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So You Want to Buy an Asteroid...

04/06/2013 9:37 AM

Now here's something I can really get on board with, towing asteroids into close Earth orbit....All those mineral supplies....I think we should get 100's of them....

"

NASA unveils plans to tow asteroid into Earth's orbit for astronauts to explore: senator

Florida Sen. Bill Nelson said Friday $100 million of President Obama's budget will be set aside for the space mission. The two-phased plan would help put an astronaut on an asteroid by 2021, four years ahead of Obama's previous goal.

WASHINGTON - NASA has an idea straight out of "Star Trek" - and President Obama is proposing to spend an initial $100 million to make it happen.

The space agency is developing plans to launch a robotic spaceship that would rendevouz with a small asteroid and tow it toward earth for spacewalking astronauts to explore.

U.S. Sen. Bill Nelson (D-Fla.), a former astronaut, revealed the "audacious" plan Friday after meeting with NASA scientists.

"It really is a clever concept," Nelson told a news conference in Orlando. "Go find your ideal candidate for an asteroid, go get it robotically and bring it back."

Obama will place an initial $100 million for the mission in the 2014 budget that he'll propose next week.

The money will be used to plan the mission and identify a suitable asteroid to explore - ideally, one that is 25-feet wide and weighs about 500 tons."

http://www.nydailynews.com/news/national/nasa-plans-tow-asteroid-earth-orbit-article-1.1309163#ixzz2Pgq0UEqX


Now we just have to figure out how to get them down....

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#1

Re: So you want to buy an asteroid....

04/06/2013 12:09 PM

Ya, f-ing great idea. We have to hitch-hike a ride to the ISS, so I guess that problem is solved, no need to spend money there. And the "initial 100 mil", chump change. Just some kick-back to major campaign contributors.

Times have changed. China, (and others), have their sights upon the Moon, and beyond.

The US wants to collect space pebbles.

That said, I think we should do it*, get back in the game.

*by the end of the decade

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#2

Re: So You Want to Buy an Asteroid...

04/06/2013 1:12 PM

Only problem? As Bricktop said, money. Oh, and technology. Oh, and time. And and and..........................

Don't worry about our educational system, which is in ruins, don't worry about the thousands of meth addicts that steal millions of dollars worth of copper wire EVERY MONTH OF EVERY YEAR. No! Just throw them in jail. Wait, there's no money for more jails. There's no money for education and eradication of dangerous , let me repeat that DANGEROUS drugs. That does not include pot, by the way.

Oh, that's right, there's no money in rehabilitation and REAL drug deterrent programs so wall street, the banks that are too big to fail, lawyers and politicians just can't get rich enough off of worthwhile causes.

Let's just go play in space and do something that HAS NO PRACTICAL VALUE AT ALL. That'll take our minds off the reals problems we face.

Don't even start me on illegal immigrants.

Rant switch off.

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#18
In reply to #2

Re: So You Want to Buy an Asteroid...

04/08/2013 2:11 PM

You have an off switch???

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#3

Re: So You Want to Buy an Asteroid...

04/06/2013 1:17 PM

In a way I think its a rather good first step. If you think about it the metallic asteroids tend to contain rather large volumes of nearly pure metals and many of those metals are the higher valued ones we need for our modern way of life. Those same metals that have high prices mostly due to world government politics which accounts for trillions of wasted dollars annually.

To me if even 1/4 of the money wasted on the world politics behind the rare earth and other highly sought after metals trade in the last decade was put into the space based mining research and development the odds are we would already have a number of orbiting asteroids being mined and processed in space already.

BTW when spread out over the whole US population a $100 million budget means we each chip in about 30 cents. I for one will happily skip buying those two 25 cent gumballs next time I am at the mall with my niece to help fund this project and then some!

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#4

Re: So You Want to Buy an Asteroid...

04/06/2013 3:33 PM

They used to plan to use a rocket to divert an object away from earth so that all life will not be extinguished by the object when it impacts. Now they want to pull it in. Tell me why is this a good idea again?

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#5
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Re: So You Want to Buy an Asteroid...

04/06/2013 5:32 PM

Because we can survive a 500 ton oops hitting the ground in a somewhat controlled trajectory. Thats why.

It would also be a good engineering exercise in learning how to control larger masses in space so we can better deal with controlling an unintentional 500,000 ton asteroid should it come our way some day.

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#6
In reply to #5

Re: So You Want to Buy an Asteroid...

04/06/2013 5:55 PM

It seems like making use of it to build materials needed in orbit might be a better use.

It costs roughly 11,000 dollars a pound to bring things into orbit. While I realize that refining and manufacturing in space are not technologies yet well developed, it seems like it would be a good avenue to explore, with the possibility of avoiding altogether the 'hitting the ground in a somewhat controlled trajectory'.

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#7

Re: So You Want to Buy an Asteroid...

04/06/2013 9:34 PM

Well it might be a rather good investment....

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#8
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Re: So You Want to Buy an Asteroid...

04/06/2013 9:47 PM

This Is How Asteroid Mining Will Work


"Yesterday, a group of billionaires, scientists and engineers announced what could become the most important enterprise in human history since Columbus sailed West:an asteroid mining company called Planetary Resources. They want to jump start a completely new industry between the Earth and the Moon, one that will add trillions of dollars to the world economy and ensure our prosperity for centuries to come.

Is an amazing and lofty goal. One that has the potential to change our world forever. One that is risky and hard, but which they believe can be achieved within a decade. This video offers a glimpse of how space mining will work.

The tycoons

Planetary Resources is backed by people with deep pockets, like Google's Larry Page and Eric Schmidt, film maker James Cameron, Microsoft's former Chief Software Architect Charles Simonyi, and Ross Perot, Jr. among others.

The target

There are 9,000 asteroids near Earth. Of those, about 1,500 are within easy reach using the same or less power than what was used to go to the moon.

The benefits

These asteroids are loaded with two things. Some of have a high content of water ice, which could be converted into solid oxygen and solid hydrogen to provide rocket fuel for exploration; in its un-altered form, it could help support life in space. Harvesting water from asteroids will make space travel really inexpensive, allowing for an industry to blossom in space.

Other asteroids are rich in rare metals, like platinum or gold. An abundance of these metals will enable easier access to technology that is currently prohibitively expensive.

One small asteroid of, say, 50 meters in diameter could contain billions of dollars worth of these metals, pure and ready for easy extraction. Likewise, an icy asteroid of the same size could contain enough water to power the entire space shuttle program.

The process

First, within two years, the company will send prospectors to low-earth orbit. Called the Arkyd 100 series, these machines will be cheap and networked together. They will track near earth asteroids (NEA) and asses the possibility to reach them and mine them.

Within a decade, they will launch a swarm of prospectors with propulsion capabilities. They will be the Arkyd 200 and 300 series. These will approach asteroids and analyze their composition.

After identifying the best candidates in terms of distance, speed, physical stability, and composition, they will launch the actual mining spacecraft.

Some of them may be swarms that will grab asteroids and bring them closer to Earth for mining. Others will be large containers that will engulf the asteroids to move them and process them."....

http://gizmodo.com/5905090/this-is-how-asteroid-mining-will-work

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#9
In reply to #8

Re: So You Want to Buy an Asteroid...

04/06/2013 9:52 PM

Sign me up! They are going to need a service tech!

Do they have stock available to buy yet?

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#10
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Re: So You Want to Buy an Asteroid...

04/07/2013 12:49 AM
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#14
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Re: So You Want to Buy an Asteroid...

04/08/2013 10:36 AM

<...billions of dollars worth of these metals...>

Earth dollars or Mars ones? And doesn't supply-and-demand work on asteroids as well? Just because some metal has been harnessed, doesn't mean that the money is there to buy it.

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#11

Re: So You Want to Buy an Asteroid...

04/07/2013 6:06 PM

Why leave it in orbit? May as well rock-bolt the worlds largest parachute to it, drag it into our upper atmosphere, let it fall gracefully to earth, and save an $11,000/pound trip later on.

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#12
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Re: So You Want to Buy an Asteroid...

04/07/2013 6:55 PM

I fail to follow (detect?) your logic.

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#13
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Re: So You Want to Buy an Asteroid...

04/07/2013 9:21 PM

Besides saving money on flying into space every time you wanted to mine/take samples etc. There really wasnt much logical thought process that went into my suggestion........Pretty normal for a Monday morning. :)

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#17
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Re: So You Want to Buy an Asteroid...

04/08/2013 2:07 PM

I say we land them in NK then have the SK crues process them then sell the raw material to china to build more cheap stuff for the rest of the world!

One stone four birds so to speak!

Relating to bringing one down on purpose once the asteroid has been brought into a stationary orbit its overall speed at which it would then impact the earth will be far far less than it would had it been going at the typical speeds most meteors enter the atmosphere.

Some where around 10 or so years ago I read a few theories on the concept where it was figured that by doing a controlled entry most metallic bodies would not exceed more than a few hundred MPH at best on impact even in a straight down trajectory from a stationary orbiting position.

The point is a 1000 ton metallic asteroid hitting the ground at 300 - 500 MPH packs far less punch than it hitting at 30,000 - 40,000 MPH.

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#15

Re: So You Want to Buy an Asteroid...

04/08/2013 10:42 AM

The exploration of space has created some great technology. I see mining could add some profit to it.

One problem! Along with profit comes free enterprise. Something government are not suppose to be into. Profit tends to lead to greed. Greed tends to lead to the desire of more profit. So someone cuts corners. Murphy comes along screws everything up. Now the towed asteroid say one the size the hit Russia recently. It's now on a course to hit a major metropolitan area.

That was a small asteroid.

What's is our response time to divert this disaster? What do we have in place to do it with?

I do understand this is a step at diverting those asteroids that in the future may pose a hazard. But to tow it back to earth orbit and possibly create one with out having other safe guards in place.

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#16

Re: So You Want to Buy an Asteroid...

04/08/2013 10:48 AM

Once upon a time I read about an idea for forming the mined materials into aerodynamic shapes using solar furnaces and a little compressed gas to foam the metals. I believe the idea allowed for a little material loss during deceleration into the atmosphere but when it landed in the ocean, it would float.

Sounded like a good idea if the metal could be foamed while it was being formed. A little air in a vacuum would make for some pretty good sized bubbles. No parachutes required this way!

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#19

Re: So You Want to Buy an Asteroid...

04/08/2013 2:21 PM

"...audacious..."

I'll say!

It took NASA 182 (Mars) days to finish up drilling this .63" diameter hole:

If someone is paying $$Trillions per ounce, we're in business!!!

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#20
In reply to #19

Re: So You Want to Buy an Asteroid...

04/08/2013 3:26 PM

Eerily similar to this giant eye found on the beach here....

But this is not a specialized vehicle for mining....either

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#21
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Re: So You Want to Buy an Asteroid...

04/08/2013 7:15 PM

Well the way I deal with these issues with customers is I tell them they can either pay me by the hour or by the job.

At that point I usually get asked, What's the difference?

I then say, Well with one I get done a lot quicker but either way your bill will be the same.

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#22

Re: So You Want to Buy an Asteroid...

04/18/2013 7:52 AM

Since when does anything done by Big Government become cost effective and safe? I can envision a major Clusterf$k by NASA that results in this space rock landing in our collective laps....

Just saying........not a good idea bringing it into Earth orbit!

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#23
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Re: So You Want to Buy an Asteroid...

04/20/2013 12:57 PM

These objects are much more hazardous if they are brought into our atmo, but most of the mass mined in space will stay there. Likely parking orbit for asteroids will be on the other side of the moon because lunar mining is also going to happen no matter what-and considering that our moon is already moving away from Earth, it makes good sense to add mass to it via lunar based manufacturing. They know the risk in bringing down a few microbes from space via a spacerock exists, so little will see planetside without having been fully sterilized. That means full processing beforehand is the only option. I'd guess offhand that there are going to be lots of huge gem and metal massifs that will eventually be brought down in their natural form just because we do like to collect that kind of stuff, but other than that, little will be coming down at the start for anything other than research.

Just keeping our lunar mass relationship stable will be a big chore as this heats up and people from all over the world are naturally wanting to get parking space for their rocks and lunar regolith is being converted and boosted to space as well as lunar manufacturing continually cycling mass. I see the mass relationship issue as the biggest thing on the list; both out at the Belt or Cloud as well as lunar and at the other planets/moons. We are in the shooting gallery already, and we should be keeping in mind that we are just at the start of it as we go forward in our attempt to correctly redistribute mass all over our solar system. NASA's got a real job of work there.

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#24
In reply to #23

Re: So You Want to Buy an Asteroid...

04/20/2013 8:43 PM

'....I see the mass relationship issue as the biggest thing on the list; both out at the Belt or Cloud as well as lunar and at the other planets/moons.....'

.

'The biggest thing on the list'? Really? Have you done much/any analysis of you specific concern?

.

Putting some numbers to it could be very informative....

.

Assuming that the mass were removed in directions with vectors that cancel, allowing you to just look at the loss of mass and not any action/reaction forces of the rockets, if a full 1% of the moons mass were suddenly to vanish from the moon.... How much do you thing the orbit of the moon would change?

.

I think your concern over this issue is misplaced.

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#25
In reply to #24

Re: So You Want to Buy an Asteroid...

04/23/2013 4:19 PM

Good. Nothing to worry about. And yeah, I do axxually read. And from what I can see, the propulsion methods and mechanical techniques are working themselves out, and will in fact allow for the first testbed craft to start heading out within something like their projections.

So if you don't mind, I'll go on with my delusion. A moon moving away from Earth. Earth gravitational field weak, field lines all erratic, polar destabilization. Heavy asteroids in our locale. Our position in the so called shooting gallery. Go ahead and argue fuel numbers from rote by kJ/mol or eV if you think that's what you need to think on, or maybe just stop yer crack from showing a sec. I done told you, dude. Your ego blows. If you think my point is without merit, fine. And just good luck to us. We've done this so many times, we ain't gonna screw this up. How bout you point me to the journal or paper that covers this reality, seeing as how it's not even an issue?

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#27
In reply to #25

Re: So You Want to Buy an Asteroid...

04/23/2013 8:03 PM

'....How bout you point me to the journal or paper that covers this reality, seeing as how it's not even an issue?....'

.

This isn't a groundbreaking or even very noteworthy discussion likely be covered in journals or papers (well at least those in this century).

Even if this wasn't old news, why would 'seeing as how its not even an issue', suggest that it should be readily found in professional journals or research papers?

.

Here is why you should not be concerned:

Let's consider orbital period, T.

T = 2Π√[(semi major axis of elliptical orbit)3 / ((mass of body being orbited +mass of the orbiting body)(gravitational constant))]

.

It should become readily apparent that nothing changes if mass is taken from the orbiting body and transferred to the body being orbited....since the sum of the two doesn't change.

.

But lets consider what happens if someone is mining the Moon and doesn't send the material to Earth. Lets say they are total rapscallions and they shoot the mined material to the Dog Star.

.

The mass of the Moon is roughly 1.2% of the mass of the Earth.

.

So if 1/12th of the mass of the Moon were removed and shot to the Dog Star the semi-major axis of the moons orbit would have to decrease to 3√[1-((1.012-1.011)/1.012)] % of the original...so 99.967% of the original for the original orbital period to remain unchanged (this is not what would occur, but gives you an idea of the magnitude of how small any change would be even for such a huge amount removed from the moon).

Alternately the Period could increase by √[1/(1-((1.012-1.011)/1.012))] ....or to roughly 1.0004944 % and have the major axis of the elliptical orbit remain the same.

.

Bottom line: No one is going to remove 1/12th of the Moon and ship it to the Dog Star anytime soon, and even if they did, it won't have an Earth shattering effect.

The moon certainly wouldn't reach escape velocity or anything like that.

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#26

Re: So You Want to Buy an Asteroid...

04/23/2013 8:00 PM

Knowing what we do about our decreasing lunar proximity, is there a way to project what distance it will be when it starts rotating?

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#28
In reply to #26

Re: So You Want to Buy an Asteroid...

04/23/2013 8:25 PM

Too late. It 'started' rotating a long, long time ago.

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#29
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Re: So You Want to Buy an Asteroid...

04/23/2013 9:01 PM

Of course, but in relation to our weakening field, there has to be some spin increase based on that as well as the distance issue. So if we are looking at something like 4-5 solar cycles from now when asteroids start arriving; is there an existing orbital insertion solution for our planet/lunar differential? You see where I'm going, right? It just keeps getting more problematic for me at this point. I get that our people and our systems can do this as long as the system isn't changing much. But that's not us. Won't be for some time. Like your analogy about 1-12th the lunar mass, even if our poles were stabilized today, the fact that currently our moon is moving away today would still be a major factor in 44 or 55 years. Of course, we could just go after mining more than 1-12th of the moon real quick in the meantime, but I'm thinking more about the potential for a solution from math-but I don't know how to approach the combined distance, adding rotation, decreasing field issues in relation to some future actual solution that also then adds asteroids to the rest successfully-which I sort of want to define as returning our moon while not beaning us with anything.

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#30
In reply to #29

Re: So You Want to Buy an Asteroid...

04/24/2013 12:28 AM

The moon moving away (and at other times moving closer) is not a new phenomena. It isn't something you should invest much time worrying about....

The moon is currently moving away from the earth on average a little under 4 cm. per year.. Previously it was moving away from us at a higher rate, but it has gradually slowed and continues to slow its distancing.

Eventually, it will reverse and begin getting closer on average. It will continue until it is close enough for the cause of this phenomena to transfer enough angular momentum from the earth to the moon so that the moon begins once again to move (on average) away from the earth.

The process involves the tides and the spin of the earth. The moon pulls the tides making high spots on the earth....but the earth is also spinning, so these high spots are dragged off center. This off center mass pulls the moon in its direction and eventually causes the moon to speed up slightly....so on and so forth.

.

Also, no reason to sweat the disorderly magnetic poles. No reason to fear the coming pole reversal. This has all happened many many times in the past.

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#31
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Re: So You Want to Buy an Asteroid...

04/24/2013 10:43 AM

Eventually, it will reverse and begin getting closer on average.

I have never heard this before. Can you provide a link?

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#32
In reply to #31

Re: So You Want to Buy an Asteroid...

04/24/2013 8:13 PM

So looking for a link, it has become clear that I remember this incorrectly. It looks like the sun will expand and consume the planet before there has been enough time for a reversal to occur.

Good catch. Thanks for keeping me from disseminating bad info, and thanks for the opportunity to upgrade my understanding/recollection.

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#33
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Re: So You Want to Buy an Asteroid...

04/25/2013 12:43 AM

From when our pole went off axis, till now, has been a pretty short time. With the guesstimates about when the poles will stabilize being varied, we could be looking at that event right when an asteroid is being brought in. I hope they enforce some catch and release contingency regulations to start.

So the moon has slowed down in spite of our weakened field? Hadn't heard that one yet. That helps. Same scenario though, where we really don't know this process in action. While as you say, our planet and moon have done this dance many times, we can hardly count on it not to keep going till out of geolock in our current scenario, right? I'm gonna go digging around some on it, but I'll pop back to check for a reply. It might be that the moon couldn't get loose enough to clear geolock just due to our mass, at least not without help.

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#34
In reply to #33

Re: So You Want to Buy an Asteroid...

04/25/2013 2:13 AM

Wait. Are you concerned about the moon and the asteroid trajectories being affected by the Earth's wandering poles of its magnetic field?

.

The orbits of the moon and any asteroids are hardly affected to any significant degree by the magnetic field.

.

Oh and just to be clear, energy is being transferred to the moon from Earth, It is not 'slowing down'.

.

I am also a bit fuzzy on what you mean when you say it has been fairly recent since the pole went off axis.

Could you elaborate on how recently you think it occurred and exactly where 'on axis' was when the pole was located there?

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#35
In reply to #33

Re: So You Want to Buy an Asteroid...

04/25/2013 11:44 AM

Umm...I may be inferring here, but what do you think the earth's magnetic field has to do with the orbit of the moon?

Is there a suggestion here that the moon is held in orbit by the earth's magnetic field?

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#36
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Re: So You Want to Buy an Asteroid...

04/28/2013 5:30 PM

Sorry to make you people wait for my reply. Hospital time. Anyway. So I find that the sun actually puts twice the force on the moon that Earth does.-(NASA) Using that info, it stands to reason that our solar peak is canceling our current low field scenario vis a vis decreasing rate away from Earth. Further, that TISNAC is likely right that a given asteroid would pose little risk to our world other than stray chunks getting away from the mining containment, because toward sun would be an easier trip for the 'stroid to make. Thanks for helping me find a way to make better sense of the overall project, people. Of course, we still have a lot of unknowns about this pole shift of roughly the last decade because the south pole was stronger, so if as they think, the poles switch, then our planetary metals will either be aligned in a weaker overall pattern, or perhaps much stronger. I'm going to keep digging around on this, just because this is actually going to be a whole new technological world for us, and if I can find what specific places they have in mind-it should be a possibility to see exactly what they-NASA, etc; really expect us to end up with for a planetary field. And it's more interesting than planning a new neighborhood from a USGS hub.

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#37
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Re: So You Want to Buy an Asteroid...

04/28/2013 9:16 PM

I'm glad something in what I wrote was helpful.

I would like to clarify that I wasn't specifying that asteroid impacts with earth were of no danger....

Also, i think as far as gravity goes, for the moon, the force from the earth is larger than the force from the sun. This is supported by the much greater curvature of the path around the earth as compared to the path around the sun.

.

Also, I still can't tell if you are suggesting that the magnetic field of the earth has an appreciable effect on orbit of satellites, like the moon. Just to be clear, it does not.

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#38
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Re: So You Want to Buy an Asteroid...

04/29/2013 5:35 PM

I double checked the info from the NASA site and the primary link they provided for the sun providing twice the force on the moon that Earth does is at the 'cornucopia of cosmic rays' Q+A faq that I reached through NASA.gov.

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#39
In reply to #38

Re: So You Want to Buy an Asteroid...

05/03/2013 1:02 PM

That doesn't seem right. If there was any significant effect then we would weigh less in the daytime than we do at night.

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#42
In reply to #39

Re: So You Want to Buy an Asteroid...

05/04/2013 6:07 PM

While the distance from the moon to the center of the sun is ~392 times the distance from the moon to the center of the earth;

the distance from the surface of the earth to the center of the sun is 23,500 times the distance from the surface of the earth to the center of the sun.

.

The Sun is 330,000 times more massive than the Earth.

.

We can calculate the effect of the Sun's gravity on the surface of the Earth in relation to the Earth's gravity at its surface:

.

1g x 330,000/ (23,5002 ) ≈ 0.00054g

.

So at most the effect would be very very small. I think though since we are essentially in free fall in orbit, that there wouldn't be a measurable difference.

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#41
In reply to #38

Re: So You Want to Buy an Asteroid...

05/04/2013 4:50 PM

So after doing some quick calculations (I couldn't find the page you reference... a link would have been helpful), it looks like you are right. As counter-intuitive as it is, the Sun's gravity is a greater force on the Moon than the Earth's gravity is on the moon.

I checked with the following assumptions.

.

1. The Sun is ~330,000 more massive than the Earth, but its center is ~392 times more distant from the moon than the center of the earth.

.

300,000/(3922 ) ≈ 1.9

... so roughly twice the gravitational acceleration from the Sun than the Earth.

.

.

I stand corrected.

.

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#43
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Re: So You Want to Buy an Asteroid...

05/04/2013 6:23 PM

Well then corrected we both are, and far worse possibly. See, that 'commonly asked questions' faq at NASA gave me the impression that the knowledge was so rudimentary that I must have been walking in a real daze all my life. It was definitely aimed at kids and the ones that drop in with no knowledge regarding astrophysics at all. Be glad you didn't see it. You'd likely have felt like I did at the time.

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#44
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Re: So You Want to Buy an Asteroid...

05/05/2013 2:11 AM

SI Units

F=G*M0*M1/r^2

G=6.67384E-11

Sun - Earth r = 150 E9 :r^2 = 2.25 E22

Earth - Moon r = 384 E6 : r^2 = 1.4745 E17

Sun Mass = 1.989 E30

Earth Mass = 5.9723 E24

Moon Mass = 7.3477 E22

Earth+Moon Mass = 6.0578 E24

Gravitational Force Sun - Earth

6.67384 E-11 * 1.989E30 * 5.97219E24 / 2.25E22 = 3.5234 E22

Gravitational Force Earth - Moon

6.67384 E-11 * 5.97219 E24 * 7.3477 E22 / 1.4745 E17 = 1.9862 E20

Gravitational Force Sun - Moon

G=6.67384E-11 * 1.989 E30 * 7.3477 E22 / 2.25 E22 = 4.3349 E20

Gravitational Force Sun - (Earth+Moon)

G=6.67384E-11 * 1.989E30 * 6.0578 E24 / 2.25 E22 = 3.5739 E22

Centripetal Force = m V^2/r

Orbital Speed = 29.8 km/s = 29,800 m/s : V^2 = 888040000

R= 150 E9 m

M =6.0578 E24 kg

6.0578 E 24 * 888040000 / 150 E9 = 3.5864 E22

Close enough to say mv^2/r = GMm/r^2

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#45
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Re: So You Want to Buy an Asteroid...

05/05/2013 7:01 AM

So much data.

So little communicated.

What point(s) were you trying to make?.... (perhaps in a sentence this time)

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#46
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Re: So You Want to Buy an Asteroid...

05/05/2013 3:03 PM

Hopefully you are not asking for complete and properly structured sentences.

I was just doing a little verification on what was posted earlier.

The ratio of Sun-Moon Gforce to Earth - Moon Gforce using classical physics is 2.1825.

How does the moon stay in earth orbit with the Sun Gforce over 2 times that of that imparted by the Earth?

Is it because the orbital plane of the moon around the earth is nearly the same as that of the earth around the Sun; where the Sun Moon G Force * displacement cancel throughout a complete orbital period of the moon about the Earth? Intuition tells me that if the moon orbited in any other plane it wouldn't be here. The same could be said for the moons of all of the other planets.

The relationship of Centripetal Force to Gravitational Force was just a cross-check of classical physical equation. Which didn't cross reference with the equation for escape velocity.

When I went to bed I did a little equality exercise and solved for V. That V=Sqrt (U/r) where U is the Gravitational Parameter, r is the orbital radius, and V is orbital speed in a closed stable circular orbit. Granted orbits aren't circular; but I was just curious.

This doesn't square with the equation for escape velocity which is V= sqrt(2U/r).

I don't know where I screwed up - I'll figure it out in time. It will give me some incentive to review some freshman physics that I haven't reviewed for awhile. Including Kepler's second and third law.

I also found that my BASIC Interpreter gives overflow errors when solving for planetary Gforce; probably because of the processor in my little Netbook I use; but its something I now know to watch out for. That in itself was worth the exercise.

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#47
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Re: So You Want to Buy an Asteroid...

05/05/2013 7:06 PM

Okay. Thank you.

.

I think the reason the Moon and Earth aren't pried apart by Sun's gravity is that both are in free fall around the Sun. The Sun is pulling on the Earth in the same way it is pulling on the Moon and in free fall the acceleration isn't noticeable.

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#40

Re: So You Want to Buy an Asteroid...

05/04/2013 1:55 AM

Using the basic rocket equation has anyone calculated the amount of fuel a Newtonian Propulsion Method would require to impart even a very small delta V to a relatively small metallic asteroid?

Are we sure this isn't sky pie?

Since semi-major axis defines specific orbital energy; it shouldn't take a Rocket Scientist to estimate the delta V required to capture a passing asteroid in the Moon/Earth system. But I think what you are going to find; unless you can find a very convenient asteroid with about the same semi-major axis as the Earth/Moon system; its going to take a HUGE amount of fuel mass.

I suppose it might be possible to use an energetic impulse maneuver to perhaps alter eccentricity enough to position for a gravity assist maneuver; but whats being discussed here isn't a tug boat and a barge. The conditions would have to be so serendipitous as to be considered a "gift from God." And the energies we are dealing with are so large that any Newtonian Propulsion Method is probably out of the question.

Ohh - and screw up - just a little bit - and very bad things can happen.

Is it probable an impact of a metallic asteroid of about 100 meters in diameter would not be measured in megaton equivalent - it would be measured in HUNDREDS of megaton equivalent. Possibly, after Mother Earth added resulting geologic input - like - uhhh - no food crops for a couple of years type event.

Personally I would be trying to figure out a REALISTIC and CALCULABLE method of imparting the minuscule delta V required to avoid an impact - that is - if you see it coming far enough in advance.

Planned and Executable Orbital Capture of a sizable metallic asteroid? It might be tasty ski pie; but its still sky pie.

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