Asteroid/Near Earth object mining

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  • #126
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The gases would be liquified. Not trivial to keep the depot cold enough, but possible.
 
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The gases would be liquified. Not trivial to keep the depot cold enough, but possible.
Parking the depot in a stable orbit that could keep it in the lunar shadow would be a good start.
 
  • #128
Parking the depot in a stable orbit that could keep it in the lunar shadow would be a good start.
Are there any such stable orbits? The only one I can think of would be an elliptic orbit, passing between the moon and Earth when the moon is nearer the sun and out beyond the moon on the other side, but I imagine that would have a slower period than the moons' orbit so wouldn't work anyway? I expect a large shield would achieve the same effect though.
 
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There is no such orbit. Relevance for LEO/GEO missions means the orbital period has to be a day or shorter and the satellite has to be close to Earth - the moon won't be between Earth and sun for most of its time, and even when it is, the satellite would pass through the shadow quickly.

JWST has passive cooling down to 50 K, better than what is needed for hydrogen/oxygen depots, and some active cooling would be possible as well (unlike the JWST, the depot is not that sensitive to vibrations and smaller changes in the thermal environment).
 
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I expect a large shield would achieve the same effect though.
Good point.
 
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There is no such orbit. Relevance for LEO/GEO missions means the orbital period has to be a day or shorter and the satellite has to be close to Earth - the moon won't be between Earth and sun for most of its time, and even when it is, the satellite would pass through the shadow quickly.

JWST has passive cooling down to 50 K, better than what is needed for hydrogen/oxygen depots, and some active cooling would be possible as well (unlike the JWST, the depot is not that sensitive to vibrations and smaller changes in the thermal environment).
Some info here. http://webbtelescope.org/article/Technology_at_the_Extremes/8
 
  • #134
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101955 Bennu is a near Earth asteroid, and quite a prominent one: it has a 0.04% probability to hit Earth in the 22nd century, and 10% chance to hit it within the next millions of years.

As comparison: an impact of an asteroid as large as Bennu happens on average every ~100,000 years, which corresponds to a 0.1% chance of such an impact per century.

It was chosen as target for the mission because it is easy to access and because a better understanding of it helps to predict its future orbit and also future orbits of similar objects.
 
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The Osiris mission is intended to return small samples to Earth, so it is mining in a sense, although on a tiny scale.
If successful those samples could be very valuable in terms of the scientific reward, we will know lot more about the very early solar system.
However the material is unlikely to contain substances which would have much value if discovered on Earth.
Most asteroids are either Nickel-Iron or are a mixture of metal oxides (rock), Carbon is also commonly present.
 
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  • #137
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Please do not copy large amounts of text like this, that can give copyright issues. I removed the quotes, they are accessible at the linked website.
The Near Earth Asteroids (NEAs) alone contain enough of every element to support an affluent and fully recycling population of 500 billion people.
So do the uppermost meters of Earth's crust.
A cubic kilometer of randomly assembled material on Earth has gold with a market value of $1 billion. It is not about the elements being present - it is about having them in useful form.
 
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Please do not copy large amounts of text like this, that can give copyright issues.
understood
 
  • #140
sophiecentaur
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Here's a question about best use of energy resources. Is it better to grab an asteroid and bring it into a convenient orbit or to chase on it and land (robots of course) and extract the useful material first - then bring the stuff back to Earth, leaving the remaining lump to carry on its way (course adjusted so it will never come near Earth? It would depend on the proportion of the asteroid mass that would be useful. I have very little idea of the energy sums involved and the timescale involved but almost any plan would take some time (years?) to execute, I suppose.
I can't help thinking that there must be terrestrial resources that would be more attainable and cheaper - they clearly haven't all be found yet and I think that's obvious, when you consider the "10year limit" that's been how long oil resources would last over the sixty years that have passed since I first was told that figure..
 
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You would like the resource site to come close (in orbital mechanical terms) to Earth bur the rest would depend on too many unknown factors to determine using known and predicted factors.
 
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101955 Bennu is a near Earth asteroid, and quite a prominent one: it has a 0.04% probability to hit Earth in the 22nd century, and 10% chance to hit it within the next millions of years.

As comparison: an impact of an asteroid as large as Bennu happens on average every ~100,000 years, which corresponds to a 0.1% chance of such an impact per century.

It was chosen as target for the mission because it is easy to access and because a better understanding of it helps to predict its future orbit and also future orbits of similar objects.
Is it alright to ask a question and provide a possible if highly hypothetical speculative suggestion?

I understand that Bennu is. Spinning up. And spewing out particles.

Spinning up tells me the object is gravitationally differentiating. With higher density material, sinking towards the center. Pushing lower density material towards the surface.

If so that would release gravitational potential energy. Could that be the source of energy underlying? The particle ejections?
 
  • #143
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Spinning up tells me the object is gravitationally differentiating. With higher density material, sinking towards the center. Pushing lower density material towards the surface.
The claim in Wiki is different.

https://en.wikipedia.org/wiki/101955_Bennu

"Due to the uneven emission of thermal radiation from its surface as Bennu rotates in sunlight, the rotation period of Bennu decreases by about one second every 100 years"

The listed reference for that claim is https://www.asteroidmission.org/?latest-news=nasa-mission-reveals-asteroid-big-surprises
 
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  • #144
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Spinning up tells me the object is gravitationally differentiating.
No, it is many orders of magnitude too small for that.
Interactions with the Sun are important for objects that size, just as in this case.
 
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