It's not the safety. One could conceivably put a glas she'll around the burnt fuel and it would survive reentry.

But first of all, the cost is still massive, even with SpaceX. And furthermore, you'd just put it into (decaying) low earth orbit that way. Further away would be even more expensive.

Finally, spent fuel still contains a lot of energy and should be recycled. This in turn is a very nasty and expensive procedure.

I still think that declaring that waste is a waste.

That is potential future fuel.

The danger of launch failure making the planet uninhabitable.

lol, good point. that's the sort of thing that's easy to forget about when your involvement on a topic is limited to typing out comments on HN.

How do you imagine that would happen? Even if a rocket fails catastrophically, pulverizing the nuclear waste, distributing it evenly across earth, how do you imagine that would make the planet inhabitable? Is the planet inhabitable now, after all the atomic bombs that exploded and all the nuclear waste that went into the ocean?

And what do you think drives the latest Mars rover, Perseverance?