Orbital Rings

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]: ▶ this video

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

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]: ▶ this video

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]: ▶ this video

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] ▶ this video [Paper] link

Isaac Arthur thinks an orbital ring is a better idea: ▶ this 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).

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

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]: ▶ this video

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

> 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]: ▶ this video

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]: ▶ this video

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]: ▶ this video