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danielravennest t1_j65aq9k wrote

Aside from collectibles and science, the point of asteroid mining isn't to bring stuff back to Earth. It is to replace the high cost of launching stuff from Earth.

Let's say the Starship rocket works as intended and can fly for $20 million a launch. It takes about five tanker flights plus the cargo launch to get ~120 tons to the Moon's neighborhood. So $120 million for 120 tons is $1 million per ton. If you can mine usable products from asteroids for less than this, you come out ahead.

Metallic asteroids contain about 15-50 parts per million of the "Platinum group metals" (the ones below iron, cobalt, and nickel on the Periodic Table). Parts per million is the same as grams per ton, so 15-50 grams per ton. Average PGM price is around $50/gram, so market value is $750-2500/ton.

They are alloyed with the three base metals as ~90% iron, 1% cobalt, and 9% nickel (the proportions vary by sample). So first, you have to extract the PGMs from a chunk of iron alloy, and second a little added carbon turns the iron alloy into a decent steel alloy. There are other asteroid types (the carbonaceous ones) with carbon, so that's not hard.

Now your ton of metallic asteroid is worth $1 million for structural steel in space, because that's the launch cost you avoid for not launching structural parts from Earth. The value as structural metal is worth way way more than the small amount of precious metals in it.

You can try to separate out the PGMs before leaving the asteroid, or afterwards so you can use both the iron alloy and the PGMs, but I highly doubt you can process it in space for the $750-2500/ton market value. For comparison, the price of hot-rolled ordinary steel on Earth is $775/ton right now.

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SailingNaked t1_j65dsfv wrote

Great explanation, but with an oligopsony market, is that structural steel really worth $1m/ton?

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danielravennest t1_j65fya5 wrote

NASA is like 1/16th of the space market. It is much more diverse than most people realize, and most of it is services, not launch and building satellites.

I used the steel as an example, because it is the same place you would extract the Platinum Group Metals. The first space-mined products are likely to be (a) bulk rock for shielding, and (b) water and carbon compounds for propellants and life support.

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SailingNaked t1_j65hx8p wrote

I agree.

My question was more of the economics of leaving the market in space instead of back to earth. There are very few buyers that have the capabilities of using material produced in space, and none of them have anything in space currently that can utilize that material.

If you make structural steel in space, you can't price it at what it would cost to send it up. There's no manufacturing in space yet. You'd have to price it below what it would cost to send up and build said manufacturing capabilities than it would just sending up the finished product.

The issue still remains, the only profitable market is on earth... for now.

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danielravennest t1_j68ueh8 wrote

> There are very few buyers that have the capabilities of using material produced in space, ... There's no manufacturing in space yet. ... build said manufacturing capabilities

Well, I'm working on that. Check the "view history" tab on any page of that book to see who wrote it.

All your words that I quoted above are correct. Aside from robot arms and a 3D printer on the ISS, there is essentially no industrial capacity in space yet. Factories of the kind we build on Earth are too heavy to launch into space. So how do you get started?

A "seed factory", as I describe in that unfinished book, is a starter set of machines and tools that are used to make more machines to expand itself. This is where asteroid metal and carbon come in. Iron is by far the most important industrial metal, and 98% goes into making steel (iron with added carbon). Metallic asteroids are already in native form. They don't have to have the oxygen removed like iron ore on Earth.

The added machines are first to increase scale from the starter set, and second to make machines that work with other materials (glass, aluminum, etc.). You will still have to deliver some materials and parts from Earth while you bootstrap, but a lot less than if you tried to bring everything from Earth.

The starter machines can be as light as 20 kg, so certainly a single 100 ton Starship payload should be able to deliver a functioning machine shop with usable capacity.

You wouldn't jump into this without doing some R&D. We need to fly some asteroid retrieval missions in the ton rather than ~1 kg range coming back on the Osiris-REX mission. Ideally you want several different asteroid type samples. Then you feed those materials into pilot-scale processing machines and figure out what works and what doesn't.

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