energy into the fixed structure, to accelerate whatever the payload package may be.

I would expect electrostatic force to be present, even though the driving force is magnetic.  If there is someone with experience in this field, their input here would be welcome and appreciated.

An EML, regardless of design, will operate with tolerances that are as close as can be achieved in order to maximize transfer of energy from the fixed structure to the moving package.  The greater the gap between the poles of the driving magnets and the driven plate, the lower the efficiency of energy transfer.

My understanding is that lunar dust is remarkably abrasive.  There is no "weathering" going on to round off the jagged projections of fine material.

A design team thinking about building an EML on the Moon would have to consider these factors, along with whatever else goes into design of such a system.

(th)

Last edited by tahanson43206 (2020-04-05 05:12:52)

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#210 2020-04-05 05:55:49

SpaceNut
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Re: Colonizing / terraforming small asteroids

microwave sinter the regolith in the area of the ramp....

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#211 2020-04-05 07:23:35

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut re #210

Following up, I tried "how to microwave sinter lunar regolith" on Google ...

The results were abundant.  I have quoted just a part of the first page:

Did you mean: how to microwave sintering lunar regolith
Search Results
Featured snippet from the web
It is possible to melt lunar soil i.e., 1,200– 1,500° C in minutes in a normal kitchen-type 2.45 GHz microwave, almost as fast as your tea-water is heated.

Microwave Sintering of Lunar Soil - ResearchGate
www.researchgate.net › publication › 228374576_Microwave_Sintering...
Feedback
About Featured Snippets
Web results

Sintered Regolith - Lunarpedia
lunarpedia.org › Sintered_Regolith
... lunar simulant MLS-1 can be successfully sintered using a combination of both microwave and radiant heating.
Lunar Considerations · Radiant Heating · Microwave Heating

Microwave Sintering of Lunar Soil - ASCE Library
ascelibrary.org › doi › (ASCE)0893-1321(2005)18:3(188)
It is possible to melt lunar soil (i.e., 1,200–1,500°C) in minutes in a normal kitchen-type 2.45GHz microwave, almost as fast as your tea-water is heated.

Can you really melt lunar regolith with microwaves? - Space ...
space.stackexchange.com › questions › can-you-really-melt-lunar-reg...
1 answer
Apr 5, 2019 - It is possible to melt lunar soil (i.e., 1200-1500 0C) in minutes in a normal kitchen-type 2.45 GHz microwave, almost as fast as your tea-water is heated.

Sintering of Lunar Soil Simulants Using 2.45 GHz Microwave ...
adsabs.harvard.edu › full
by TT Meek - 1987 - Cited by 9 - Related articles
LPSC XVIII 635 SINTERING OF LUNAR SOIL SIMULANTS USING 2.L15 GHz MICROWAVE RADIATION; T. T. Meek(1), D. T. Vaniman(2), R. D. Blake(3), and ...

Energy would be required to perform this operation, of course, but plenty of energy is going to be needed to power the launcher in any case.

It is not clear (to me at least) how far from the track the regolith would need to be sintered to prevent contamination of the track itself.

It is not clear (to me at least) how much electric field strength is going to exist around the track during operation.    The sintering would need to extend far enough to overcome the power (whatever it is) of the electrostatic force developed on the track.

By the way SpaceNut .... On the Moon, there is no need for a ramp.  The launcher can be laid perfectly flat on the regolith.  All that is required is to have a clear field ahead of the track for whatever distance is needed.  The curvature of the surface of the Moon will see to it that the payload "elevates" in altitude.  It is the same principle as we were discussing with kbd512's original idea of launching horizontally from the surface of the Earth.  If that design were to be implemented on Earth, we have established (earlier in the electromagnetic launch topic) that a run of 400 miles would clear the bulk of the atmosphere.

(th)

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#212 2020-04-05 08:54:17

SpaceNut
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Re: Colonizing / terraforming small asteroids

electrical fields will attact magnetite and iron towards the coils causing them to overload.
The track for the unit will need to be solid as the dust of the moon is powdery so its sintered as well to support the mass of the launch system.
Vertical thrust upward to gain orbit must then come from the rocket thrusters and not the throwing device. So we will want to ramp not level to its surface but towards the orbital plane we want it to get to.
Earths level was due to the plane giving it the climb thrust to gain vertical.

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#213 2020-04-05 10:03:43

tahanson43206
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Re: Colonizing / terraforming small asteroids

For SpaceNut re #212

No rockets are required. 

No vertical thrust is required.

There is no atmosphere on the Moon, so a set of wings is not needed.

A launcher 71 miles long, operating at a comfortable 2.5 G's for passengers, can deliver a vehicle to Lunar Escape velocity.

Edit#2: Lunar Escape velocity is given (by Google) as: 2,380 meters per second

From its equator, the Moon has a radius of 1 738 km. It also has an estimated mass of 7.342 × 1022 kg. This means that the Moon's escape velocity is 2.38 km/s. That is much less than the 11.2 km/s it takes to get off the Earth.Jul 23, 2019

Escape Velocity | Let's Talk Science

Edit#1: The time for a vehicle to move from the start of the launcher to exit is 97 seconds and change.

SearchTerm:LunarLaunch
SearchTerm:LaunchMoon
SearchTerm:EMLMoon

(th)

Last edited by tahanson43206 (2020-04-05 12:51:43)

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#214 2020-04-05 11:18:52

SpaceNut
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Re: Colonizing / terraforming small asteroids

The track length has little meaning to the launch speed of just 2.5 g's as a g is 9.8m/s2 for earth and when you look at the launch speed to orbit the moon is 1.78 km/s for low lunar orbit of an altitude of about 60km -100km and to leave the moon its nearer to 2.8 km/s....Mach 5 speed corresponds to 1.5 km/s. 

the moon's g drag on acceleration is 1.625 m/s2. If the g-force on lunar liftoff is about 0.5g, that would be three times normal lunar gravity, the equivalent of 3g acceleration after liftoff from Earth. In this case for the 2.5g you wanted we would be feeling 6 times greater value and thats not at all comfortable.


https://softschools.com/formulas/physic … ormula/90/

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

objects follow the curvature of gravity of an object so the ramp leangth needs to rise above the horizon level to not follow the curve addition angle makes it possible to get to the orbit distance for teh velocity along the arc path to orbital insertion and if its to high it travels away from the moon on an endless journey until gravity pulls it away from its path.

https://ntrs.nasa.gov/archive/nasa/casi … 007073.pdf
A Lunar Electromagnetic Launch System for In-Situ Resource

https://repositories.lib.utexas.edu/handle/2152/32979
Abstract: This paper details a lunar surface electromagnetic launcher concept and supporting systems which delivers one metric ton of lunar-derived liquid oxygen to low lunar orbit per payload launch.

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

You will still need thruster for manueveriung control.

https://www.researchgate.net/publicatio … _Launchers

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#215 2020-04-30 09:13:11

tahanson43206
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Re: Colonizing / terraforming small asteroids

It's been a while since Calliban updated this important topic. 

The latest issue of Analog contains a fact article about the deduced history of asteroid collisions that resulted in debris of various sizes that impacted the Earth 466 million years ago, and may have caused an out-of-turn ice age due to the vast quantity of dust created by the collision.

The article concludes with a speculation that an asteroid might be nudged into the Earth-Sun L1 position, and then stimulated to produce dust to interfere with the flood of solar radiation reaching the Earth.

I thought at the moment I read that passage, that "Calliban's Spider" would be helpful in doing the nudging.

The only thought the author had on that subject was the tired old idea of using a "gravity tractor". 

(th)

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#216 2020-06-03 03:17:02

Calliban
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Registered: 2019-08-18
Posts: 551

Re: Colonizing / terraforming small asteroids

Where some see a problem, others see an opportunity.
https://www.zerohedge.com/markets/pande … -asteroids

These four asteroids are small enough to be cocooned using a net that is manufactured on Earth and delivered by a heavy lift vehicle.


Interested in space science, engineering and technology.

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#217 2020-06-03 03:49:21

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 551

Re: Colonizing / terraforming small asteroids

tahanson43206 wrote:

It's been a while since Calliban updated this important topic. 

The latest issue of Analog contains a fact article about the deduced history of asteroid collisions that resulted in debris of various sizes that impacted the Earth 466 million years ago, and may have caused an out-of-turn ice age due to the vast quantity of dust created by the collision.

The article concludes with a speculation that an asteroid might be nudged into the Earth-Sun L1 position, and then stimulated to produce dust to interfere with the flood of solar radiation reaching the Earth.

I thought at the moment I read that passage, that "Calliban's Spider" would be helpful in doing the nudging.

The only thought the author had on that subject was the tired old idea of using a "gravity tractor". 

(th)

An alternative idea to the cocooning spider, would be to manufacture the net in sections under controlled conditions.  The sections can then be coupled together and the same couplings could be used to tighten the net around the asteroid.  That way, the manufacture of the net can be carried out in a module equipped with gravity and life support, which allows for better quality control and maintenance of equipment.  The couplings themselves would probably include some sort of long bolt, that can be tightened to generate the required amount of tension in the net.

In this way, it is possible to build huge nets, encompassing large asteroids, from simple segments manufactured in a relatively small facility.  The segments could be decoupled and reused when mining is completed.  The entire manufacturing facility could be moved on to a different asteroid using waste reaction mass from mining, when the cocoon is completed.

Last edited by Calliban (2020-06-03 03:59:42)


Interested in space science, engineering and technology.

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#218 2020-06-03 05:53:28

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re #217

Thanks for this nice addition to the topic!

I particularly like the re-use proposition.  Picking up on this a bit ... these could be "intelligent" nets ... the perimeter could be populated by small cubesat sized thruster/navigator systems designed to operate as a pack, as has been demonstrated on Earth with large numbers of small drones.

At deployment, the net "packs" could be given instructions to coordinate with other net packs, to perform enclosure maneuvers without human supervision, except for debugging the instructions as seems likely to occur from time to time.

One concern I'd like to toss back is whether the proposed nets would have the collective strength to permit acceleration of the entire mass, as would be needed to perform an orbit change.  The spider wrapping would seem (to me at least) likely to have the required strength, but I admit that the net concept has a better chance of enclosing the mass completely in a single coordinated flight plan.

Bravo!

Also ... since your visits here are infrequent, I'd like to invite your consideration of a question posed in the Balloon/Phobos topic.  I'm considering using aluminum as the material for cushions between links of Kevlar thread for a tether.  My question is: Does Aluminum have the strength in compression to withstand the forces that would be at play?  The cushions would be (approximately) 2 meter diameter spheres, subject to compression of 60 metric tons of mass in the 38% Mars gravity.  I am wondering if the Aluminum would squirt out like putty under those conditions.

Please reply in the Balloon/Tether topic if you have time.

Thanks!
(th)

Last edited by tahanson43206 (2020-09-19 06:27:23)

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#219 2020-06-03 16:05:52

SpaceNut
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Re: Colonizing / terraforming small asteroids

AG testing is still a need to be done for any device that will make use of how gravity must work for a microgravity environment of orbiting a large rock.

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#220 2020-09-19 04:13:30

Calliban
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Posts: 551

Re: Colonizing / terraforming small asteroids

Kbd's proposed fusion propelled vehicles and Musk's apparently realistic plan to reduce launch costs to $10/kg, open a lot of options here.  For initial projects, we would make the nets on Earth and deliver them to the target asteroids.  If transport costs are really that low, it makes sense to do this rather than attempt to manufacture the net insitu under more difficult conditions.  We would then install glass fibre manufacture and weaving machines in the tunnels, where we would be working in spin gravity with an atmosphere.  Whilst we are mining and hollowing out the asteroid, we would be manufacturing the net we need for the next mission.


Interested in space science, engineering and technology.

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#221 2020-09-19 06:34:31

tahanson43206
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Re: Colonizing / terraforming small asteroids

For Calliban re #220

It is good to see you bring this (to me important) topic back into view.

This post is an anchor for information I hope to collect about robots that can weave webs, which I ran across recently.

The original idea discussed at some length, of wrapping an asteroid of loosely bound rubble in a cocoon of basalt thread still seems attractive to me, but advances in robotics appear to offer the even better option of weaving a web at the surface.   In that scenario, multiple robot weavers could build a web in their location, and all the webs would be joined together to make a seamless wrapping for the entire bundle of useful material.

That wrapped bundle could then be given gentle acceleration by suitable equipment, to put the collection on a path to a processing facility.  This technique could be used throughout the Solar system.

The material to be shipped from Earth would then consist of the robot weavers and their supply of thread, instead of already-woven mats which would have to be manipulated on site.

SearchTerm:AnchorRobotWeaver

(th)

Last edited by tahanson43206 (2020-09-19 06:35:09)

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