Orbital Rings

Isaac Arthur4 HN recommenders · 2017–2025
421K views · explainer · evergreen · Uploaded 2017-06-29

Isaac Arthur explains the orbital ring, a megastructure launch-assist system that could move bulk cargo cheaply to orbit and beyond. He compares it with space elevators and discusses power transmission.

HN commenters offer it as the likely future of cheap access to space, feasible without exotic materials.

Watch on YouTube

18 comments from Hacker News

@erasemus2017 · in “Maintenance often matters more than innovation (2016)”

Civilisation is a Red Queen; we must keep running just to stand still. Maintaining and conserving things is the job of conservatives, not entrepreneurs, and conservatives resist change. Indeed most changes are detrimental. Yet in the long run we absolutely depend on change in order to adapt and survive. Therefore there has to be a rigorous way of reconciling these two principles. Without fudging ('maintenance often matters more...') Maybe: visionaries will develop new ideas with no intention to enact them . Eventually a few will become so well-thought-out, so vivid and so blatantly superior to the incumbent alternatives that they become inevitable. That is, society cannot help but enact them. This already seems to be happening in some areas: e.g. moral improvements which come about via fiction, especially fantasy fiction e.g. individual decision-making (it seems like we deliberate for a while and then actions take place automatically) e.g. Project Hieroglyph (no idea how this is getting along but what a great idea) [LINK] ...and of course all those brilliant videos on YT of engineering schemes for the future, e.g. [VIDEO]

@stephengillie2018 · in “France approves 720MW of solar as price falls another 5%”

Electricity transmission would be a foundational part of an orbital ring around Earth. And around a dynamo like Uranus, it could be used to generate electricity too. This (long) video about orbital rings brings such things to mind. [VIDEO]

@mtgx2018 · in “Japan starts space elevator experiments”

Isaac Arthur thinks an orbital ring is a better idea: [VIDEO] He has other videos on ways we could get into space more cheaply, including by space elevators (which he basically doesn't think are feasible).

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@cletus2018 · in “Ask HN: What can be done to prevent a climate catastrophe?”

The likely end result of orbital systems looks something like this: [VIDEO] The thing about the that is that it's not high tech. It's an engineering problem not a science problem. A massive engineering solution I'll grant you. I'll also concede that there are going to be a lot of steps on between.

@mLuby2019 · in “A Lunar Space Elevator Is Feasible and Inexpensive, Scientists Find”

Lot of talk about how 1. a Moon elevator is pointless without an Earth elevator, and 2. we can't build an Earth elevator with today's technology. However we can build an orbital ring around Earth with today's technology, and it'd be much better than space elevators. [Video] [VIDEO] [Paper] [LINK]

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@K0SM0S2019 · in “NASA aims for first manned SpaceX mission in first-quarter 2020”

This is totally right. You might really like Isaac Arthur on YouTube if you don't know him already. "Orbital rings" [1] in his "Upward Bound" series might be just right your alley. Of course, there's so much more he produced, it's even hard to keep up. I personally dream of some "Megastructures" he suggests... Actually already began myself to think of a Dyson Swarm around Earth (for starters) which could then serve as a positional basis for future orbital rings. He really inspired me to think bigger, now. [1]: [VIDEO]

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@cletus2020 · in “Why We Don't Shoot Earth's Garbage into the Sun (2019)”

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. [1]: [LINK] [2]: [VIDEO]

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@cletus2021 · in “The world must cooperate to avoid colliding satellites and space debris”

Here's what I've learned: there is zero chance of the world uniting behind any cause. The solution to any of these problems will be economic and out of necessity and never because of altruism. Want to reduce fossil fuel usage? It'll only happen when cleaner alternatives are cheaper. Climate change? Nothing will change here until there's an economic reason for carbon sequestration. This may seem depressing but there's an important lesson here: any sense of urgency is almost always overblown. Things really do have a way of resolving themselves. Oh and as for space debris, yes it's a problem but space is also really big. Like the US also put a bunch of copper up in space [1] that's still there. How could this resolve itself? It'll end up resolving itself when launch costs are sufficiently cheap. We've made a ton of progress in the last few decades. IIRC SpaceX cost of getting payloads into LEO is like 20x cheaper than 20 years ago but it's still north of $1000/kg. But what does the situation look like when the cost gets below $10/kg? That's not as unrealistic as you may think. A lot of attention is given to space elevators. I think these are likely infeasible (eg they rely on discovering a sufficiently strong material that doesn't exist yet). But orbital rings [2]? These require no magical material and would be completely game-changing. If you have something like that just hang things off them to pick up passing space debris. [1]: [LINK] [2]: [VIDEO]

@cletus2021 · in “Steve Wozniak announces private space company to clean up space debris in orbit”

So here's a potential business model for this: salvage rights. When ships sink, the owner generally still retains ownership of any property. Sometimes the location of the wreck is known. Sometimes it needs to be found. It can cost a lot of money to find a wreck and recover any property. So salvage rights are a principle of maritime law such that whoever does this is entitled to a reward commensurate with the value of the goods recovered (eg 10%). I imagine there are orbital slots that are essentially unusable because of space debris (eg Project West Ford [1]). If orbital slots are sufficiently scarce then these could have value. At some point it may become commercial to spend the effort cleaning up an orbit and making it available. Companies could then be compensated for the value they create this way. I do believe this will still require a dramatic decrease in launch costs, as in orders of magnitude more. But we'll see. My personal belief (and hope) is that the future of getting into orbit is orbital rings [2]. If so, that completely changes the game because cleaning up an orbit essentially becomes a problem of just holding up a giant "paddle" (for lack of a better word) that is fixed to a point on Earth (essentially) and just letting the debris hit it. [1]: [LINK] [2]: [VIDEO]

@cletus2021 · in “Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab”

So during the Space Shuttle (and earlier) era I believe the cost of getting payloads to LEO was $20-50k/kg. Currently with Falcon 9 it's gone down to ~$1000/kg. I imagine this will continue to get cheaper with further reuse and Starship. But we really need to get down to <$10/kg. Thing is, that's entirely achievable. I believe the ultimate future here will be orbital rings [1]. Space elevators get a lot more attention and they really shouldn't because they're a lot less achievable and they require materials we haven't invented yet (to resist the centrifugal force). Imagine being able to take a cable car into orbit. That's what orbital rings promise and you need little more than copper wire and stainless steel. Not only would this bootstrap colonization of space but you can simply attach collectors to the ring itself and run the power down a cable to the ground so you don't even need to suffer the power loss from wireless transmission (which, for the record, is a practical method still). [1]: [VIDEO]

@jmyeet2022 · in “SpaceX’s monstrous, dirt-cheap Starship may transform space travel”

Yes I meant $10m. Sign me up for $10 launches. Interestingly there are proposed launch systems that, while not being $10, would potentially be under $1000 and transform passenger and freight movement on Earth too. I am of course talking about orbital rings [1]. [1]: [VIDEO]

@cletus2022 · in “Impulse Space is betting on a future where launch is cheap”

For another view on how this will change things, consider the delta-V map of the Solar System [1]. As an example you need 45km/s to reach Saturn, roughly 20% of that is just spent getting to Low Earth Orbit. Now consider the long-term trend in the payload cost (by weight) of getting to LEO [2]. This is why people such as myself are so bullish on spaceX (despite quite reasonable qualms about Elon Musk as a person). The impact this has had and will continue to have on reducing this number cannot be overstated. But all of this are still interim steps and we can potentially get the payload to LEO cost under $10/kg. If you want to go down the rabbit hole of this, I strongly recommend Isaac Arthur's Upward Bound series [3], I consider the ultimate end to this to be Orbital Rings [4]. Even if you don't believe there's a reason for humans to go to space en masse (which I disagree with), this will greatly impact life on earth, for example with space-based solar power collectors. [1]: [LINK] [2]: [LINK] [3]: [LINK] [4]: [VIDEO]

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@cletus2022 · in “Space-based solar power is getting serious”

Here is my hope (and my belief): the ultimate end here is orbital rings [1]. To summarize the video, you can put copper cabling in orbit, run a current through it and keep things in place (relative to a point on Earth) with magnetic levitation. The most important part of this is that you can have things in LEO that are fixed to Earth points. Why does this matter? No longer do you have to speed up to Mach 30 to reach orbital speeds. You could technically run a cable from 150km up and carry people and goods from Earth into LEO and back. This could revolutionize long-distance travel on Earth too. It's estimated that a space-based power collector could create about ~7 times the energy of an Earth based collector due to less power loss from the atmosphere and night (to be clear, a solar collector in orbit would still occasionally be occluded by the Earth but it won't be half the time). You can get power down to Earth in two ways: you can transmit it. This is actually viable but is not ideal. Alternatively, if you have an orbital ring, you can attach it to that and just run cables down to Earth. We use longer power transmission lines than that on Earth already. All of this requires no new physics, no magical materials (eg space elevators do) and are just (admittedly massive) engineering projects. If you can get solar panels into orbit for <$10/kg payload costs and run cables down to Earth, you'll solve the variance issue with solar and create cheap power on a massive scale. And non

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@jmyeet2023 · in “Caltech to Launch Space Solar Power Technology Demo into Orbit”

I encourage you to watch The Future of Solar Power [1]. I am firmly of the belief that solar power is humanity's future of energy production. Yes, beaming power to Earth is viable and could be economical. This pretty much solves the problem in variable power generation. I've seen estimates that a space-based power collector could generate about 6-8x what that same collector could on Earth (due to atmosphere, weather and day/night) so even with some power loss from beaming power to Earth, it's viable. But there's an even better fguture for this. The first is as the power source for space habitats. You literally just put them on the outside hull. These are incredibly efficient in creating living area per unit mass and ultimately would become a Dyson Swarm. I consider this inevitable. The second is you can do better than beaming power with orbital rings [2]. In short, you put a loop of conducting cables in orbit, run a current through them and float things on top with the magnetic field. The beauty of this is those things elevated on the ring are fixed to points on Earth. This means you don't need to speed up to Mach 30 to reach orbital speeds. If you have an orbital ring, you can run cables down from space directly to the ground. [1]: [LINK] [2]: [VIDEO]

@cletus2024 · in “Seven Dyson Sphere Candidates”

There are several possibilities here. First, the Earth already receives a ton of energy from the Sun that is "wasted". We estimate that at about 10^16 Watts of power, compared to humanity's energy usage, estimated at 10^10-10^11 watts. So Earth has a ton of energy dissipiation "built in" that we're not "using". Second, there is some inefficiency and thus heat dissipation in converting solar output into usable energy. Doing that in space means a bunch of heat dissipation happens in space rather than on your planet. Third, it's relatively straightforwward to counter any increased heat dissipation on your planet by reducing that solar output that hits your planet. How? You build something at the EArth-Sun L1 Lagrange point. Reducing that solar output that hits the EArth by 1% would likely be unnoticeable to us but could cool the Earth significantly. Also, what do you build there? Well, lots of things. More orbitals, solar power collectors, etc. Fourth, how do you get power down to a planet? There are several candidates. One is to beam it down. This adds a conversion cost. But here's another: you build a n orbital ring [1] 100-150km above the EArth's surface. There are a ton of reasons you'd want to do this: interplanetary travel, cheap travel to and from LEO and easier travel across the planet (ie up to the ring, down to another point on Earth on cable cars, basically). But consider this: it gives you a rigid structure to attach solar power collectors to and you can run power tr

@cletus2024 · in “Seven Dyson Sphere Candidates”

> You don't have a way how to transfer power from Dyson swarm without absurdly staggering losses. Why do you need to transfer power? The point of an orbital is primarily for people to live on. A single orbital could potentially support a million or more people. Are you referring to the issue of providing power to Earth? That's... a separate issue, with different solutions. The idea of power satellites [1] has had a lot of thought. An alternative approach is to build an orbital ring [2] and hang solar power collectors off of it. You could this power directly to the ground with transmission lines. > Dyson swarm satellite would be heated up by incoming heat from Sun on one side An orbital would be heated on the side facing the Sun and radiate away heat away when not facing the Sun in the exact same way that the Moon is scorching hot when facing the Sun and 200 below zero when not. [1]: [LINK] [2]: [VIDEO]

@jmyeet2025 · in “Space Elevator”

Space elevators aren't going to happen. Not in Earth's gravity well anyway. Even if you can find a material strong enough (and that's a big "if"), you still have to traverse 50,000km to get from Earth's surface to geosynchronous orbit to get the benefit. You know what does make way more sense and is way more achievable? Orbital rings [1]. Basically, put some copper wire in space, orbit it at ~8km/s, run a current through it and then you can reset structures on top of it (magnetically) and those structures are fixed to the Earth's surface . You can technically run a cable from 100-150km up to the surface and run a gondola into LEO. This would transform both Earth transport and interplanetary travel. You accelerate something on the inside (Earthside) of the ring at ~2G, like with a maglev train, and you have enough velocity to escape the Solar System. [1]: [VIDEO]

@jmyeet2025 · in “Voyager 1 is a light-day away by November 2026”

I remember as a kid seeing the first photos of Uranus and Neptune from the Voyager probes. What's sad to me is they remain to this day the only time we've ever visited these ice giants. There have been a number of proposals over the years but none have been selected and it seems like 2045-2050 is the soonest we could get to Uranus (more for Neptune) but that pretty much requires a launch by 2034 and we've pretty much run out of time for a mission to be selected to that window given that it would be a complex and expensive flagship mission. I guess it depends on whether it's a flyby (like New Horizons) or an intercept mission, which would take substantially longer. Obital mechanics are a funny thing however. You see this with the complicated BepiColombo trajectory to Mercury [1] that requires multiple passes on Venus. Mercury orbits at ~48km/s (compared to Earth's 30km/s). Fun fact: the escape velocity of the Sun is 42km/s so it's easier to leave the Solar System than intercept Mercury. One difficulty is there aren't large gas giants to slingshot or brake around. Uranus's orbital velocity is ~6.8km/s so it's both really far and requires a ton of delta-V to slow down to intercept. Anyway, I digress. So Voyager 1's speed seems to be ~17km/s, I guess relative to the Sun. People talk about the time required for interplanetary (let alone interstellar) travel but we can do much better than this with relatively near-future technology. We need a whole bunch more Earth-orbit space infr