Starship Asterisk*

[quote="Chris Peterson" post_id=285192 time=1534951363 user_id=117706]Now, now. Don't exaggerate. If you're careful, you can probably recover 5% of the material. (And a lot more if you return it in a re-entry container, but that might add a lot of expense.)[/quote]
I wasn't talking about the mass of material. But the cost & value of it. The ratio of $/kg for mass in orbit vs $/kg of raw ore shows that basically all the value is in its kinetic energy and the fact it is in orbit, not its mundane metal content.

[img3=""]https://pbs.twimg.com/media/DlX0xVfWwAAyVH2.jpg[/img3]

[quote=BDanielMayfield post_id=285200 time=1534981659 user_id=139536]
Wouldn't mining the Moon be less expensive than mining asteroids? It's been collecting ground up asteroid material all over it's surface for 4 billion years, it's always just over there, and there's no chance of it hitting us if something goes wrong.
[/quote]

As a rule, the more diffuse and mixed the ore, the more expensive it is to obtain the desired elements. It may be a problem for many asteroids that there are fewer mechanisms to concentrate elements and minerals. But getting stuff from moondust is about the same problem as getting it from our own oceans (which have pretty much everything dissolved in them, e.g. 10 g/km[sup]3[/sup] gold in seawater).

Wouldn't mining the Moon be less expensive than mining asteroids? It's been collecting ground up asteroid material all over it's surface for 4 billion years, it's always just over there, and there's no chance of it hitting us if something goes wrong.

Bruce

[float=left][youtube]https://www.youtube.com/watch?v=9LzZ1ORjSjk[/youtube][/float][quote=bls0326 post_id=285195 time=1534968545 user_id=140793]

Just semantics, but it seems odd to say the Hayabusa2 is hovering when it has an orbital speed of something like 60,000 mph.
More like it is orbiting (flying?) in formation with Ryugu.[/quote][quote=" https://www.etymonline.com/word/hover#etymonline_v_14510"]

hover (v.) c. 1400, hoveren, frequentative of hoven "hover, tarry, linger;" see hove (v.1). As a noun from 1510s.

hove (v.1) mid-13c., of birds, "remain suspended in air;" also generally, "to float, rise to the surface;" from c. 1300 as "wait in readiness or expectation;" late 14c. as "loom protectively over," also figurative, of unknown origin. In Middle English often of ships at anchor, standing off a coast. Common 13c.-16c., then superseded by its derivative, hover (v.).[/quote]

Just semantics, but it seems odd to say the Hayabusa2 is hovering when it has an orbital speed of something like 60,000 mph. More like it is orbiting (flying?) in formation with Ryugu.

[quote=isoparix post_id=285190 time=1534950882]

Are the masses of Hayabusa2 and Ryugu too small to allow H2 to be in an orbit of its target?
Or is the probe just coasting/manoeuvring alongside, with both in orbit around the sun?[/quote]
A close orbit around any solid body generally takes around 2 or 3 hours.

That amounts to Ryugu orbital & escape velocities on the order of ~1 km/hr.

With such low velocities to deal with it takes little effort for Hayabusa2 to safely hover above
[b][u]a Ryugu in full solar illumination[/u][/b] and not bother to reorient either H2's cameras or solar panels.

https://www.syfy.com/syfywire/mea-culpa-circling-ryugu

[quote=heehaw post_id=285178 time=1534928778]
People babble about mining asteroids, but I don't see how it could possibly be cost-effective. Could it be?
[/quote]
Figuring out the value of asteroidal materials to Earth-based industries is not likely to strongly suggest profit. Asteroid mining will be useful and profitable (if anyone cares) when a significant number of us have reason to live and work in space.

Rob

[quote=suicidejunkie post_id=285189 time=1534950344 user_id=143121]
If you're thinking about selling asteroid ore on earth, don't bother.
Those reentry flames won't just be burning off the ablator, they'll be burning off 99.99% of the intrinsic value (the kinetic energy!) of your materials.
[/quote]

Now, now. Don't exaggerate. If you're careful, you can probably recover 5% of the material. (And a lot more if you return it in a re-entry container, but that might add a lot of expense.)

(An orbit of any reasonable period, that is!)

Are the masses of Hayabusa2 and Ryugu too small to allow H2 to be in an orbit of its target? Or is the probe just coasting/manoeuvring alongside, with both in orbit around the sun?

If you just want to have some mined elements on paper, it will not be cost effective.

If you want to have some materials specifically in space for some purpose, nature is giving you a $2000 to $20000 per kg subsidy from the fact that the asteroid is already in space. That's what will drive it to be cost effective. You don't have to mine asteroids cheaper than mining on earth. You just have to mine asteroids cheaper than building rockets to throw ore into space.

If you're thinking about selling asteroid ore on earth, don't bother.
Those reentry flames won't just be burning off the ablator, they'll be burning off 99.99% of the intrinsic value (the kinetic energy!) of your materials.

[quote=heehaw post_id=285178 time=1534928778]
People babble about mining asteroids, but I don't see how it could possibly be cost-effective. Could it be?
[/quote]

It probably could be if we focused on rare earths and other intrinsically valuable elements, and developed the technology to extract and refine it in place robotically. I don't see it being cost effective at any time in the next few decades, possibly longer.

Nickel-iron meteorites contain Cobalt, Germanium, Gallium and Iridium. If those could be extracted on site, then an asteoid source might be more viable.
JOhn

People babble about mining asteroids, but I don't see how it could possibly be cost-effective. Could it be?

[url=https://apod.nasa.gov/apod/ap180822.html] [img]https://apod.nasa.gov/apod/calendar/S_180822.jpg[/img] [size=150]Asteroid Ryugu from Hayabusa2[/size][/url]

[b] Explanation: [/b] This big space diamond has an [url=http://www.asterank.com/]estimated value[/url] of over 80 billion dollars. It's only diamond in shape, though -- [url=https://en.wikipedia.org/wiki/162173_Ryugu]asteroid 162173 Ryugu[/url] is thought to be composed of mostly [url=https://en.wikipedia.org/wiki/Nickel]nickel[/url] and [url=https://periodic.lanl.gov/26.shtml]iron[/url]. Asteroids like [url=https://solarsystem.nasa.gov/missions/hayabusa-2/in-depth/]Ryugu[/url] are interesting for several reasons, perhaps foremost because they are near the Earth and might, one day in the far future, pose an [url=https://sservi.nasa.gov/articles/neoshield-protecting-earth-impact-threats/]impact threat[/url]. In the nearer term, [url=http://www.planetary.org/blogs/jason-davis/new-global-views-ryugu-20km.html]Ryugu[/url] is interesting because it may be possible to send future spacecraft there to [url=http://theconversation.com/mining-asteroids-could-unlock-untold-wealth-heres-how-to-get-started-95675]mine it[/url], thus providing humanity with a [url=https://en.wikipedia.org/wiki/Asteroid_mining]new source[/url] of valuable metals. Scientifically, [url=http://www.planetary.org/multimedia/space-images/?keywords=hayabusa-2]Ryugu[/url] is interesting because it carries information about how our Solar System formed billions of years ago, and why its orbit takes it [url=https://cneos.jpl.nasa.gov/ca/intro.html]so close[/url] to Earth. [url=https://en.wikipedia.org/wiki/Japan]Japan[/url]'s robotic [url=https://en.wikipedia.org/wiki/Hayabusa2]spacecraft Hayabusa2[/url] just [url=https://apod.nasa.gov/apod/ap180625.html]arrived[/url] at this one-kilometer wide asteroid in late June. The [url=http://www.hayabusa2.jaxa.jp/topics/20180725je/index_e.html]featured image[/url] shows surface structures unknown before spacecraft Hayabusa2's arrival, including rock fields and craters. Within the next three months, [url=http://www.planetary.org/blogs/emily-lakdawalla/2018/0525-keep-up-with-hayabusa2.html]Hayabusa2 is scheduled[/url] to unleash several probes, some that will land on Ryugu and hop around, while Hayabusa2 itself will mine just a little bit of the [url=https://solarsystem.nasa.gov/small-bodies/asteroids/in-depth/]asteroid[/url] for [url=https://apod.nasa.gov/apod/ap090705.html]return to Earth[/url].


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