RE: Asteroid mining (Full Version)

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Karmastic -> RE: Asteroid mining (4/27/2012 6:24:47 PM)

quote:

ORIGINAL: DomKen
Nope. Most radiation is stopped by a sheet of aluminum foil and most of the rest is deflected by the Van Allen.

Great, can we use our tin foil hats in a pinch?



SoftBonds -> RE: Asteroid mining (4/27/2012 6:55:53 PM)


quote:

ORIGINAL: hardcybermaster

to be fair, the space shuttle is specifically designed to be able to re enter the earths atmosphere, an asteroid isn't, if it's designed to do anything it's to make a fuck off big crater


Which was essentially the problem under discussion. Whether intentional (oops, sorry N. Korea) or unintentional.
Robert Heinlein in "The moon is a harsh mistress," wrote about a lunar nation dropping rocks on the Earth, and had Asimov double check the math. Heinlein being an engineer, and Asimov a respected scientist. Damage from a "falling rock," was expected to be "only," the equivalent of Hiroshima, though without the radiation.
I think it was a 100 ton falling rock for that damage. I don't have a copy of the book handy though.
As for burning up or being deflected, that is a problem for the space shuttle because it wants to land without a boom. If you aim directly at Earth, or even close, the rock will fall down, and if it is large enough, hit the surface. Yes, if you throw it at a sufficient angle you can bounce an asteroid off the atmosphere or slingshot it, but that is harder than just hitting the earth. Gravity, it works Bitches!
Angle of approach can increase the amount vaporized by re-entry, but again, the larger the mass, the more gravity will help pull it on a straight course down. Also, the re-entry heat is caused by wind resistance, last I checked, "for every action, there is an equal and opposite reaction from a mother in law" meaning that the rock is slowed down by the resistance. Since it continues to have acceleration from gravity, but no acceleration tangent to earth, it will "curve," down.
At the end of the day, mass is the question, if the rock is big enough, it can make a big boom. If it isn't, it will burn up and make pretty lights in the sky.



FrostedFlake -> RE: Asteroid mining (4/28/2012 2:30:47 AM)

quote:


quote:

2. No mention, so far, of a superconducting electromagnet to deflect cosmic and solar radiation. Can't live without one of these. Can't mine ferrous metal if you do have one.

There's no long trip, so the radiation isn't really an issue. If any long-term, non-robotic operations on the asteroid after recovery were needed, the asteroid itself would serve as passive shielding. As an aside, passive shielding is generally seen as the practical protection from radiation for human deep-space travel, not active electromagnets.




quote:

DomKen

quote:

ORIGINAL: FrostedFlake
2/ No mention, so far, of a superconducting electromagnet to deflect cosmic and solar radiation.

Can't live without one of these. Can't mine ferrous metal if you do have one.

Nope. Most radiation is stopped by a sheet of aluminum foil and most of the rest is deflected by the Van Allen. The miners are going to work in Earth orbit after the rocks are brought there by robot craft.

The Apollo crews went beyond the Van Allen in essentially a tin foil box and did not get a big enough radiation dose to cause any problems. They certainly did not have anything like a superconducting magnet onboard.


http://en.wikipedia.org/wiki/Rad_(unit)

http://lsda.jsc.nasa.gov/books/apollo/s2ch3.htm

http://www.space.com/3033-report-space-radiation-concern-nasa-exploration-vision.html

http://www.space.com/2367-space-travel-industry-data-radiation-risk.html

http://www.space.com/2124-model-predicts-intense-solar-storms.html

http://www.space.com/2361-scientists-ponder-space-superstorm.html

http://en.wikipedia.org/wiki/Radiation_protection

http://www.nap.edu/openbook.php?record_id=12045

I could go on for a while. I was a Submariner. I know a little about radiation. Alpha can be stopped with paper. Hooray. Beta can be stopped with a 1/4 inch of aluminum, but, doing that creates X-rays. Ooops. Gamma may be thought of as ultra, super, quite really very high frequency radio waves. Of up to 10 million electron volts energy. On a Submarine. On a spacecraft, Gamma can reach energies a million times higher. Up there you also find Cosmic Radiation and X-rays, both similar enough to Gamma that you can lump them together and all susceptible to magnetic fields.

http://www.physicamedica.com/VOLXVII_S1/17-TOWNSEND.pdf

http://physicsworld.com/cws/article/news/2008/nov/06/magnetic-shield-could-protect-spacecraft

quote:

DomKen
The Apollo crews went beyond the Van Allen in essentially a tin foil box and did not get a big enough radiation dose to cause any problems. They certainly did not have anything like a superconducting magnet onboard.


The Apollo crews were in space days. About a week. Not months or years. And some of them got cataracts. A radiation effect. Here is the radiation:

ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SOLAR_FLARES/FLARES_INDEX/McMath/CFI55_80.TXT

Here is the cliffs notes version.

http://www.youtube.com/watch?v=T1ltWMbHdDU

Bottom line : Above 300 miles and you are on your own. So, I don't know, you might want to wear a hat. Tinfoil, if that is what you think it takes.

Moving on:
quote:

Kalikshama
I've been hearing a lot about mining asteroids for ***water*** lately and would like someone to explain how this can possibly have a better ROI than investing in conservation or desalination here on Earth.

There was a mention of getting rocket fuel from separating the H and Os; perhaps someone would be so kind as to expound on this.


Basically, there's water in them there hills. Getting it out is a mining process, much like mining for anything else. The value is that it wasn't brought from Earth, at $10,000 a pint (That is just to low Earth orbit). So it could be said to be worth $10,000 a pint. Or more. Splitting water into H2 and O2 (rocket fuel and fuel cell fuel) is a matter of applying a small voltage. Ideally 1 & 1/4. At high current. Perhaps from a solar panel. This is between 50% and 80% efficient, the rest goes to heat. A fuel cell is about 50% efficient also, but heat on a spaceship is often welcome and so is the H2O the fuel cell generates.

http://www1.eere.energy.gov/education/pdfs/solar_electrolysisofwater.pdf

http://en.wikipedia.org/wiki/Electrolysis

And that should bring us to here:

http://www.youtube.com/watch?v=hWHwI-Hvpzo

Later.



MrBukani -> RE: Asteroid mining (4/28/2012 2:59:10 AM)

First question is, Who owns space? Is it gonna be like earth and just grab and claim it yours, is that what we want.
Like I have heard people are buying plots on the moon, from fuckin who? Who has the authority to sell space?
Second question. This research has been going on a long time. Twenty years ago some company identified an asteroid in space wich might be pure gold or something. Besides the point this might be hogwash.
What if they find a resource that has twice the amount of gold then earth has at present.
What would that do to the economy and goldprices?
Before we start mining space we should get our shit together on earth. So that our economy cant be destroyed by companies hunting for profit.



DomKen -> RE: Asteroid mining (4/28/2012 7:17:49 AM)


quote:

ORIGINAL: FrostedFlake
<snip a whole lot>

You greatly eagerating the amount of dangerous radiation.

There's very little high energy beta or gamma in LEO. Even outside the Van Allen the levels are low except during major solar activity and the levels involved then are still a bigger threat to electronics than to people.



Muttling -> RE: Asteroid mining (4/28/2012 9:00:55 AM)

Maybe they'll find the green babe that Captain Kirk nailed....

[image]http://www.hecklerspray.com/wp-content/uploads/2008/10/yvonne_craig_as_slave_girl_marta1.jpg[/image]


Or the Droxine chick with the radiation reflected bra....

[image]http://www.hecklerspray.com/wp-content/uploads/2008/10/cldmndrs604r1.jpg[/image]




FrostedFlake -> RE: Asteroid mining (4/28/2012 1:35:04 PM)


quote:

ORIGINAL: DomKen


quote:

ORIGINAL: FrostedFlake
<snip a whole lot>

You greatly eagerating the amount of dangerous radiation.


If you will notice, it wasn't me that did any "exaggerating". I didn't make claims or assertions. I made citations. Like this one.

http://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays

quote:

There's very little high energy beta or gamma in LEO.


Low Earth Orbit is inside Earths Magnetosphere. The magnetosphere deflects Cosmic and Solar Radiation.

I said this.

quote:

Even outside the Van Allen the levels are low except during major solar activity...


Low... relative to levels observed DURING major solar activity. Cosmic rays are constant and relatively low in intensity while solar radiation spikes heavily frequently. I notice you have conveniently skipped the Van Allen Radiation Belts.

http://www-spof.gsfc.nasa.gov/Education/Iradbelt.html

quote:

...and the levels involved then are still a bigger threat to electronics than to people.


So, ... I should worry more about my radio being destroyed by radiation than about my health? What are you trying to say here and how does that support your point, which I paraphrase as "Radiation? What Radiation?"

Look. We don't need to argue. You can review my citations or show me yours. If you want to believe what you want to believe, then you go right ahead.

And "Bless your heart"



DomKen -> RE: Asteroid mining (4/28/2012 3:13:24 PM)

Read your own sources.
quote:

The potential acute and chronic health effects of space radiation, as with other ionizing radiation exposures, involve both direct damage to DNA and indirect effects due to generation of reactive oxygen species. Acute (or early radiation) effects result from high radiation doses, and these are most likely to occur after solar particle events (SPEs).[12] Likely chronic effects of space radiation exposure include both stochastic events such as radiation carcinogenesis [13] and deterministic degenerative tissue effects. To date, however, the only pathology associated with space radiation exposure is a higher risk for radiation cataract among the astronaut corps

IOW stay out of solar storms and stay inside the Van Allens and you have next to nothing to worry about. Since the asteroid miners are specifically planning on keeping to earth orbit that is what we're concerned with.

And no matter what a electromagnet would do nothing to the dangerous particles because they are going so fast unless it had a multi megawatt power source which is presently impossible for spacecraft. The ISS's shielding is effectively aluminum foil and is considered sufficient for its location.



kalikshama -> RE: Asteroid mining (4/28/2012 5:24:10 PM)

quote:

First question is, Who owns space? Is it gonna be like earth and just grab and claim it yours, is that what we want.
Like I have heard people are buying plots on the moon, from fuckin who? Who has the authority to sell space?


This was covered in the NPR piece I posted above. While no one can claim sovereignty or celestial bodies, Planetary Resources feels they are not prevented from mining.

http://en.wikipedia.org/wiki/Outer_Space_Treaty



kalikshama -> RE: Asteroid mining (4/28/2012 5:27:16 PM)

quote:

It's where the water would be at. "Mining" it from an asteroid would save having to launch the stuff into earth orbit.

But how could it possibly be more cost effective than conserving earth resources?

quote:

A fairly basic, and very energetic, rocket fuel is liquid O2 and liquid H2. Basically the two gases are mixed in the engine and burned. As water is H2O it is possible to use electricty to break the chemical bonds and get O and H.

Or would the point just be to generate fuel for other mining operations?



DomKen -> RE: Asteroid mining (4/28/2012 8:08:33 PM)


quote:

ORIGINAL: kalikshama

quote:

It's where the water would be at. "Mining" it from an asteroid would save having to launch the stuff into earth orbit.

But how could it possibly be more cost effective than conserving earth resources?

quote:

A fairly basic, and very energetic, rocket fuel is liquid O2 and liquid H2. Basically the two gases are mixed in the engine and burned. As water is H2O it is possible to use electricty to break the chemical bonds and get O and H.

Or would the point just be to generate fuel for other mining operations?

The point is that any sort of permanent human activity in orbit requires a large amount of water. That water either has to be lifted up from the Earth by way of rockets, a very expensive process that reduces what other items can be lifted on the limited number of launches that can be done, or it can be produced in orbit by way of mining.



TheHeretic -> RE: Asteroid mining (4/28/2012 8:36:52 PM)


quote:

ORIGINAL: kalikshama

quote:

It's where the water would be at. "Mining" it from an asteroid would save having to launch the stuff into earth orbit.

But how could it possibly be more cost effective than conserving earth resources?

quote:

A fairly basic, and very energetic, rocket fuel is liquid O2 and liquid H2. Basically the two gases are mixed in the engine and burned. As water is H2O it is possible to use electricty to break the chemical bonds and get O and H.

Or would the point just be to generate fuel for other mining operations?



Two things, Kalikshama. We don't want to mine water in space to send back to Earth, but to use in space. The only reason to bring it down would be for research, and as an insanely expensive novelty drink, in the sorts of bars where billionaires show off for each other.

Second, the mining is far from an end in itself. The ability to conduct industrial activity in space is just one step in really starting to get out and explore.



FrostedFlake -> RE: Asteroid mining (4/30/2012 11:30:49 PM)


quote:

ORIGINAL: DomKen

Read your own sources.
quote:

The potential acute and chronic health effects of space radiation, as with other ionizing radiation exposures, involve both direct damage to DNA and indirect effects due to generation of reactive oxygen species. Acute (or early radiation) effects result from high radiation doses, and these are most likely to occur after solar particle events (SPEs).[12] Likely chronic effects of space radiation exposure include both stochastic events such as radiation carcinogenesis [13] and deterministic degenerative tissue effects. To date, however, the only pathology associated with space radiation exposure is a higher risk for radiation cataract among the astronaut corps

IOW stay out of solar storms and stay inside the Van Allens and you have next to nothing to worry about. Since the asteroid miners are specifically planning on keeping to earth orbit that is what we're concerned with.

And no matter what a electromagnet would do nothing to the dangerous particles because they are going so fast unless it had a multi megawatt power source which is presently impossible for spacecraft. The ISS's shielding is effectively aluminum foil and is considered sufficient for its location.

See, Kids? This is why you should not argue on the internet.

1/ I referred to the citation presented and presented the citation referred to, yet, here it is being held up to 'prove' I was wrong when I did.

2/ Mining an object in Lunar orbit from low Earth orbit is an interesting suggestion. But even there is not so safe. NASA imposes a 160 day lifetime limit on spaceflight.

3/ Don't take it from me, look instead at what the rocket scientists have been discussing very seriously for more than 20 years.

http://www.islandone.org/Settlements/MagShield.html

It is fortunate I need not 'win' this argument. I can't imagine how to get there from here. I have a new sympathy for the dog who barks at his echo.



DomKen -> RE: Asteroid mining (5/1/2012 6:33:04 AM)


quote:

ORIGINAL: FrostedFlake


quote:

ORIGINAL: DomKen

Read your own sources.
quote:

The potential acute and chronic health effects of space radiation, as with other ionizing radiation exposures, involve both direct damage to DNA and indirect effects due to generation of reactive oxygen species. Acute (or early radiation) effects result from high radiation doses, and these are most likely to occur after solar particle events (SPEs).[12] Likely chronic effects of space radiation exposure include both stochastic events such as radiation carcinogenesis [13] and deterministic degenerative tissue effects. To date, however, the only pathology associated with space radiation exposure is a higher risk for radiation cataract among the astronaut corps

IOW stay out of solar storms and stay inside the Van Allens and you have next to nothing to worry about. Since the asteroid miners are specifically planning on keeping to earth orbit that is what we're concerned with.

And no matter what a electromagnet would do nothing to the dangerous particles because they are going so fast unless it had a multi megawatt power source which is presently impossible for spacecraft. The ISS's shielding is effectively aluminum foil and is considered sufficient for its location.

See, Kids? This is why you should not argue on the internet.

1/ I referred to the citation presented and presented the citation referred to, yet, here it is being held up to 'prove' I was wrong when I did.

2/ Mining an object in Lunar orbit from low Earth orbit is an interesting suggestion. But even there is not so safe. NASA imposes a 160 day lifetime limit on spaceflight.

3/ Don't take it from me, look instead at what the rocket scientists have been discussing very seriously for more than 20 years.

http://www.islandone.org/Settlements/MagShield.html

It is fortunate I need not 'win' this argument. I can't imagine how to get there from here. I have a new sympathy for the dog who barks at his echo.

1) What you said was wron g or at the minimum exagerated.
2) no one is talking about doing anything in lunar orbit. As to a 160 day limit, I have no idea where you get that but a quick check of ISS missions show numerous US astronauts that spent more than 160 days on the ISS. Michael Fossum (one of our recent ISS crew members) has a total of over 193 days in LEO.
3) Yes, scientists have talked about more shielding for interplanetary missions. That's due to those proposed missions being multi year long and occuring outside the Van Allens. But as I've now shown repeatedly is not a concern in LEO.



FrostedFlake -> RE: Asteroid mining (5/1/2012 10:40:45 AM)

Ken. No one is going to bring an asteroid into low earth orbit.

I'm going to let the rest go.

I should not have to post on this thread again.



DomKen -> RE: Asteroid mining (5/1/2012 1:14:14 PM)


quote:

ORIGINAL: FrostedFlake

Ken. No one is going to bring an asteroid into low earth orbit.

And I didn't say they would bring a rock into LEO. However they do state that they intend to bring rocks into Earth orbit.

from the original article
quote:

At some point, the company would have enough information to launch spacecraft built to travel to an asteroid and retrieve them over several years, ultimately delivering them to a high Earth orbit



hardcybermaster -> RE: Asteroid mining (5/1/2012 3:53:41 PM)

quote:

ORIGINAL: FrostedFlake

Ken. No one is going to bring an asteroid into low earth orbit.

I'm going to let the rest go.

I should not have to post on this thread again.

find another tiger pic, everything will be better then



xssve -> RE: Asteroid mining (5/1/2012 4:50:36 PM)

It's a great idea, once you have water up there you just have to recycle it - the real problem is the loss of bone and muscle mass from living in zero G for extended periods.

I think the possibilities of zero manufacturing are more interesting even than the mining though, there are a lot of ways you can play with the crystalline structure of metals and ceramics that you can't do at gravity.



shallowdeep -> RE: Asteroid mining (5/1/2012 11:41:22 PM)

Radiation is obviously a concern that deserves consideration when in space, especially if not in equatorial LEO, but you did start off by writing that it would be impossible to live without "a superconducting electromagnet to deflect cosmic and solar radiation." Taken literally, that was, at best, an exaggeration.

Some solar flares could potentially be lethal to astronauts with no protection, but it's relatively easy to shield against the resulting solar particle events and the risk of any acute effect while inside a spacecraft is considered to be extremely unlikely. [Source: Risk of Acute Radiation Syndromes Due to Solar Particle Events]

The other major concern, galactic cosmic rays, are much more challenging to shield against due to the production of extensive secondary radiation, but the radiation is present at significantly lower levels and would not cause any acute early effects. The risk with GCRs is confined to late effects: namely cancer, but also gradual tissue damage to the eye's lens and potentially to the central nervous system. Because the biological effects of high energy heavy ion (HZE) impacts can't be studied on Earth outside of particle accelerators (that physicists are undoubtably loathe to share with mere biologists), there's still a fair bit of uncertainty about what quality factor cosmic radiation, and the HZE particles in particular, should be assigned. Still, it's clear exposure is not going to be an immediate risk to life. As part of planning for a trip to Mars, NASA studied the issue in 2001. Using the guideline that a 3% increase in cancer mortality above the background of average cancer mortality in the US population would be an acceptable level of risk, the report calculated that, with only standard shielding, there is 95% confidence that it would take 268 days or more of exposure for a 55-year-old male to reach that risk level – but the exposure duration would be less for younger astronauts and for females. [Source: Space Radiation Cancer Risk Projections For Exploration Missions]

For trips to a nearby captured asteroid, the radiation risk really isn't a show-stopper. For longer trips, like to Mars, it might well be. In 2004, NASA put the most probable cancer risk of a 1000-day mission at 3.4%, but with uncertainty ranging from 1% to 19%. [Source: Can People Go to Mars?] Those sorts of extended deep space trips are where massive or novel radiation shielding against GCRs could be required.

Passive mass shielding currently seems closer to being practical than any active shielding scheme, and has the benefit of being simple and guaranteed to work. The obvious downside is getting the required mass into space. To heavily shield a practically-sized crew compartment would require around 400 tons of mass by one calculation. [Source: Shielding Space Travelers] That's the equivalent of the entire ISS (or two Saturn V-equivalent payloads) just for the shielding, probably cost prohibitive with NASA's current budget and lift capacity.

The motivation behind active shielding is that it might reduce the expensive mass required, but despite more than 40 years of investigation, it's not yet clear that any proposed design would actually be able to do that, even assuming the significant technical issues posed could be overcome. From the 2000 Townsend paper you cited earlier: "None of the active shielding methods proposed to date appear to offer a weight savings over bulk material shielding when considering the entire deep space environment." Similarly, a group of experts convened by NASA to investigate revolutionary alternatives for shielding concluded in 2005 that "none of the electromagnetic concepts showed clear promise." [Source: Revolutionary Concepts of Radiation Shielding for Human Exploration of Space] Some of the ideas are interesting and admittedly kind of cool, but at best they are still a ways away from any practical realization.

Mining asteroids, if it pans out, actually promises a solution to the shielding problem: If it need not be launched from Earth, shielding mass suddenly becomes much more affordable. Besides use as a fuel, enough water from an asteroid could also make very effective shielding for a crewed spacecraft.

quote:

ORIGINAL: FrostedFlake
I know a little about radiation… Up there you also find Cosmic Radiation and X-rays, both similar enough to Gamma that you can lump them together and all susceptible to magnetic fields.

I see. Is it the electric charge of a photon, or a photon's mass that makes it susceptible to magnetic fields? Can we lump gamma rays with cosmic rays because of the close similarity in mass? Or was it in velocity? Or maybe just that they both have the word "ray" in the name? Why didn't my EM theory classes or health physics text cover this stuff! :)



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