If you like it you should put an orbital ring on it

General
1

Regarding the topic of mass surface-to-orbit transport I’ve seen three main types in the Eldraeverse - standard launch vehicles for soft cargo and people, mass-driver / laser-launch hybrids for more durable cargo, and space elevators for both types, but only if the throughput needs to be ridiculous.

What I haven’t seen though are orbital rings, which by all accounts should absolutely flatten space elevators in terms of throughput, and would seem perfect for one of the Core Worlds. Is there an in-universe reason why no-one seems to use them, or have we just not heard about them yet?

2

Just t’be clear, you’re specifically talking about the LEO-used-as-launch-accelerators (although that’s orbit->system, not surface->orbit) type of orbital rings, rather than the simple “we kept building outward from the orbital elevators until the extensions met each other” extended-space-station type of orbital ring?

3

Yeah, the former not the latter

Not true, if you drop short stationary tethers from a low-orbit ring down to the surface, held up by centrifugal force of the ring, then you can reach orbital altitude and exchange momentum with the ring in order to reach orbital / escape speeds. This is a big part of why they out-perform space elevators, at any location along the ring someone who’s ascended the tether can do a maglev braking on the ring itself, and speed up to any speed of their choosing at low-orbit altitude, you don’t have to bother with cars going up and down to one single orbital altitude, and the material requirements for construction are much more benign as well.

4

Oh, those. Right. Well, several reasons:

1. Low orbit is full.

By the time you could build this thing, low orbit is packed full of satellites and stations who do not appreciate having to deal with all this dangly crap passing through their orbits and raising their insurance premia. And since they’re already there, they have priority.

(This is a big enough pain in the rights and liability ass for space elevators, and they at least are single-point objects that are statically stable, and won’t rip through all lower orbits like a buzzsaw if the mechanism driving them in the direction opposite to the ring cable decides to jam one day.)

2. High orbit is full.

By the time you could build this thing, high orbit is also packed full of satellites and stations who do not appreciate having hyperaccelerated outbound traffic - specifically, whose capacity to maneuver independently does not match up to their borrowed velocity - passing through their orbits and raising their insurance premia. And since they’re also already there, they have priority.

3. For the same reason as people aren’t keen on Lofstrom loops or space fountains either.

Because they’re dynamically unstable, i.e., if they stop working even for a moment, they fall right out of the sky. This is not, in general, a desirable property for a megastructure, and it’s a particularly undesirable property for the liability carrier for the megastructure consortium.

4. There’s a lot of cargo, but not usually that much cargo.

Seranth is the Imperial world with the most traffic - probably the world in the Worlds with the most traffic - which it handles just fine with six orbital elevators and a ring station.

(Because when it comes down to it, manufacturing soon stops being something you want to do on planets, because you have to start worrying about environmental externalities and planetary heat budgets and other irritating things.)

It’s still a lot of cargo in its own right, but interface cargo’s a relatively small fraction of the total in any developed system.

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5

Side note:

you don’t have to bother with cars going up and down to one single orbital altitude

It’s not like you can’t hop off an orbital elevator at intermediate stops. Most “Imperial standard” designs have at least four major developed levels, not counting the ground anchor, and the owners would be perfectly happy to sell you basing rights on any of the service platforms if you absolutely have to have a spacedock at that precise altitude. Subject to operational and safety considerations, of course.

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6

Coming through with the world-building as always hehe; I’ll answer in sequence.

Fair enough, consider me guilty of comparing these solutions in a vacuum without regard to developmental history.

Same as 1, although I’m now curious as to how low-orbit traffic is supposed to make its way out-system. Is it a tortuous series of kilometer-high Hohmann transfers until it makes its way into less congested volumes?

This one is strange, because I distinctly remember an article about skypiercer buildings where active support was mentioned in a way that gave me the impression that it was a commonplace construction technique. Is it just a matter of scale then?

Think this one is the one where I went mostly astray; consider me guilty of solving for a problem that doesn’t need to exist. I guess nowhere would you really need to send that much mass upwell unless you were dismantling or mining the planet.

7

Like this: The Shipping Trade (3): Outbound | The Associated Worlds (eldraeverse.com). Like aircraft picking their way out of European airports, you take it easy and you move from slot to slot on your way out the door, because you’re moving through a crowd. Lots of KE and damage potential packed into a tight space encourages great care and attention.

But the real problem is in the whose capacity to maneuver independently does not match up to their borrowed velocity . Orbital space is crowded, but things in it can, by and large, maneuver in ways useful relative to typical orbital speed. (In system space you’ve got dead-stick cargo moving from flinger to flinger, but you’ve also got much more breathing room.)

Even though a ship that’s picked up its outbound momentum from the orbital ring isn’t technically dead-stick, it’s moving at system - i.e., higher than orbital - speeds in orbital space without that consonant ability/Δv to maneuver. No-one likes that.

I may have shortened that answer too much. Basically, you need to provide your liability carrier with evidence of sufficiently cunning safety systems that your structure will not collapse in such a way as to create a very expensive mass-casualty event, such as the ability in that building scenario to safely self-disassemble, seal, and abort to orbit.

So, yeah, scale, because this scales, shall we say, non-linearly.

For one contributory element, consider that skyscrapers mostly just fall down in not all that much more than their own volume. An orbital ring that suffers an uncontrolled structural oopsie develops the various instabilities of a lariat chain or, worst-case. a loose whip, and does so right in the middle of crowded low-orbital space right over your planet.

I can hear the soft weeping of the reliability engineers tasked with turning that into a million-year event from here. :sob:

8

Makes sense, haha! And uh, if you don’t mind me peeking behind the veil, and to paraphrase a great sailor of times past, do you plan this all out, or just make it up as you go along?

9

I plan out as much as possible. Can’t think of everything in advance, obvs., but I prefer to keep pantsing to a minimum.

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