I received a plethora of email from the Fox News piece on nuclear waste disposal. I’m going to put up a little FAQ here that responds to the majority of it. Then I’ll let the fray take place in the comments section.

Why is this even an issue? Isn’t Yucca Mountain is a reasonable and safe way to store it?

Yes, but people aren’t rational. We might be able to take advantage of their irrationality to develop space.

Which leads to the other popular and reasonable question:

The watermelon environmentalists went nuts over a little plutonium on Galileo and Cassini. Why do you think they’d let us get away with something like this?

Well, the question is not whether or not they’ll oppose it, but whether or not their opposition will be effective. I’m cautiously optimistic because 1) their credibility as of recent years has been on the wane, 2) people are less likely to put of with such anti-tech nonsense post 911, and 3) there will be a newfound sense that anything we can do to utilize new energy sources that free us from Middle East oil is worth doing.

That is not to say that they can’t stop it–just that there is cause for hope.

This next one was a popular one. Please don’t send me any more, even though each mention of it was hilarious, and had me falling out of my chair with helpless laughter. Anyone who does will be hunted down and killed, painfully:

Remember that show from the ’70s, Space: 1999? And Martin Landau and the bell-bottom uniforms?

Yes.

I’d almost forgotten it.

Now I have to do so again.

Thanks a lot.

Are you trying to destroy the nuclear industry by making it too expensive?

Well, actually, the NRC’s been doing a pretty good job of that for decades, without any assistance from me. Every method proposed to deal with nuclear waste is ridiculously expensive, including Yucca Mountain. I’ve simply selected an expensive means that also provides a useful spinoff–cheap and reliable space access.

Wouldn’t it make the Moon harder to colonize, with all that radioactive waste up there?

Any technology that can handle lunar colonization will consider nuclear waste to be way down the list of environmental problems, after total vacuum, thermal extremes, dust, lack of water and essential nutrients, and the occasional solar flare. This is not to say that lunar colonization will be impossible, or even difficult–just that nuclear waste will not present much of a difficulty relative to the natural ones.

Why would it be more expensive to just drop it into the Sun?

To understand this requires a little basic orbital mechanics.

An object in orbit has a certain velocity needed to keep it from falling toward the thing that it’s orbiting around. In order for it to fall, it has to be slowed down.

For an object going around the sun (like the earth, and anything on it) that velocity is the distance traveled divided by time, or about 600 million miles per year, or about 70,000 miles an hour. That’s roughly how much an object on earth must be slowed down in order for it to fall into the sun.

To get to the Moon, on the other hand, is more like 25,000 miles per hour. Quite a bit easier (particularly when one considers that the propellant required is an exponential function of the velocity change–a factor of three difference in velocity means a factor of 2.7^3 or 20 times as much propellant…)

Waste isn’t a problem if you use breeders. Didn’t you know that, dummy?

Well, actually, I did. I was ignoring breeders for the purpose of that article. When I said it’s a problem independent of design, I was referring to non-breeder design. I think that breeders are a tough sell, politically, for a number of reasons.

I’ve seen pictures of the Shuttle blowing up, over and over and over and over and over. How can we ever build a launch system that won’t blow up and scatter waste all over the place, killing us all?

Well, OK, no one asked it quite like that, but you know that’s what lots of people are going to think, and people are legitimately concerned about reliability and safety. There’s an answer, but I don’t have time to post it right now (kind of like Fermat’s Last Theorem). I’ll get to it a little later today, but I’ve got other stuff to do right now, and I want to at least post what I’ve done so far.

[Update: 1:56 PM PST]

OK, here’s the story.

There are two ways to deal with this:

1) Make the vehicle extremely reliable so it almost never has a catastrophic failure.
2) Package the payload such that if such a failure occurs, no radioactive material can be released.

Both of these are technically and economically achievable. As I said in the column, do not look to any existing launch vehicle as in any way representative of what is achievable in either cost or reliability for space transports.

Expendables are very expensive because we throw the hardware away every time. They’re unreliable because every flight is their first–they suffer from the “infant mortality” phenomenon.

Shuttle is expensive because it’s partly expendable, and because it wasn’t designed for a high flight rate, and it’s not flown at a high flight rate, so there are no economies of scale.

A new, fully-reusable space transport, flown at the high flight rates required would suffer from neither of these problems. In fact, I would expect to see several hundred consecutive successful flights of such a system before we would commit to using it for such a program.

As to the second means, payload canisters can be designed that will survive any conceivable launch accident, or reentry from orbit, without releasing any of the waste. This adds weight, and hence cost, but not so much as to necessarily make it unaffordable. Again, this can be demonstrated, using an inert payload.

And finally of course, the perennial question, probably from a Fox Network (not Fox News) viewer:

DID WE REALLY GO TO THE MOON?

Obviously, the questioner somehow feels that the question has more urgency, and less kookiness, if it’s asked with the shift key locked…

Answer: No. “WE” didn’t. But several American astronauts did. No further comment.