[dpark]

Why would launch costs be low? $10/kg is fantasy land. UPS won’t ship a kilogram across the country for $10.

And who wants spent nuclear fuel in low earth orbit? This is a far worse location for spent fuel than buried in a bunker. This is a worse location than Times Square.

[fc417fc802]

> UPS won’t ship a kilogram across the country for $10.

I can purchase produce grown on a different continent for less than that at the grocery store so something isn't right here.

[dpark]

It was a metaphor for how absurd the statement was. But if you try to ship a 1kg package across the country it will likely cost way more than $10.

Freight cost is certainly way lower.

[pfdietz]

Why wouldn't they be low? In the limit, if launch becomes operationally similar to air travel, costs will be a few times propellant cost. And propellant is very cheap. LOX is almost free (the second cheapest industrial liquid after water) and liquid methane isn't very expensive either.

Low earth orbit would just be where it's transferred to something to carry it farther out, for example using solar-electric engines.

For all this, remember it isn't done immediately, it's done in (say) 300 years when the short lived fission products are mostly gone.

[dpark]

I think the onus is on you to explain why costs would drop by >3 orders of magnitude (>4 accounting for the 10x launch armor). It’s something like $1500/lb on a fully loaded Falcon Heavy and all indications are that SpaceX isn’t making money at that price.

Plus even if this were free, “shoot 180k tons of nuclear waste into space” seems like a terrible idea in general. It’s one of those ideas that make sense only until you think about the ramifications. What happens when inevitably one of the 3 thousand Falcon heavy rockets explodes and the armor fails and we spread nuclear waste over 3 states?

[pfdietz]

Falcon Heavy is more expensive per kg than F9, because it throws away more things. SpaceX flies it for certain military missions but you will note they launch their own stuff on F9.

A full launch on F9 (with recovered S1) is estimated to cost $15M and can put up to 17,600 kg into LEO, or $850/kg.

> (>4 accounting for the 10x launch armor).

You're double counting there. 3x would be just fine even with 10x launch armor.

> seems like a terrible idea in general

And here's the problem: you started from an emotional reaction and are trying to rationalize that.

[dpark]

> A full launch on F9 (with recovered S1) is estimated to cost $15M

Estimated by who? SpaceX charges 74 million for this. Nothing credible I can find indicates that SpaceX is running an amazing 80% profit margin on Falcon 9 launches.

> And here's the problem: you started from an emotional reaction and are trying to rationalize that.

No, your premise is “just launch the trash into space” and you’re hand waving away the complexity, costs, and danger.

[pfdietz]

SpaceX charges what the market will bear, and because they have no good competitor their profit margins can be very large.

Anyway, the number is from fairly old Musk interviews. Costs have likely decreased since then.

https://www.nextbigfuture.com/2026/02/spacex-falcon-9-true-c...

> No, your premise is “just launch the trash into space” and you’re hand waving away the complexity, costs, and danger.

At least I didn't trot out a string of obvious errors like you did.

When people do that, it's a strong tell they're engaging in broken thinking. What you did, I think, is believe something, then try to rationalize it. When your thinking reached a justification you liked you just stopped thinking (because, after all, thinking more could break the pleasing argument you just constructed, and that would feel bad).

[dpark]

> SpaceX charges what the market will bear, and because they have no good competitor their profit margins can be very large.

Is your premise that SpaceX will ship nuclear waste at or below cost? Because the 74 million is a publicly available price. And when SpaceX ships stuff for the government the prices go up, not down.

> Anyway, the number is from fairly old Musk interviews.

Yes, Musk is famously honest and accurate with his claims.

> At least I didn't trot out a string of obvious errors like you did.

What obvious errors are those? You don’t seem to like that I’m using publicly available pricing.

> When people do that, it's a strong tell they're engaging in broken thinking. What you did, I think, is believe something, then try to rationalize it. When your thinking reached a justification you liked you just stopped thinking

Pot, meet kettle. You are basing your entire premise on a speculative future that doesn’t exist. You should have just proposed sending it up the space elevator.

None of this idea makes sense from a financial, physical, or risk stand point. “This stuff is too dangerous to store in a hole, let’s launch it into space in 3000 rockets, and then we’ll push it away from earth with another thousand solar electric rockets, and then we’ll use solar energy to evaporate it all! What could go wrong?”

Honestly if you’re betting on a hypothetical future where all this is effectively free, why not just bet on a future where reprocessing uranium drops in price as well?

[api]

$10/kg isn’t fantasy land if we have fusion rockets, but then we don’t need fission power anymore. :)

[pfdietz]

Fusion would be useless for launch to orbit. Even fission sucks for that. It's really hard to beat the cost and power density of chemical rockets.

[api]

Depends. If we get explosive inertial confinement fusion to work you could build a pure fusion version of a nuclear pulse rocket. Look up Project Orion.

Orion (in its fission bomb form) is impractical and would be insane to launch from Earth, but it holds the title of being the only “torch ship” drive we know how to build. We could technically build it.