However, there are quasi-stable positions slightly sunward of L1 where you can balance these instabilities and actually use the solar sail effect for station keeping in a swarm. It would require launching a lot of rockets, but is entirely doable with today’s technology.
Not a scientist, but I’m still fascinated by this stuff.
The cost of that is going to be the big issue. No government is going to want to pay for routine shipments of fuel and parts to L1, which is expensive as hell. And I wouldn’t bet on international cooperation being a thing either. Each country is going to be too busy fighting over food and water, and keeping migration at bay.
Completely guessing here, it would probably be cheaper to raise the albedo of the planet through various means. Maybe including massive scale cloud seeding over the oceans. At least it’s on planet and therefore hypothetically can be done with minimal fossil fuel use. How to do that without fucking up the environment with chemicals for cloud nuclei is the hard part.
That, or intentionally inducing a light nuclear winter, ideally without the nuclear part. With enough particulates in the upper atmosphere, it would do the job. The tricky part is doing that without overdoing it. This is the dumb version, but it’s personally how I see things going. Especially because this is something a lone country could probably do on its own. China doesn’t want to deal with all the effects of climate change? They may light up a bunch of islands in the Pacific with nukes to “solve” it.
Another dumb option that might arise, a country intentionally trying to start another global pandemic to reduce emissions. Emissions dropped dlike a rock with COVID, and a lot of countries have the ability to produce bioweapons.
There are myriad of dumb, harmful, cheap ways that individual countries could use to curb climate change. The next few decades are going to be dangerous as hell.
Engagement, huzzah! Okay, the funding issue is an issue. Ironically, it requires companies like SpaceX (or their competition as they come online) to get the launch prices down. It’s doable though. Back of envelope: The largest solar sail launched so far has been a paltry 14x14m, if my memory serves correctly. In order to reduce the incoming sunlight by 0.1%, you would need something like 60x1000 km of solar sails. Assuming you can make them 1 sq km each, you’re looking at 60k solar sails. But they can be very very lightweight. Wikipedia proposes 0.02 g/m2 as a lower limit… let’s use 0.05 g/m2 so we have some leeway and don’t need exotic materials. Thus a 1km2 solar sail would weigh only 50kg (of sail material). Add another 200kg for some tensile frame and some control electronics and you’re looking at something like a Starlink mass to get 1km2. Sure you’d need 60k of these things, but launching Starlink swarms that size is doable (to LEO – you’d need a bigger rocket than the F9 for L1). Let’s suppose Starship (or similar) is launching them in batches of 60 for $10M/launch… That’s 1000 launches. Currently SpaceX is launching about every three days, so assuming Starship is online and capable, that would be three years of launches at the same rate as Starlink (but with a bigger rocket) and ten billion dollars. Okay, even if costs go up by an order of magnitude, we can do this, now, today, for about the cost of purchasing twitter. Musk really fucked up didn’t he ;)
Okay, that’s a lot of methane to launch the rockets. Back of the envelope, assuming one launch uses ~300t of methane. The per capita use of natural gas (globally) is about 50 cubic feet per person per day. A cubic foot of natural gas is about 35 grams, so the per capita usage in mass is about 1750g/day/person. So a single rocket launch uses about the same amount of natural gas 171,428 people would for one day. It’s actually very small, comparatively. Even if I got my estimates wrong by two orders of magnitude (on total number of launches), it’s still very small compared to the total amount of gas burned globally every day.
Okay, other options: we put the solar sails in a very high earth orbit (above the comms satellites) – doable, but you’ll require many many more of them as they won’t site between the Earth and the Sun during most of their orbit. LEO would cause problems with collisions with comms satellites. You can’t put them very low due to atmospheric drag. Plus, the closer they are, the more likely they are to create where little eclipses as their shadows pass by. L1 really is probably the best option.
Blimps flying around could do it. But you’d need like 60k blimps flying around in the upper atmosphere and each blimp would have to be an engineering marvel to get to that size. Probably not doable.
There’s cloud seeding, as you suggest. But that becomes a political hot potato (blimps would too) due to where the clouds are created. What if China seeded some clouds which cause a torrential rainfall and flooding in Mexico as the atmospheric currents move those clouds. Etc.
A light nuclear winter sounds like a disaster – what do we do, nuke a few volcanoes to set them off prematurely? That doesn’t sound sustainable. Burn all the forests to release ash? Nope, that’s our carbon sink that’s burning…
Ironically, raising our albedo might be a decent local option – just mandate white roofs everywhere. Just under 3% of our surface is urban and white roofs would also help with the urban heat island issue. You can probably paint 0.2% of the surface white. Not as good as blocking sunlight, but useful. The bad part is, solar panels are all dark, and moving to solar decreases our albedo. So maybe this will just offset changes in our average albedo due to solar panels.
There’s cloud seeding … What if China seeded some clouds which cause a torrential rainfall and flooding in Mexico
Or the exact opposite: what if China is successful? Cloud seeding doesn’t change the amount of moisture in the air, only where it falls. If you do succeed in getting it to fall prematurely, that means it’s not going to fall where it would otherwise have.
Any earthbound intervention is likely to be similar: even if you’re successful in modifying local weather, you’ve also modified someone else’s weather, and likely not for the better
Huzzah! Forewarning, I’m gonna be building off of your napkin math, because napkin rocket science math is fun.
it requires companies like SpaceX (or their competition as they come online) to get the launch prices down.
Absolutely. Given the scale of such a project like this, the price per launch would absolutely go down over time (assuming no bullshitery on SpaceX/other corporate entity’s part.) Though your original price point of $10m/launch is a bit off. The Falcon Heavy for instance, costs roughly $60-90m depending on payload and destination, and whether or not the rocket is recovered.
Thus a 1km2 solar sail would weigh only 50kg (of sail material). Add another 200kg for some tensile frame and some control electronics and you’re looking at something like a Starlink mass to get 1km2.
Another way to get an estimate is to compare to a recent, modern launch. The JWST is a good comparison, especially since it is in a similar orbit/distance/mission. The whole thing weighs 6,500kg, with 350kg of that being the RCS/reaction wheels/comms/electronics/frame/etc all wrapped up in the spacecraft bus.
So a completed frame can reasonably have a payload of 6,150kg for solar umbrella activities. If we put 1/3rd of that into the umbrella frame and the rest into the umbrella material, that’s 4100kg for sail material, or 82km2. How you’re gonna built an extendable frame that extends into a 9km x 9km sheet is a challenge, but maybe surmountable. This is a significantly bigger scale than the 1km2 sats you’ve proposed, but if the weight allocation works with JWST something similar should work here. The solar pressure will increase the fuel needed to keep a stable orbit, but nothing that our pre-designed launch platform can’t handle.
So that would be 731 of these JWST scale sats that need to be put into L1 orbit. JWST was launched with the Ariane 5, which costs $150-200m/launch. That’s significantly more that then $10m/launch, but getting all the way out to L1 with a 6,500kg payload is hard. I wasn’t able to find a cost associated with the JWST itself, only the development cost of ~$8.8 billion. But I’m gonna assume that the construction of the satellite itself was in the millions, if not billions. If it is even a single billion for just one of these, that’s almost a trillion dollars for this project as a whole.
All of that for only a 0.1% reduction in sunlight. Not sure how much we need, but it seems small.
Okay, other options: we put the solar sails in a very high earth orbit (above the comms satellites) – doable, but you’ll require many many more of them as they won’t site between the Earth and the Sun during most of their orbit.
I have an even dumber, even more harmful, version of this that is just as fun to explore. Go up to the moon, build a couple rail launchers, and start launching shit loads of moon regolith into a high orbit around the earth, somewhere between geostationary orbit and lunar orbit. Eventually Earth will have it’s own set of rings. We only launch everything for one week of the month every month to ensure the inclination of the rings stays somewhat uniform.
The benefit of this being once the infrastructure to do this is put on the moon, this can essentially run for free forever. We just have to be mindful of avoiding Earth’s rings as we travel outside of our system.
Ironically, raising our albedo might be a decent local option – just mandate white roofs everywhere. Just under 3% of our surface is urban and white roofs would also help with the urban heat island issue. You can probably paint 0.2% of the surface white. Not as good as blocking sunlight, but useful. The bad part is, solar panels are all dark, and moving to solar decreases our albedo. So maybe this will just offset changes in our average albedo due to solar panels.
I think this is an almost guaranteed partial solution that we will end up doing. If you’ve traveled around at all, you’ll notice that hotter climates tend to use white roofs, seemingly automatically. Home owners will automatically do whatever suits them for the climate, no matter how the climate changes. The problem here is so much of our buildings and infrastructure isn’t roofs. So much of it is roads and parking. That’s a lot harder to change the albedo.
A light nuclear winter sounds like a disaster – what do we do, nuke a few volcanoes to set them off prematurely? That doesn’t sound sustainable. Burn all the forests to release ash? Nope, that’s our carbon sink that’s burning…
Your last option reminds me of: Kill all the poor!
Yeah, these are the dumbest, most harmful solutions. But they’re also probably the cheapest, which is why they’re so scary. All it takes is one or two rogue states seeing this as a viable option, and it might end up happening.
No government is going to want to pay for routine shipments of fuel and parts to L1
There should be no need, no point. Actual repairs would be too costly way out there, plus we’d have to have a large cluster of shades where losing one doesn’t matter.
hopefully they can be mostly solar powered, greatly extending fuel supply
just send more. Actually, that’s the cost: routinely send more
Solar sailing doesn’t require fuel, and can be truly solar powered. The IKAROS probe is a great example of this, and it was launched quite a while ago already. My favourite part of this probe was the liquid crystal panels that could change brightness and darkness electrically in order to steer by creating a differential absorption/reflection of sunlight. Clever stuff. It’s basically a steerable continuous thrust system that tacks against sunlight.
Probably you’d still want some RCS thrusters for faster reaction times in a pinch. And reaction wheels are “free” in terms of fuel, so there is likely some upper bound to lifetime. But not as bad as normal spacecraft.
Long short: RCS thrusters are probably still useful, but may not necessarily need to be the primary means of station keeping.
Clever stuff. It’s basically a steerable continuous thrust system that tacks against sunlight.
Very clever, and very useful. Though probably not useful for this case. The solar pressure/wind will enact a constant normal force on the orbit of any craft at L1. So to maintain stable orbit (from my understanding) you will need to counteract that with a constant antinormal force, or else you’ll get pushed out of L1 and then go flying off.
I know on Earth you can sail more or less directly into the wind with a sail boat using clever geometry, but I’m not so sure that is possible when orbits are involved. That’s the limit of my KSP based knowledge of orbital mechanics lol.
There’s also some untested methods that could potentially work here,
I have to disagree with the first two you listed. The electrodynamic tether would slow down the craft and knock it out of L1 orbit. If I’m understanding, it’s the space equivalent of regenerative breaking. The magnetic sail would esentially have the same problem as the solar sail.
The bussard engine would definitely work, assuming the basic principle of the engine itself works. Though, I’m not sure if it would collect enough hydrogen when placed at L1. A very neat concept though, one I’d like to see happen!
Long short: RCS thrusters are probably still useful, but may not necessarily need to be the primary means of station keeping.
If we’re using today’s technology, they’d almost certainly be the primary means. But in this hypothetical future you may be right.
So to maintain stable orbit (from my understanding) you will need to counteract that with a constant antinormal force, or else you’ll get pushed out of L1 and then go flying off.
You’re absolutely right, assuming the craft is on the L1 saddle point. The craft can, however, sit slightly sunward of the saddle point in a halo orbit. It wants to fall towards the sun (and enter a solar orbit) due to being on that side of L1, but you set it in the position it needs to be to balance the force of sunlight. There will be quasi-stable points in a halo orbits around the sun-facing side of L1 which could sustain a whole lot of these buggers.
KSP is great, but it only does two body physics (unless you’re using the Principia mod – never tried it). So you cannot simulate things like lagrange points there. The patched conics are a great first order teaching tool though, and KSP is great for that!
There will be quasi-stable points in a halo orbits around the sun-facing side of L1 which could sustain a whole lot of these buggers.
I’ll take your word for it then.
KSP is great, but it only does two body physics (unless you’re using the Principia mod – never tried it). So you cannot simulate things like lagrange points there.
Would have been a nice addition to KSP 2 if they hadn’t fucked it up. I’ll check out that mod at some point though.
Not a scientist, but I’m still fascinated by this stuff.
The cost of that is going to be the big issue. No government is going to want to pay for routine shipments of fuel and parts to L1, which is expensive as hell. And I wouldn’t bet on international cooperation being a thing either. Each country is going to be too busy fighting over food and water, and keeping migration at bay.
Completely guessing here, it would probably be cheaper to raise the albedo of the planet through various means. Maybe including massive scale cloud seeding over the oceans. At least it’s on planet and therefore hypothetically can be done with minimal fossil fuel use. How to do that without fucking up the environment with chemicals for cloud nuclei is the hard part.
That, or intentionally inducing a light nuclear winter, ideally without the nuclear part. With enough particulates in the upper atmosphere, it would do the job. The tricky part is doing that without overdoing it. This is the dumb version, but it’s personally how I see things going. Especially because this is something a lone country could probably do on its own. China doesn’t want to deal with all the effects of climate change? They may light up a bunch of islands in the Pacific with nukes to “solve” it.
Another dumb option that might arise, a country intentionally trying to start another global pandemic to reduce emissions. Emissions dropped dlike a rock with COVID, and a lot of countries have the ability to produce bioweapons.
There are myriad of dumb, harmful, cheap ways that individual countries could use to curb climate change. The next few decades are going to be dangerous as hell.
Engagement, huzzah! Okay, the funding issue is an issue. Ironically, it requires companies like SpaceX (or their competition as they come online) to get the launch prices down. It’s doable though. Back of envelope: The largest solar sail launched so far has been a paltry 14x14m, if my memory serves correctly. In order to reduce the incoming sunlight by 0.1%, you would need something like 60x1000 km of solar sails. Assuming you can make them 1 sq km each, you’re looking at 60k solar sails. But they can be very very lightweight. Wikipedia proposes 0.02 g/m2 as a lower limit… let’s use 0.05 g/m2 so we have some leeway and don’t need exotic materials. Thus a 1km2 solar sail would weigh only 50kg (of sail material). Add another 200kg for some tensile frame and some control electronics and you’re looking at something like a Starlink mass to get 1km2. Sure you’d need 60k of these things, but launching Starlink swarms that size is doable (to LEO – you’d need a bigger rocket than the F9 for L1). Let’s suppose Starship (or similar) is launching them in batches of 60 for $10M/launch… That’s 1000 launches. Currently SpaceX is launching about every three days, so assuming Starship is online and capable, that would be three years of launches at the same rate as Starlink (but with a bigger rocket) and ten billion dollars. Okay, even if costs go up by an order of magnitude, we can do this, now, today, for about the cost of purchasing twitter. Musk really fucked up didn’t he ;)
Okay, that’s a lot of methane to launch the rockets. Back of the envelope, assuming one launch uses ~300t of methane. The per capita use of natural gas (globally) is about 50 cubic feet per person per day. A cubic foot of natural gas is about 35 grams, so the per capita usage in mass is about 1750g/day/person. So a single rocket launch uses about the same amount of natural gas 171,428 people would for one day. It’s actually very small, comparatively. Even if I got my estimates wrong by two orders of magnitude (on total number of launches), it’s still very small compared to the total amount of gas burned globally every day.
Okay, other options: we put the solar sails in a very high earth orbit (above the comms satellites) – doable, but you’ll require many many more of them as they won’t site between the Earth and the Sun during most of their orbit. LEO would cause problems with collisions with comms satellites. You can’t put them very low due to atmospheric drag. Plus, the closer they are, the more likely they are to create where little eclipses as their shadows pass by. L1 really is probably the best option.
Blimps flying around could do it. But you’d need like 60k blimps flying around in the upper atmosphere and each blimp would have to be an engineering marvel to get to that size. Probably not doable.
There’s cloud seeding, as you suggest. But that becomes a political hot potato (blimps would too) due to where the clouds are created. What if China seeded some clouds which cause a torrential rainfall and flooding in Mexico as the atmospheric currents move those clouds. Etc.
A light nuclear winter sounds like a disaster – what do we do, nuke a few volcanoes to set them off prematurely? That doesn’t sound sustainable. Burn all the forests to release ash? Nope, that’s our carbon sink that’s burning…
Ironically, raising our albedo might be a decent local option – just mandate white roofs everywhere. Just under 3% of our surface is urban and white roofs would also help with the urban heat island issue. You can probably paint 0.2% of the surface white. Not as good as blocking sunlight, but useful. The bad part is, solar panels are all dark, and moving to solar decreases our albedo. So maybe this will just offset changes in our average albedo due to solar panels.
Your last option reminds me of: Kill all the poor!
Or the exact opposite: what if China is successful? Cloud seeding doesn’t change the amount of moisture in the air, only where it falls. If you do succeed in getting it to fall prematurely, that means it’s not going to fall where it would otherwise have.
Any earthbound intervention is likely to be similar: even if you’re successful in modifying local weather, you’ve also modified someone else’s weather, and likely not for the better
Humans have gone to war for less
Right – cause rain to fall here, cause a drought elsewhere. Etc. Could probably be weaponised if clever about it.
Huzzah! Forewarning, I’m gonna be building off of your napkin math, because napkin rocket science math is fun.
Absolutely. Given the scale of such a project like this, the price per launch would absolutely go down over time (assuming no bullshitery on SpaceX/other corporate entity’s part.) Though your original price point of $10m/launch is a bit off. The Falcon Heavy for instance, costs roughly $60-90m depending on payload and destination, and whether or not the rocket is recovered.
Another way to get an estimate is to compare to a recent, modern launch. The JWST is a good comparison, especially since it is in a similar orbit/distance/mission. The whole thing weighs 6,500kg, with 350kg of that being the RCS/reaction wheels/comms/electronics/frame/etc all wrapped up in the spacecraft bus.
So a completed frame can reasonably have a payload of 6,150kg for solar umbrella activities. If we put 1/3rd of that into the umbrella frame and the rest into the umbrella material, that’s 4100kg for sail material, or 82km2. How you’re gonna built an extendable frame that extends into a 9km x 9km sheet is a challenge, but maybe surmountable. This is a significantly bigger scale than the 1km2 sats you’ve proposed, but if the weight allocation works with JWST something similar should work here. The solar pressure will increase the fuel needed to keep a stable orbit, but nothing that our pre-designed launch platform can’t handle.
So that would be 731 of these JWST scale sats that need to be put into L1 orbit. JWST was launched with the Ariane 5, which costs $150-200m/launch. That’s significantly more that then $10m/launch, but getting all the way out to L1 with a 6,500kg payload is hard. I wasn’t able to find a cost associated with the JWST itself, only the development cost of ~$8.8 billion. But I’m gonna assume that the construction of the satellite itself was in the millions, if not billions. If it is even a single billion for just one of these, that’s almost a trillion dollars for this project as a whole.
All of that for only a 0.1% reduction in sunlight. Not sure how much we need, but it seems small.
I have an even dumber, even more harmful, version of this that is just as fun to explore. Go up to the moon, build a couple rail launchers, and start launching shit loads of moon regolith into a high orbit around the earth, somewhere between geostationary orbit and lunar orbit. Eventually Earth will have it’s own set of rings. We only launch everything for one week of the month every month to ensure the inclination of the rings stays somewhat uniform.
The benefit of this being once the infrastructure to do this is put on the moon, this can essentially run for free forever. We just have to be mindful of avoiding Earth’s rings as we travel outside of our system.
I think this is an almost guaranteed partial solution that we will end up doing. If you’ve traveled around at all, you’ll notice that hotter climates tend to use white roofs, seemingly automatically. Home owners will automatically do whatever suits them for the climate, no matter how the climate changes. The problem here is so much of our buildings and infrastructure isn’t roofs. So much of it is roads and parking. That’s a lot harder to change the albedo.
Yeah, these are the dumbest, most harmful solutions. But they’re also probably the cheapest, which is why they’re so scary. All it takes is one or two rogue states seeing this as a viable option, and it might end up happening.
There should be no need, no point. Actual repairs would be too costly way out there, plus we’d have to have a large cluster of shades where losing one doesn’t matter.
That only works with ion thrusters, which are extremely expensive IIRC. But even they need fuel.
Most satellites that are that far out still use RCS thrusters with reaction wheels. But solar power only helps so much with that.
That’s gonna get costly very quickly. I doubt there is the political will to do this.
Solar sailing doesn’t require fuel, and can be truly solar powered. The IKAROS probe is a great example of this, and it was launched quite a while ago already. My favourite part of this probe was the liquid crystal panels that could change brightness and darkness electrically in order to steer by creating a differential absorption/reflection of sunlight. Clever stuff. It’s basically a steerable continuous thrust system that tacks against sunlight.
There’s also some untested methods that could potentially work here, like eletric tethers in the sun’s magnetic field – this stuff: https://en.wikipedia.org/wiki/Electrodynamic_tether – although I’m not aware of anyone that has done this calculation in the context of sunshields. And further outside the box, magnetic sails: https://en.wikipedia.org/wiki/Magnetic_sail or even this craziness https://en.wikipedia.org/wiki/Bussard_ramjet#Dyson_swarm-based_stellar_engine_(Caplan_thruster)
Probably you’d still want some RCS thrusters for faster reaction times in a pinch. And reaction wheels are “free” in terms of fuel, so there is likely some upper bound to lifetime. But not as bad as normal spacecraft.
Long short: RCS thrusters are probably still useful, but may not necessarily need to be the primary means of station keeping.
Very clever, and very useful. Though probably not useful for this case. The solar pressure/wind will enact a constant normal force on the orbit of any craft at L1. So to maintain stable orbit (from my understanding) you will need to counteract that with a constant antinormal force, or else you’ll get pushed out of L1 and then go flying off.
I know on Earth you can sail more or less directly into the wind with a sail boat using clever geometry, but I’m not so sure that is possible when orbits are involved. That’s the limit of my KSP based knowledge of orbital mechanics lol.
I have to disagree with the first two you listed. The electrodynamic tether would slow down the craft and knock it out of L1 orbit. If I’m understanding, it’s the space equivalent of regenerative breaking. The magnetic sail would esentially have the same problem as the solar sail.
The bussard engine would definitely work, assuming the basic principle of the engine itself works. Though, I’m not sure if it would collect enough hydrogen when placed at L1. A very neat concept though, one I’d like to see happen!
If we’re using today’s technology, they’d almost certainly be the primary means. But in this hypothetical future you may be right.
You’re absolutely right, assuming the craft is on the L1 saddle point. The craft can, however, sit slightly sunward of the saddle point in a halo orbit. It wants to fall towards the sun (and enter a solar orbit) due to being on that side of L1, but you set it in the position it needs to be to balance the force of sunlight. There will be quasi-stable points in a halo orbits around the sun-facing side of L1 which could sustain a whole lot of these buggers.
KSP is great, but it only does two body physics (unless you’re using the Principia mod – never tried it). So you cannot simulate things like lagrange points there. The patched conics are a great first order teaching tool though, and KSP is great for that!
I’ll take your word for it then.
Would have been a nice addition to KSP 2 if they hadn’t fucked it up. I’ll check out that mod at some point though.