Naked and Screaming into Space
I've got a term for how we can get the costs of human space launches down. I call it "Naked and Screaming". It's based on the idea that the cheapest possible way to get someone into space, would be to simply strap them onto the nose of a rocket, and launch them "naked and screaming" to low earth orbit. Start from that perspective, then work your way backwards to the minimum cost method of getting someone safely and reliably to LEO.
If we assume an 80kg astronaut, at perhaps $10000/kg to LEO - the "naked and screaming" price might be $800,000. Not exactly the price of a vacation plane ticket - but perhaps affordable for a corporation that needed a human operating in space.
But obviously we can't *really* send them up naked. No one could hear them scream out there, anyhow... And perhaps we'd like to somehow be able to send them somewhere useful?
That's where most manned space programs start to go wrong, I think. They start thinking in terms of "safely up, safely back" as a single mission. What if, instead, when the astronaut wants to come back, he or she could reliably rendezvous with a re-entry vehicle already in orbit? How convenient - that'd shave a LOT of launch mass - no need to make the launch capsule able to withstand the stresses of re-entry, no heat shield - in fact, once the launch craft gets out of the atmosphere, the astronaut really wouldn't NEED a capsule - just a space suit. Surely that's better than naked, and maybe after a few flights, they'd be able to stop screaming. If they can't, or they're a first-timer, we'd just turn their helmet visor opaque until they get into orbit. It's not like they have to fly the rocket.
So we have to have an aero-shell while in the atmosphere, but could eject everything but the astronaut and air tanks after the first few minutes of the launch. That in turn reduces the size of the final stage or stages. In fact, it may reduce launch mass so much, that we'd have to make it bigger again, by launching lots of space workers (they don't get to be called astronauts if they're going to space to do more than travel through it) at a time - rockets can only be made efficient by making them fairly large, and a lot of the costs of launch are close to fixed, no matter how big the rocket is. E.g. you may need a ground crew of 100 for one astronaut, but only 110 to launch 30 space workers.
Since we're letting them have a space suit and air, and maybe a cushioned chair, let's suppose each worker launched costs us the equivalent of 150kg to LEO - taking us up to $1.5M per worker. But if we're going to be launching frequently, we'd start to share fixed costs over more flights. Most experts claim this should get the price per kilogram down - so perhaps we can safely assume it's reduced to $5000 per kg, or $750,000 per worker. Maybe even half that, since really big rockets already approach that price per kilogram.
Of course, we've still got some problems. LEO isn't terribly useful - there's nothing much there to for our space workers to work on - we need a ship to take them somewhere they can be useful. But maybe we can just launch that ship from Earth ONCE, and use it lots and lots of times, to keep costs down. And if we produce the fuel for it on the moon, that gives us both a destination AND a place to refuel for the next trip.
The money saved by not launching so much mass from Earth creates a sort of "double-negative" profit - i.e. cancelling a cost is almost as good as making a real profit, so long as you're going to go into space anyhow to explore. We could bootstrap an economy in space on that basis, and once there's a bunch of people staying in space for a long time, that economy could become more and more self-sustaining, needing less and less from Earth, even as they start to provide a few things Earth might want to buy (solar energy, rare metals, perhaps Helium 4 for fusion power) beyond the knowledge that explorers would bring back.
What about getting people back? Didn't you read the previous paragraph? If we LEAVE them there, they'll create an economy and... Oh, all right, maybe we should let them come back. But again, we should think in terms of launching as much mass from the moon, and as little as possible from Earth. With a decent lunar industrial base, we ought to be able to make things like re-entry capsules fueled rockets, so we can slow them down instead of relying so much on risky aero-braking. Or since they'd be launched from the moon - no air to create the friction that limits rockets launched from Earth to tall and skinny - the capsules could be made very wide and light, so they'd slow down faster in the upper atmosphere.
Well, that's pretty much it, except that there's a lot more details. Like - we need to really conquer cancer, so we can live and work in space for extended periods without killing ourselves. And investigate tether technologies, to start conserving momentum so we can stop throwing away so much valuable mass to get anywhere in space. (Fusion powered rockets wouldn't hurt, either, but that's not really specific to the "naked and screaming" approach.)
If we assume an 80kg astronaut, at perhaps $10000/kg to LEO - the "naked and screaming" price might be $800,000. Not exactly the price of a vacation plane ticket - but perhaps affordable for a corporation that needed a human operating in space.
But obviously we can't *really* send them up naked. No one could hear them scream out there, anyhow... And perhaps we'd like to somehow be able to send them somewhere useful?
That's where most manned space programs start to go wrong, I think. They start thinking in terms of "safely up, safely back" as a single mission. What if, instead, when the astronaut wants to come back, he or she could reliably rendezvous with a re-entry vehicle already in orbit? How convenient - that'd shave a LOT of launch mass - no need to make the launch capsule able to withstand the stresses of re-entry, no heat shield - in fact, once the launch craft gets out of the atmosphere, the astronaut really wouldn't NEED a capsule - just a space suit. Surely that's better than naked, and maybe after a few flights, they'd be able to stop screaming. If they can't, or they're a first-timer, we'd just turn their helmet visor opaque until they get into orbit. It's not like they have to fly the rocket.
So we have to have an aero-shell while in the atmosphere, but could eject everything but the astronaut and air tanks after the first few minutes of the launch. That in turn reduces the size of the final stage or stages. In fact, it may reduce launch mass so much, that we'd have to make it bigger again, by launching lots of space workers (they don't get to be called astronauts if they're going to space to do more than travel through it) at a time - rockets can only be made efficient by making them fairly large, and a lot of the costs of launch are close to fixed, no matter how big the rocket is. E.g. you may need a ground crew of 100 for one astronaut, but only 110 to launch 30 space workers.
Since we're letting them have a space suit and air, and maybe a cushioned chair, let's suppose each worker launched costs us the equivalent of 150kg to LEO - taking us up to $1.5M per worker. But if we're going to be launching frequently, we'd start to share fixed costs over more flights. Most experts claim this should get the price per kilogram down - so perhaps we can safely assume it's reduced to $5000 per kg, or $750,000 per worker. Maybe even half that, since really big rockets already approach that price per kilogram.
Of course, we've still got some problems. LEO isn't terribly useful - there's nothing much there to for our space workers to work on - we need a ship to take them somewhere they can be useful. But maybe we can just launch that ship from Earth ONCE, and use it lots and lots of times, to keep costs down. And if we produce the fuel for it on the moon, that gives us both a destination AND a place to refuel for the next trip.
The money saved by not launching so much mass from Earth creates a sort of "double-negative" profit - i.e. cancelling a cost is almost as good as making a real profit, so long as you're going to go into space anyhow to explore. We could bootstrap an economy in space on that basis, and once there's a bunch of people staying in space for a long time, that economy could become more and more self-sustaining, needing less and less from Earth, even as they start to provide a few things Earth might want to buy (solar energy, rare metals, perhaps Helium 4 for fusion power) beyond the knowledge that explorers would bring back.
What about getting people back? Didn't you read the previous paragraph? If we LEAVE them there, they'll create an economy and... Oh, all right, maybe we should let them come back. But again, we should think in terms of launching as much mass from the moon, and as little as possible from Earth. With a decent lunar industrial base, we ought to be able to make things like re-entry capsules fueled rockets, so we can slow them down instead of relying so much on risky aero-braking. Or since they'd be launched from the moon - no air to create the friction that limits rockets launched from Earth to tall and skinny - the capsules could be made very wide and light, so they'd slow down faster in the upper atmosphere.
Well, that's pretty much it, except that there's a lot more details. Like - we need to really conquer cancer, so we can live and work in space for extended periods without killing ourselves. And investigate tether technologies, to start conserving momentum so we can stop throwing away so much valuable mass to get anywhere in space. (Fusion powered rockets wouldn't hurt, either, but that's not really specific to the "naked and screaming" approach.)
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