Fission fuel is barely radioactive before you start the reactor. It's just natural uranium, with a modestly higher percentage of U235.

It's the broken-apart atoms you get after fissioning uranium that are the really dangerous stuff. And to a lesser extent, heavier atoms that absorbed neutrons without splitting. So, just don't start the reactor until you're well away from Earth.

That would be way safer than what NASA has actually done multiple times, which is launch deep space missions powered by plutonium-238. That doesn't even need to be fissioned, its radioactivity is what powers the mission.

Qplasma > 1 has never been done before. It's a serious milestone that scientists have been pursuing for 70 years. It's just not a practical power plant yet. But it does mean the plasma gets more energy from fusion than from the laser, which is likely to help with experiments to improve the yield further.

The lasers are very inefficient but that's because they date back to the 1990s. Equivalent modern lasers are over 20% efficient.

Also, they increased the laser output by 8% and got 230% more fusion energy.

Russia isn't the only producer though. Your link says it's not even the only supplier CFS is using.

Yep, they spun off from MIT and got a bunch of funding.

The link I posted puts NIF laser efficiency at 0.5%. Either way, roughly one order of magnitude gets us over practical breakeven. Get to 20X and we've got a solid margin. Two orders of magnitude would be around 100X but we don't need to go near that far.

Equivalent modern lasers are 40 times more efficient than NIF's lasers. 40MJ output would be plenty.

ITER is the world's slowest fusion project. CFS is doing the same thing with a reactor a tenth the size, because unlike ITER they're using modern superconductors. They'll be starting fusion experiments a decade earlier.

For your "small fusion breakthrough," Helion seems to have a good shot at it. They're building their seventh reactor, for a net power attempt in 2024 with advanced fuel and direct electricity extraction.

Yep SPARC is a tokamak. It's about a tenth the size of ITER, but should get the same output because they have better superconductors. Tokamak output scales with the fourth power of magnetic field strength: double the field, 16X the output.

First plasma at ITER got delayed several years because a big crack developed in something important. After first plasma it'll be a decade before they make their net power attempt with D-T fuel.

Luckily, CFS is building a much smaller reactor that should do the same thing, because they're using modern superconductors that support stronger magnetic fields. They actually should have it up and running in 2025, and don't plan to wait long before attempting net power.

The article does not say we're 2 to 3 orders of magnitude away. It does mention that we have much better lasers now.

NIF's lasers date back to the 1990s and are only 0.5% efficient. We have NIF-class lasers now that are over 20% efficient. That drops the input power to the lasers by a factor of 40.

So if NIF manages to increase the fusion output by a factor of ten, we can substitute modern lasers and have enough extra power to be net positive after running a turbine.

Delta-v to launch from the surface and dock with the space elevator, according to the article: 0.52 km/sec.

Delta-v to launch from the surface into Martian low orbit: 3.8 km/sec.

So less than a seventh as much velocity change. Now let's use the rocket equation. A methane rocket has specific impulse of about 370 seconds (that's a measure of how fuel-efficient the rocket is). We'll use a starting mass including fuel of 10,000 kg.

For a delta-v of 520 m/sec, we get a final mass of 8380 kg. We only had to burn 1620 kg of fuel to get 8380 kg of rocket and payload up to the elevator.

For a delta-v of 3800 m/sec, our final mass is only 2748 kg. We had to burn 7250 kg fuel, to put only 2748 kg of rocket and payload into orbit.

Assume in both cases that the rocket is 1000 kg, then with the space elevator we're getting 7380/1620 = 4.55 kg payload per kg fuel, and without the space elevator we're getting 1748/7250= 0.24 kg payload per kg fuel.

And if a big bitcoin miner manages a 51% attack, they can just keep doing doublespends until someone else manages to set up more mining machines. If a 51% Ethereum staker does a doublespend, they immediately lose all their stake.

For Ethereum's energy usage, there's a peer-reviewed [paper](https://www.cell.com/patterns/fulltext/S2666-3899(22)00265-3) linked right from the article OP posted. It puts Ethereum's worst-case power demand at 675 kW, and best-case only 36 kW.

I haven't been able to track down how much Reddit's datacenter uses, but I'm guessing it's more than that. Reddit is one of the world's largest sites, and some large datacenters use more than 100 MW.

Ethereum's stakers play exactly the role that Bitcoin's miners play. They have no special governance rights or abilities. Some other blockchains do give stakers special governance rights but Ethereum does not.

No more than big miners control Bitcoin.

There are tradeoffs. On the one hand, PoS is more complicated. On the other, PoS gives you the option of applying penalties instead of just rewards. It's like you can respond to a large attacking miner by burning down their mining rig. This happens in Ethereum's PoS automatically in response to certain specific attacks.

Total energy used by the Ethereum network now is about the same as a hundred average American households. I wouldn't call that a huge amount.

No more than with mining. Those giant datacenters aren't free.

Some of the older staking protocols are pretty centralized because they use a handful of full staking nodes, with everyone else delegating to those. Ethereum got lucky, there was a breakthrough in cryptography that allowed them to do things in a much more scalable way and support millions of full staking nodes. Currently there are over 400,000.

No reddit would save a lot more than Ethereum's remaining energy usage, but here you are.

Contrary to popular belief, Bitcoin actually does have developers who work on upgrades. Taproot for example was a recent Bitcoin upgrade.

Bitcoiners won't do it but they absolutely could, just like Ethereum did.

He didn't buy SpaceX.

So, an AI system that's trained to convince humans it's acting in their best interests, and then destroy them. Just what we need!

We didn't have cheap launch back then, the beam wouldn't be concentrated enough to harm birds, and solar panels on earth need expensive batteries for power at night.