There's a reason that most meteors that enter the Earth's atmosphere explode before reaching the surface.
I think it is also worth investigating methods to bring high value raw material to the earths surface that are more brutish, yet possible more economical & within existing technological capability.Here is my proposal:1. Baseline mass return is around 1000ton or less, which is in the ballpark of the Asteroid redirect mission profile.2. Space mining will focus on precious metal initially. Returning low value metals like nickel & iron just may never be worth it, & they are probably worth more to use in space for building structures. This example will use platinum.3. I think in space refining will need to separate the Pt from the bulk of the asteroid material. This is where the majority of operational cost will be.4. Once separated & refined, it will be melted & formed into a slug/projectile. Some Ni/Fe may be utilized as sacrificial material on the blunt end, & as a casing for the Pt that will undergo entry heating as it encounters earths atmosphere. 5. A 1000 ton slug of Pt would be around 4.46 meter in diameter, if it was made spherical. Ideally I would make it cylindrical, with a Ni-Fe blunted nose. The value of the Pt metal is around $31 Billion USD ( around 7-8 years of annual planetary consumption of Pt ) 6. Precision crash land it somewhere in the arctic ocean, where ocean depth is around 1000m, but basically within the capability for robotic retrieval equipment.An object of this size entering the earths atmosphere at a 45 degree angle at 20 kps would likely survive entirely intact on the seafloor. ( I entered the parameters in this interesting model ) You could also separate the 1000 tons into multiple projectiles to customize the impact events to minimize material loss and environmental impact.http://impact.ese.ic.ac.uk/ImpactEffects/So for $31 Billion USD sitting at a well defined location on the seafloor: A. Can technology be made to retrieve the metals for circulation into global Pt demand and still make money?B. Can a space mining company make and acceptable environmental impact arguments of conducting sub megaton impact events in an ocean vs. the impact of conventional mining?Seems plausible to me.
6. Precision crash land it somewhere in the arctic ocean, where ocean depth is around 1000m, but basically within the capability for robotic retrieval equipment.
www.sciencealert.com/a-new-type-of-artificial-photosynthesis-cleans-the-air-and-produces-energy#.WSmDe3F2xeg.linkPlease read all of it . Cheers Floss
Quote from: Stan-1967 on 05/27/2017 01:36 am6. Precision crash land it somewhere in the arctic ocean, where ocean depth is around 1000m, but basically within the capability for robotic retrieval equipment.Why an ocean impact?
If you want something that works physics-wise, don't use JP Aerospace as your inspiration.
Quote from: Paul451 on 05/27/2017 10:48 amQuote from: Stan-1967 on 05/27/2017 01:36 am6. Precision crash land it somewhere in the arctic ocean, where ocean depth is around 1000m, but basically within the capability for robotic retrieval equipment.Why an ocean impact?When the projectile lands, there is still around 90% of the kinetic energy left,
Quote from: Stan-1967 on 05/27/2017 02:14 pmQuote from: Paul451 on 05/27/2017 10:48 amQuote from: Stan-1967 on 05/27/2017 01:36 am6. Precision crash land it somewhere in the arctic ocean, where ocean depth is around 1000m, but basically within the capability for robotic retrieval equipment.Why an ocean impact?When the projectile lands, there is still around 90% of the kinetic energy left,How do you come to that conclusion? That re-entry only reduces velocity by 6 percent?
I would suggest that by the time it is economical to refine platinum from asteroids we'll have large scale, reusable craft flying frequently between the Earth's surface and space. Think ITS flying weekly, at least. At that point, returning the platinum to the surface of the Earth is a non-issue -- we'll just carry it down on the ITS-scale ships that are flying regularly anyway. That will be cheaper than building some kind of heat shield around a giant slug of platinum then dredging it up from the bottom of a lake.
Quote from: ChrisWilson68 on 05/28/2017 07:30 amI would suggest that by the time it is economical to refine platinum from asteroids we'll have large scale, reusable craft flying frequently between the Earth's surface and space. Think ITS flying weekly, at least. At that point, returning the platinum to the surface of the Earth is a non-issue -- we'll just carry it down on the ITS-scale ships that are flying regularly anyway. That will be cheaper than building some kind of heat shield around a giant slug of platinum then dredging it up from the bottom of a lake.Are you suggesting that ITS scale ships will match the orbit of asteroid ore shipments, or all ore shipments will be have to be placed into an earth orbit for pickup by a ITS ship?
Sounds expensive in DV and propulsion hardware cycles. There's a lot of hand waving in that scenario.It's also dismissive & unfounded to automatically assign high technical hurdles to something unknown.
The "heat shield" could end up being incredibly simple if made of sacrificial nickel:iron.
Assuming high complexity
reminds me of when SpaceX signaled their intention to land rockets downrange at sea. Speculators were suggesting Musk should buy the SeaLaunch platform, or procure a decommissioned aircraft carrier, & other complicated bunk. What happened? He bought a cheap barge and welded some plate steel to the deck.
... I'm more interested in how to extract & concentrate the metal, as well as ideas how to capture market share without crashing global prices.
The global annual supply of PGMs is worth around ~$12 billion at current prices, for roughly 500 tons of refined material ( palladium + platinum being around 45% + 45% of it ).Nearly 70% of the total supply goes to automotive catalysts, with jewelry grabbing a second good slice.
Quote from: Stan-1967 on 05/29/2017 03:43 pm... I'm more interested in how to extract & concentrate the metal, as well as ideas how to capture market share without crashing global prices. edited & snipped...I think there are two possible models of development: aim to supply maybe 10-20% of the annual market, effectively creating another significant supply region besides South Africa and Russia, with the corresponding price drop. Still serving existing markets. It's tough to come up with feasible numbers for developing such a venture and seeing returns on a reasonable timescale.Or, aim to increase the supply by some insane amount, like 5x current actual demand, crash prices and expect new demand and applications to emerge. They would have to be new, as there is simply no way jewelry and diesel engine catalysts will soak up that much even at drastically lower material prices. Unless such a new application is identified/mapped out, nobody will invest in this venture due to massive capital investment at insanely high risk.Which i think basically comes back to - should space PGMs mining ever be developed, it won't be purely market driven, it'll need significant upfront public investment for R&D and risk reduction of related technologies. Most likely this investment can come from countries that are either resource scarce or see it as strategic value. China, maybe.