It would be burned to a crisp long before it reaches the sun, so that's a moot point. Doubly so since it's also extremely expensive to escape our orbit...
How can this really be a question? It's obvious that it's expensive to launch things in rockets: that has very little to do with the orbital mechanics nerding out of "actually you can't just fall into the sun, you need a surprising amount of delta-v" and everything to do with the cost of building skyscraper-sized shiny single-use machines that are 90 parts fuel, 9 parts expensively machined metal, and 1 part "garbage" payload.
In other words, launching garbage in any kind of rocket is incredibly inefficient compared to dumping it on the ground or into the ocean, so the consideration of "would it be cheaper to send it to the Sun or Jupiter" doesn't really come into question.
But could we accelerate the payload using something other than a rocket? After all G-forces are not an issue for garbage. Assuming you could get to orbit, how much fuel would it take to get it going in the right direction and then have gravity do all the work?
If we're saving it for later (but for some reason don't want it on Earth) we should just launch it into orbit around the Earth. Why waste the fuel to send it outside Earth orbit just to need it back later. Even if we wanted to use the materials somewhere else in the solar system, just park it in orbit around Earth until its time to move it.
Weird, I didn't find the term "delta-V" anywhere in the article. Most on HN probably know this but delta-V is the change in velocity required to reach some goal.
Fun fact: it requires more delta-V to hit the Sun than it does to leave the Solar System. For giggles, here's a delta-V map of the Solar System [1].
Of course there's the issue of getting things off Earth to begin with but even if you take that as (economically) solvable the detla-V problem remains.
Site note: there are lots of proposals for cheaper LEO solutions (in $/kg terms). Probably the most famous is the space elevator but that's actually a bad solution for many reasons and possibly not even feasible since we'd have to invent a material strong enough.
What could well reduce that from $thousands/kg to <$10/kg is an orbital ring [2] (and check out the rest of his Uplift series if you're interested at the other options). The beauty of this is it doesn't require any magical material (cough graphene cough) and requires no new physics. It's largely just an engineering problem. Granted it's a massive engineering problem.
To be fair, the article does mention how much energy you'd have to lose but it strikes me as just being so much easier to explain in delta-V terms.
> Fun fact: it requires more delta-V to hit the Sun than it does to leave the Solar System.
Isn't that the delta-v needed to reach a stable orbit? That is, to slow down and counteract all the kinetic energy you gained from the sun's gravity. To just hit the sun (with high velocity) you wouldn't need to do that.
Yes, moving towards sun/ any body that is inbeteen sun and earth you actually 'slowing down' (after reaching earth's orbit). When you reach zero V relative to sun you will just drop to its surface (same with any other planet).
Anything on the outside you 'speedup'.
That's why its called delta-V as its relative change in V needed to get somewhere. And its independent of size, type of craft etc.
> Probably the most famous is the space elevator but that's actually a bad solution for many reasons and possibly not even feasible since we'd have to invent a material strong enough.
That's true, after all we are still stuck trying to invent materials light enough to make areoplanes actually fly /s
Sorry couldn't help it :)
Pushing what is currently impossible is how we got where we are. We already have viable tech to capture asteroid that could be used as counterweight for space elevator.
> Pushing what is currently impossible is how we got where we are.
This is a tired cliche at this point. Yes the track record for what is "impossible" (flying, going to the Moon and so on) could lean one towards saying nothing is impossible but take that to the extreme and what's left? Is breaking the second law of thermodynamics "impossible"? Time travel? Wormholes? FTL?
Engineering is ultimately limited by physics and the physics for a space elevator are dire. You need a material with a tensile strength such that it can withstand the centrifugal forces of being 35,000km+ long including having a counterweight pulling on it to counterbalance the force of gravity acting on the mass of that.
At this point only theoretical materials come close to that.
But even if you can solve the tensile strength problem (and that may well be solvable) you're left with a structure that isn't really as useful as you might think.
Even getting between the geosynchronous point and the Earth requires speeding up and slowing down for a distance of 35,000km+. Average 1000km/h and you're still talking 35 hours. 1G of acceleration and deceleration could cover this distance a lot quicker but there are limits to how fast you can go when you need to stay attached to a column the whole way.
But let's say you can solve that problem and get to geosynchronous orbit in reasonable time. Now what? Well if you want to go anywhere you need to accelerate. You need to bring the fuel for that.
Now compare this to an orbital ring. An orbital ring:
- doesn't require any magical materials. The core of it is nothing more than copper or iron cabling;
- will get you get to and from different points on the Earth much faster;
- provide LEO space to live and work on the stationary (relative to the surface of the Earth) platform. At 20 meters wide you're talking ~1 billion square meters of area, which is almost as large as the land area of Los Angeles;
- allows for huge amounts of solar power to be generated and sent to the ground via transmission cables;
- provides you with enough delta-V to escape the Solar System for almost no cost; and
- has significantly more attractive failure modes. If an orbital ring severs it'll likely fly off into space based on inertia. If a space elevator severs part of it is likely to fall to the ground, which would be... bad.
This is like asking why we don't use the Large Hadron Collider to make toast, and then answering by going into detail about how tricky it would be to coax the LHC into making toast of acceptable quality.
We don't do it because you don't use hyper-expensive mega-engineering to solve mundane problems with easy solutions, like "where do I put my banana peel".
There might be a slightly modified version of this question which might actually make sense: "Why we don't shoot nuclear waste into the Sun".
Surely, the cost of storing that type of waste here (on Earth) is very expensive, both from economical perspective and from risk management perspective. It could be very interesting to compare the costs of sending 1kg of nuclear waste into the sun (or out of our solar system, if that makes it cheaper) compared to storing 1kg of nuclear waste anywhere here on Earth, + adding the cost of the infrastructure that is required to actually store and preserve that waste, + adding the cost of people that are required to protect that infrastructure (a facility of some sort), etc...
No infrastructure or crew is required to "protect" the "infrastructure" around a glass log on the ocean floor for the ~500 years it takes it to become as radioactive as natural uranium ore.
Why don't we discuss this easy disposal option seriously? Why do we instead ask seriously about launching it into the sun instead?
Because nuclear waste has been politicized to such an extent that most people have no idea what it is composed of, what the halflifes of its constituents are, how radioactive it is, how chemically reactive it is or even what state of matter it is in. But everyone knows that, like, it is, like, totally dangerous!
Even if it would be cheap to launch junk into space, we'd still have to solve some of the same issues we'd have to solve now as well: collection.
To put it on a rocket, you'd have to collect the junk first, which we currently don't do well (except in a couple of countries).
Nuclear waste is well collected though, I'd say.
Breaking that down to it's constituent protons and neutrons would make it harmless right? Though I have no idea how much energy that would cost, only that the lower bound is probably well above what is reasonable.
Even if we had a cheap, reliable way of sending garbage to the sun I am skeptical of the idea that the garbage would just magically disappear. It would probably accumulate into another problem later down the road.
Exactly, our garbage is made up of the most valuable elements on earth, as proven by the fact that they were used to make useful products, eventually we will be mining garbage to extract the value once the cost is cheaper than traditional mining. If we launch it into the sun eventually there will be a resource shortage of some kind.
One alternative could be instead of shooting surface based garbage into the Sun can we not not just sequester the thousands of dead/decommissioned/dangerous human launched objects orbiting around our planet and launch them towards Sun?
42 comments
[ 2.7 ms ] story [ 81.3 ms ] threadIn other words, launching garbage in any kind of rocket is incredibly inefficient compared to dumping it on the ground or into the ocean, so the consideration of "would it be cheaper to send it to the Sun or Jupiter" doesn't really come into question.
As in?
but would still be a stupid idea. everything is recyclable
https://en.wikipedia.org/wiki/A_Big_Piece_of_Garbage
Why do we think we have the right to blast our junk into space?
Who does the cleanup when a rocket explodes after launch and covers Florida/Guyana/Khazakstan in used diapers and hypodermic needles?
Fun fact: it requires more delta-V to hit the Sun than it does to leave the Solar System. For giggles, here's a delta-V map of the Solar System [1].
Of course there's the issue of getting things off Earth to begin with but even if you take that as (economically) solvable the detla-V problem remains.
Site note: there are lots of proposals for cheaper LEO solutions (in $/kg terms). Probably the most famous is the space elevator but that's actually a bad solution for many reasons and possibly not even feasible since we'd have to invent a material strong enough.
What could well reduce that from $thousands/kg to <$10/kg is an orbital ring [2] (and check out the rest of his Uplift series if you're interested at the other options). The beauty of this is it doesn't require any magical material (cough graphene cough) and requires no new physics. It's largely just an engineering problem. Granted it's a massive engineering problem.
To be fair, the article does mention how much energy you'd have to lose but it strikes me as just being so much easier to explain in delta-V terms.
[1]: https://external-preview.redd.it/U5iH7huE5qKth7ZFvipXt8vzaFO...
[2]: https://www.youtube.com/watch?v=LMbI6sk-62E
Isn't that the delta-v needed to reach a stable orbit? That is, to slow down and counteract all the kinetic energy you gained from the sun's gravity. To just hit the sun (with high velocity) you wouldn't need to do that.
Anything on the outside you 'speedup'.
That's why its called delta-V as its relative change in V needed to get somewhere. And its independent of size, type of craft etc.
That's true, after all we are still stuck trying to invent materials light enough to make areoplanes actually fly /s
Sorry couldn't help it :)
Pushing what is currently impossible is how we got where we are. We already have viable tech to capture asteroid that could be used as counterweight for space elevator.
This is a tired cliche at this point. Yes the track record for what is "impossible" (flying, going to the Moon and so on) could lean one towards saying nothing is impossible but take that to the extreme and what's left? Is breaking the second law of thermodynamics "impossible"? Time travel? Wormholes? FTL?
Engineering is ultimately limited by physics and the physics for a space elevator are dire. You need a material with a tensile strength such that it can withstand the centrifugal forces of being 35,000km+ long including having a counterweight pulling on it to counterbalance the force of gravity acting on the mass of that.
At this point only theoretical materials come close to that.
But even if you can solve the tensile strength problem (and that may well be solvable) you're left with a structure that isn't really as useful as you might think.
Even getting between the geosynchronous point and the Earth requires speeding up and slowing down for a distance of 35,000km+. Average 1000km/h and you're still talking 35 hours. 1G of acceleration and deceleration could cover this distance a lot quicker but there are limits to how fast you can go when you need to stay attached to a column the whole way.
But let's say you can solve that problem and get to geosynchronous orbit in reasonable time. Now what? Well if you want to go anywhere you need to accelerate. You need to bring the fuel for that.
Now compare this to an orbital ring. An orbital ring:
- doesn't require any magical materials. The core of it is nothing more than copper or iron cabling;
- will get you get to and from different points on the Earth much faster;
- provide LEO space to live and work on the stationary (relative to the surface of the Earth) platform. At 20 meters wide you're talking ~1 billion square meters of area, which is almost as large as the land area of Los Angeles;
- allows for huge amounts of solar power to be generated and sent to the ground via transmission cables;
- provides you with enough delta-V to escape the Solar System for almost no cost; and
- has significantly more attractive failure modes. If an orbital ring severs it'll likely fly off into space based on inertia. If a space elevator severs part of it is likely to fall to the ground, which would be... bad.
We don't do it because you don't use hyper-expensive mega-engineering to solve mundane problems with easy solutions, like "where do I put my banana peel".
Surely, the cost of storing that type of waste here (on Earth) is very expensive, both from economical perspective and from risk management perspective. It could be very interesting to compare the costs of sending 1kg of nuclear waste into the sun (or out of our solar system, if that makes it cheaper) compared to storing 1kg of nuclear waste anywhere here on Earth, + adding the cost of the infrastructure that is required to actually store and preserve that waste, + adding the cost of people that are required to protect that infrastructure (a facility of some sort), etc...
Why don't we discuss this easy disposal option seriously? Why do we instead ask seriously about launching it into the sun instead?
Because nuclear waste has been politicized to such an extent that most people have no idea what it is composed of, what the halflifes of its constituents are, how radioactive it is, how chemically reactive it is or even what state of matter it is in. But everyone knows that, like, it is, like, totally dangerous!
Breaking that down to it's constituent protons and neutrons would make it harmless right? Though I have no idea how much energy that would cost, only that the lower bound is probably well above what is reasonable.