23 thoughts on “There’s Gold In Them Thar Asteroids”

  1. Rand,

    Wondering about Zimmerman’s math here:

    “…Consider this: A single Starship has the potential to return as much as a 100 tons from orbit.…”

    We know the current design spec for Super Heavy + Starship is max payload to LEO ≈ 100 mt. Am I in error, or…is it not the same Δenergy to return the same mass, and even given that reentry dissipates bunches of Δ via aerobraking, does a fully (on-orbit-re-)fueled Starship (sans Super Heavy) have enough Δv then to land 100 mt? (My knee-jerk reaction says no, but I’d love to be shown to be in error 😊.)

    Just askin…!


  2. Almost all of the energy for landing is dissipated during reentry. It will have lost almost all horizontal kinetic energy by the time it reaches the top of the troposphere, then fall straight down and make its propulsive landing from terminal velocity, which is fairly low. Note, it is not fully fueled at entry for landing, only the header tanks are full. Right now, the Starship payload is up in the air. The guesstimate is up to 150 tons going up, and it has to be able to land with its payload still aboard, in case it fails to make orbit. Return from hyperbolic entry may only be 1/2, so maybe 75 tons, but Musk keeps pushing the initial payload up. This was true for Shuttle as well (other than hyperbolic). Also note, Starship structural weight is only about half of Shuttle, so it’s fluffier during reentry.

  3. Regarding the rest of it, I wish Zubrin and others would quit pushing the trillion-dollar asteroid nonsense. Everyone needs to pay attention to Musk’s comment about the value of a crack cocaine asteroid. Asteroids are not ingots, or even high quality ores (unless we find out different at Psyche). Materials of value in space will mainly be of value in situ. The water on Mars, the lakes of rocket fuel on Titan, etc. All of that may not be true next century, but it’s true now. We are incredibly lucky that Musk has appeared at this point in history. In our time, the “killer app” for space is not trillion-dollar asteroids, it’s the pipe dreams of Elon Musk.

    1. You’re spot on. There “abundance” charts are juvenile, too many space cadets don’t know basic geology, mineralogy or mining technology. Magical thinking on par with “net zero” environmentalist nonsense. Embarrassing.

      1. Plus, the perception of abundance feeds into popular delusion.

        Asteroids are both a long way off and extremely widely scattered. The image of what amounts to a free-floating avalanche in space may make for thrilling cinema, but that’s all it is.

    2. Exactly. The value for this stuff is almost all in the fact that you don’t have to put it into orbit. Building stuff in orbit with it makes much more sense than deorbiting it.
      Sending it down to Earth is like throwing 99%+ of it away.

    3. Indeed. Further, orbital mechanics will play as large (or larger) role in the ability to recover and extract metals as sheer distance: When the targets and mars are on opposite sides of the solar system, it doesn’t matter a hell of a lot who’s mining

  4. I think asteroids near Mars could be mined from Mars, but I think main belt and beyond is better from Venus orbit. And water would be more valuable or higher price at Venus orbit. And I think Mars could export Mars water to Venus orbit. And Mars settlements and even early Mars crew missions should use Venus orbit.
    And I think largest market for water in space will be Venus orbit.
    One thing making Venus orbit useful is being able to do aero capture which has not been demonstrated, yet.
    So, do aero capture or aerobrake to Venus high orbit.

    1. Venus clouds have H2SO4. Wouldn’t it be easier to extract H2O from Venusian clouds and boost that to Venus orbit? And then why Venus orbit. Wouldn’t it be used in floating colonies in the Venusian clouds.

      1. It seems to me, that if Martian are growing food, they should export food. And food and water can exported with mass driver. And mass driver need lots of payload, so to start one export hundreds thousand of water per year.
        And without exporting Mars water, settlement need millions of tons of water and has to cheap water, something like $1000 per ton. And they should able to have CO2 at less than $100 per ton.
        The Moon is unlikely to have water at $1 per kg within a few decades and Mars needs to start at $1 per kg. But if the Moon get mass driver soon and there is a lot mineable on the Moon, it too have export water to Venus.

        1. If the Moon has water at $1000 ton and cheap CO2- it could have settlement- it just as habitable as Mars. But in near term we don’t regard the Moon as habitable. It’s possible the Moon has trillion of tons of mineable H20 and CO2, but few think it’s near the surface, but if hundreds of meter from the surface, counts as surface, it considered “possible/imagineable”.
          But it this point somewhere around 1 million tons of mineable water is plausible. If there only around 1 million ton , the Moon won’t be exporting a lot of water, maybe not even to Lunar orbit.
          But if there is not billions of tons of mineable water on Mars, it’s not a habitable planet.
          Mercury is thought to have trillions of tons of water at it’s poles- if it did, it’s a habitable planet.

  5. Unfortunately for that thought, Mars is not closer to the asteroids in time. Earth will have a launch window to any given belt asteroid about twice as often as Mars.

    1. With small rocks [100 meters or less] you impact them at low velocity on Mars surface and Mars moons- and Earth’s Moon.
      Or use space rocks similar to “nukes for peace” – https://world-nuclear.org/information-library/non-power-nuclear-applications/industry/peaceful-nuclear-explosions.aspx

      In terms of low velocity, space rocks hit Earth at average of 20 km/sec, and Mars is about 15 km/sec.
      Moon is about same as Earth, but space rocks can hit the Moon at very low velocity [like say 3 to 4 km/sec] and Mars moons would be similar and Mars around 5 km/sec. You get these low velocities because rocks hitting in hohmann transfer type trajectories. Whereas most impactors aren’t doing “hohmann transfer type trajectories”.
      There is some interest in looking for low impact impactors on the Moon, and they are something like 1% of all impactors.

  6. I always say, “First things first”. Too many space advocates focus on the distant future — O’Neillian, terraforming, SSP, asteroid mining, etc. Those visions may change radically by the time we get there. More important is what is right in front of us — Starship fleet, who will kick off permanence, surface technologies, International Lunar & Mars Bases, etc.

      1. A farside base would be a good place for radio astronomy for quite a while. There would be a trade in doing it all via robots/drones vs. having a crew there. Perhaps human-tended would be a better approach.

        One other activity a lunar base can do is prototype what you need for Mars colonization.

  7. Might I propose a use for asteroids?

    The ultimate power source! Take the asteroid, and subtly alter it’s orbit to impact Earth – right into the barrel of an impact target. The target then heats to ridiculous temperatures, which is then harvested to make electricity!

    Finally, a solution to the base load problem. In addition, a continuous stream of meteors impacting an area will likely dramatically improve the wind energy nearby! Win-Win!

    1. Remind me to pack an umbrella if I ever go within a 100 miles of that. Impactors will also heat the atmosphere above the impact site along with the thermal balancing around the impact site*. No doubt producing some interesting ‘meteorology”. Forgive the double entendre.

      *Reminded of the chordal asteroid that created the Fist of God and the forever storm on the other side of the Ringworld.

  8. My dad was a mineral commodities geologist, so we chatted about this stuff from my childhood in the 1950s until he died in 2015. In the wake of the Club of Rome report, we talked about space resources. He pointed out that a) the “Limits to Growth” data was a flat-out lie, and showed me raw Bu. Mines data to prove the basic resources as known back then wouldn’t run out for another 500 years, assuming no new discoveries, and b) returning resources from off Earth would require that either the cost of exploitation on Earth would become much more expensive, or space travel would become much cheaper, again, likely not for centuries. And, of course, in 1970, little was known about the resources of near-Earth space.

    1. One resource from space, could be lunar samples if you could get enough lunar samples are brought to Earth, per kg it could be priced somewhere around silver.
      It seems you would need at least need 100 tons of it.

      And then you don’t need simulated lunar soil, or perhaps one could “somehow” make better simulated lunar soil

      1. One result of it, is that more lunar rocks which impacted Earth might be found. Or within decade, or so, one find say 1000 tons them which are already on Earth.

  9. Google: how much water is in asteroids

    “How Much Water May Be Tucked Away in Nearby Asteroids? ”
    “By combining those observations with other measurements as well as data about meteorites that have fallen to Earth from asteroids, the team calculated a basic estimate for how much water could be trapped inside near-Earth asteroids. According to that estimate, there may be between 100 billion and 400 billion gallons (400 billion to 1,200 billion liters) of water spread among these space rocks.”
    So, 400 to 1200 million tons of water in NEOs. And if going to mine water in space, they probably are not [mostly] be from NEOs -or they will mostly be rocks
    which are further from the sun. And perhaps from something like Ceres for a lot of water.
    And the first million tons of water mined from rocks, will priced at about $100,000 per ton. So, the first 100 billion dollars of water.
    But first billion tons of water, could average about $10,000 per ton {gross of 10 trillion dollars}.
    And it seems where you want billion of tons of water {gold} sold, is in Venus orbit.
    But later and in terms trillions of tons of water [and much cheaper average price of water] it seems our
    lunar surface could import a fair amount of it. After you build a lunar space elevator.
    And you are wanting the hydro electrical power from the dropped water.
    Or pay for electrical power, and you get the water on lunar surface for “free”.

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