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Personally I'm rooting for the future where a fleet of falcon 9's launch escape velocity stage 2's that head straight for the sun. Underground is nice until yo

by elif 3y ago

Personally I'm rooting for the future where a fleet of falcon 9's launch escape velocity stage 2's that head straight for the sun. Underground is nice until you get radioactive groundwater. The time cost of 100k years of maintaining safety seems more than the financial cost of maintaining a F9 fleet and disposing of second stages.

lm28469 3y ago
Until one of them fails to launch or reach orbit
ttul 3y ago
My engineering students explored this idea for a project. It turns out that sending something into the sun is really difficult. You have to overcome the velocity of planet earth orbiting the sun, which means you need a delta-V of 8.8 km/s to get the waste into a high orbit above the sun, followed by another burn to reduce its velocity to zero at that orbit. That’s the same delta-V as going to Jupiter. You would need a lot of rockets.
spywaregorilla 3y ago
How many falcon 9's would that require?
xnx 3y ago
"...it's surprisingly hard to actually go to the Sun: It takes 55 times more energy to go to the Sun than it does to go to Mars. Why is it so difficult? The answer lies in the same fact that keeps Earth from plunging into the Sun: Our planet is traveling very fast — about 67,000 miles per hour — almost entirely sideways relative to the Sun. The only way to get to the Sun is to cancel that sideways motion." https://www.nasa.gov/feature/goddard/2018/its-surprisingly-hard-to-go-to-the-sun https://www.nasa.gov/feature/goddard/2018/its-surprisingly-h...
- ilyt 3y ago
  use solar sail to break into the sun ?
- elif 3y ago
  I dunno about 55 times more... Earth escape velocity is 11.2 km/s or 25,000 mph in your preferred units. And you don't have to go backwards relative to earths orbit and cancel it out, you can maintain earths' solar orbit and degrade it. You only need enough energy to reach L1 and since human time scales are irrelevant you can do that as efficiently as you like. After you reach slightly past L1, the sun will do the rest of the work. At closest approach, Mars is 54 million km away. L1 is typically 1.5 million km away. Even ignoring the fact that human timescales are irrelevant, it is a significantly easier journey. You are probably thinking of speeds required to orbitally maneuver near the sun, as we typically do with instruments... A trip straight into the sun is substantially easier than mars.
pintxo 3y ago
How would this ever be acceptable, given that rockets have a failure rate that’s not zero?
- acidburnNSA 3y ago
  Everyone suggests throwing it into the sun until they think about this fact. Stable geologic formations are far preferable, by orders of magnitude, for this reason.
- simmerup 3y ago
  The impossibility of getting an insurance policy to cover this downside probably makes it dead in the water unless a state starts doing it
  - pintxo 3y ago
    Didn’t stop us from using fission for energy production. But weapons production might have played a relevant role here.
  - panick21_ 3y ago
    If there were sea launch platforms its perfectly acceptable I would thin. And governments don't need insurance.
    - pintxo 3y ago
      How is a sea launch going to help with a late first stage, or 2nd stage malfunction leading to RUD?
      - panick21_ 3y ago
        Nuclear waste falling into the sea isn't optimal but it also isn't a huge issue. Nuclear waste falling onto a city or exploding on the launch pad would be an issue. The 2nd stage flight can be planned not to go over populated land. But anyways, I don't think its a good solution but it would be possible.
iso1631 3y ago
An Atlas V can get 400kg to the nearest star (well any star) by launching on a solar escape velocity -- see New Horizons. An expended F9 has a similar payload I think. You'd have to construct a container that would survive a failure - so an explosion of the rocket (on the pad or during launch), or a failure in LEO where it would have reentry. That container would then need to be able to be recovered no matter where it landed on that failure -- so things like floating would be important, and some form of control over landing so it didn't crash onto someones house. Or in an inconvenient country. Obviously it has to stay in one piece. Now sure, much of that shielding doesn't need to go beyond LEO, but it leaves very little room for the actual payload.
kuratkull 3y ago
Kurzgesagt: "Why Don't We Shoot Nuclear Waste Into Space?" https://www.youtube.com/watch?v=Us2Z-WC9rao https://www.youtube.com/watch?v=Us2Z-WC9rao Bad idea, it boils down to 1) too much of it (yes really, in an almost definitive sense) 2) exploding rockets + nuclear fuel is bad
pfdietz 3y ago
Falcon 9s are still too expensive, especially if you want to armor the spent fuel in case of launch failure. Disposal of troublesome fission products and actinides, on the other hand, could be much easier. There are seven fission products with troublingly long half lives that would be difficult to retain in geological repositories. Extraction and space disposal of the elements of those isotopes could make sense. In any case, space disposal can wait until launchers are mature and the technology has stopped improving. We have centuries before spent fuel stops being self-protecting against diversion due to its radioactivity, so stick the stuff in dry casks and wait.
Moldoteck 3y ago
Why throw goldmine into the sun? France already knows how to convert 95% of the 'waste' into new fuel, why just don't copy their approach and multiply by a factor of 10?

by elif 3y ago

lm28469 3y ago

Until one of them fails to launch or reach orbit

ttul 3y ago

My engineering students explored this idea for a project. It turns out that sending something into the sun is really difficult. You have to overcome the velocity of planet earth orbiting the sun, which means you need a delta-V of 8.8 km/s to get the waste into a high orbit above the sun, followed by another burn to reduce its velocity to zero at that orbit. That’s the same delta-V as going to Jupiter. You would need a lot of rockets.

spywaregorilla 3y ago

How many falcon 9's would that require?

xnx 3y ago

"...it's surprisingly hard to actually go to the Sun: It takes 55 times more energy to go to the Sun than it does to go to Mars. Why is it so difficult? The answer lies in the same fact that keeps Earth from plunging into the Sun: Our planet is traveling very fast — about 67,000 miles per hour — almost entirely sideways relative to the Sun. The only way to get to the Sun is to cancel that sideways motion." https://www.nasa.gov/feature/goddard/2018/its-surprisingly-hard-to-go-to-the-sun https://www.nasa.gov/feature/goddard/2018/its-surprisingly-h...

ilyt 3y ago
use solar sail to break into the sun ?
elif 3y ago
I dunno about 55 times more... Earth escape velocity is 11.2 km/s or 25,000 mph in your preferred units. And you don't have to go backwards relative to earths orbit and cancel it out, you can maintain earths' solar orbit and degrade it. You only need enough energy to reach L1 and since human time scales are irrelevant you can do that as efficiently as you like. After you reach slightly past L1, the sun will do the rest of the work. At closest approach, Mars is 54 million km away. L1 is typically 1.5 million km away. Even ignoring the fact that human timescales are irrelevant, it is a significantly easier journey. You are probably thinking of speeds required to orbitally maneuver near the sun, as we typically do with instruments... A trip straight into the sun is substantially easier than mars.

pintxo 3y ago

How would this ever be acceptable, given that rockets have a failure rate that’s not zero?

acidburnNSA 3y ago
Everyone suggests throwing it into the sun until they think about this fact. Stable geologic formations are far preferable, by orders of magnitude, for this reason.
simmerup 3y ago
The impossibility of getting an insurance policy to cover this downside probably makes it dead in the water unless a state starts doing it
- pintxo 3y ago
  Didn’t stop us from using fission for energy production. But weapons production might have played a relevant role here.
- panick21_ 3y ago
  If there were sea launch platforms its perfectly acceptable I would thin. And governments don't need insurance.
  - pintxo 3y ago
    How is a sea launch going to help with a late first stage, or 2nd stage malfunction leading to RUD?
    - panick21_ 3y ago
      Nuclear waste falling into the sea isn't optimal but it also isn't a huge issue. Nuclear waste falling onto a city or exploding on the launch pad would be an issue. The 2nd stage flight can be planned not to go over populated land. But anyways, I don't think its a good solution but it would be possible.

iso1631 3y ago

An Atlas V can get 400kg to the nearest star (well any star) by launching on a solar escape velocity -- see New Horizons. An expended F9 has a similar payload I think. You'd have to construct a container that would survive a failure - so an explosion of the rocket (on the pad or during launch), or a failure in LEO where it would have reentry. That container would then need to be able to be recovered no matter where it landed on that failure -- so things like floating would be important, and some form of control over landing so it didn't crash onto someones house. Or in an inconvenient country. Obviously it has to stay in one piece. Now sure, much of that shielding doesn't need to go beyond LEO, but it leaves very little room for the actual payload.

kuratkull 3y ago

Kurzgesagt: "Why Don't We Shoot Nuclear Waste Into Space?" https://www.youtube.com/watch?v=Us2Z-WC9rao https://www.youtube.com/watch?v=Us2Z-WC9rao Bad idea, it boils down to 1) too much of it (yes really, in an almost definitive sense) 2) exploding rockets + nuclear fuel is bad

pfdietz 3y ago

Falcon 9s are still too expensive, especially if you want to armor the spent fuel in case of launch failure. Disposal of troublesome fission products and actinides, on the other hand, could be much easier. There are seven fission products with troublingly long half lives that would be difficult to retain in geological repositories. Extraction and space disposal of the elements of those isotopes could make sense. In any case, space disposal can wait until launchers are mature and the technology has stopped improving. We have centuries before spent fuel stops being self-protecting against diversion due to its radioactivity, so stick the stuff in dry casks and wait.

Moldoteck 3y ago

Why throw goldmine into the sun? France already knows how to convert 95% of the 'waste' into new fuel, why just don't copy their approach and multiply by a factor of 10?