FULL SIZE IMAGE
Talita is very excited to explain to you how the local megastructures work!
Reminder to get your questions in for the character AMAs (submit questions here). As I said I will probably do AMA responses for 2 weeks because I am hoping to finish chapter 6 pages by the end of this year, and thus stay about 3 chapters ahead of the pages on this website. For now, at least. I have attempted to time the release of pages on here to be done around the same time I am done drawing the book, so it'll slowly catch up to me the entire time. This is fine, sometimes I need to light a fire under my ass to get work done.
Transcript
LOG 3.1: The Launch Loop
Talita: The launch loop is an active structure maglev cable transport system. The upper rail is held 80 kilometers above Dirtball's surface by the momentum of dozens of rotor belts that circulate through the structure. The circulation transfers the weight of the structure onto magnetic bearings at the grounded ends, which support it.
Diagram of the end of the launch loop:
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30 km wide rail loop
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radio dome
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berm wall surrounding rail loop
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magnetic bearings attached on each side of loop
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loop access rails
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ground access rail
Talita: In total, it's about 2,700 kilometers long and 80 kilometers tall, and the support rail width is about 60 meters. Quite large!
Diagram of a cross section of the launch loop rail:
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central maglev rail
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2 maintenance cables and personnel maglev rails below main rail
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7 active support stands
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support rails for stabilizing payload
Diagram of a cross section of an active support strand:
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5 rotors per strand
Talita: This megastructure was created as an upfront investment by a Tiiliitian mining company, and it paid for itself in ease of exporting billions of tons of metals, rare gases, and heavy water.
LOG 3.2: The Skyhook
Orbital Tether
Diagram:
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counterweight
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satellite body
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600 km tether
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The hook, which may be swapped out to pick up different kinds of payloads.
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orbital direction (path around planet)
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spin direction (rotation of the entire structure)
Attachment Process
Diagram:
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payload accelerates on launch loop rail to the speed of the passing attachment point
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both traveling 3,800 m/s relative to surface
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"basket" grapple points extend from hook
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The RCS (reaction control system) positions baskets over “hitch” attachment points on the payload sled.
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basket tightens
Diagram of Dirtball (aka Ixion III, Shikaviil III):
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Path of satellite body: a circular orbit around Dirtball
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Path of hook: A three-lobed path following around the path of the satellite body
Talita: Incoming payloads give some of their kinetic energy to the skyhook, which slows them down enough to be safely transferred to the loop’s rail, and the skyhook uses that borrowed kinetic energy to fling outgoing payloads into higher orbit.
Talita: The skyhook orbits Dirtball about every 2 hours, and the entire structure slowly spins as it does. The 600 kilometer tether extending from the satellite body passes 80 kilometers above the surface at 3 different points, most importantly over the rail of the launch loop. Payloads are put into support sleds with hitch spurs and are sent up the rail of the launch loop to accelerate up to 3,800 meters per second, the speed of the passing skyhook's attachment point.
Idrisah: It's so scary.
Talita: (visibly delighted) Everything in aerospace is!
46 thoughts on “Runaway to the Stars: Page 109 and 110”
Greenjoe
The logistics of how megastructures like this are made is a scary thing too.
Hunter
So, most of the launch loop is just hanging freely in the air while the big magnetic bearings hold it in place to keep it from careening off into the void? Interesting. Guess in near-zero G it’s more cost effective to do that rather than just plant it in the ground with columns.
Apollo235
Actually the gravity on Dirtball is .8g. On Earth a launch loop like that cant be built with traditional or “passive-support structure”, we don’t have anything strong enough to hold it up, considering the reasonably high gravity on Dirtball, the same likely applies. To get around these material limits, the launch loop uses something called an “active-support structure”. If you’ve ever seen a ping-pong ball be held in up by a stream of air, that’s the basic idea. The momentum of the strands holds them up and the tethers anchored to the ground are what keep the top part flat, without them the strands would follow a parabola. So it’s not that it’s cheaper to build a launch loop this way, this is the ONLY way to build one.
ImJustaTourist
“Early on, it was the rocket. In the 2100’s, they added the sky-hook, in the 2200’s there was the space elevator.
Now introducing the launch tech of the future,
Launch Loop!”
cassette lesbian
why is talita so cute‽‽‽‽‽
Ruby
Does it feel like a rollercoaster? I like rollercoasters.
JoB
Do you like rollercoasters where the “train” is *made* to DETACH FROM THE RAILS at max speed, too? :-3
Sen
Lovely details on the mechanics and sciences. The whole thing being kept upright simply by slinging scifi rope through it at high speeds is mind boggling ^^
Paroxysmall
visibly delighted Talita is always a treat! (so is, know, everything else going on here obviously)
even now i still get tripped up over the scale of the launch loop and rail… something so large being designed, built, and used by people, yet even its broken up components look like naturally occurring topography because of their scale
Gar G
I love how Talita looks so happy as she explains this. Nice being able to geek out over your passions like that!^^
goose
How long does it take to land/take off using the skyhook-and-rail? 2700km seems SO long but i’m guessing it helps fling the ships at the power needed
Hunter
In imperial terms it’s 8500.358 miles per hour, but the pace of the payloads is 3800 meters per second on a 2700 kilometer-long loop, that’s roughly 4 kilometers per second, so that’s roughly 675 seconds. So essentially it takes around 25/27? minutes for something to completely go around the launch loop traveling at that speed.
If my math is right.
Hunter
Upon checking myself, roughly 15/17 minutes, give or take.
goose
not too bad, but the force must feel crazy at those speeds!
Red
I love the speculative morphology and Talita has always been adorable. But there is this part of my mind that has absolutely latched on to the idea, ever since I found out that she speaks through what my anthropocentric brain sees as a nose, that when she talks, it’s just emotive kazoo noises and everyone just kinda understands intuitively in the same way that everyone understands R2D2.
Trees
And the Radio Dome must be where they play all the greatest hits.
JoB
[wonders how much the folks in the habitat can *hear* of that, given that there’s the berm *and* the strong magnetic fields of the loop in the way]
Gheesfellow
All aboaaaard the YEET-MOBILE!
Ginkgosauras
FYI on this and the previous double page, the full size image link doesn’t lead to an image which is any higher quality than the one on the website for some reason. IIRC the other double pages we’ve seen so far don’t have this problem. Regardless I love the info log pages, they give so much serotonin!
Jay Eaton
They’ve all been links to the image hosted on the website? The link is there to make it easier to read two-page spreads, since they display in a 900 px or so div element. I am also planning to start downsizing the comic images to 2000 px wide for the two-page spreads and 1000 px wide for the single pages because loading times for this website on sub-optimal internet suck ass.
Ginkgosauras
Noooo 😭 as much as the loading times can suck, I love zooming in on the pages and looking at all the juicy little details. This page is so pixelated, I don’t like to imagine that the rest of the entire comic will be posted in this quality… the loading times are worth it imo (and I’m saying this as someone with sub-optimal internet)
Peter Jensen
Total agreement. Also, unless you do zoom in, a modern browser will only load the lower resolution picture anyway, because of the way several resolutions are presented with srcset. Testing a few pages, it looks like you get a sub-MB picture at neutral zoom on a 1080p monitor, but if you zoom in the browser will eventually load a 4-5MB picture with all the juicy details I love going over on every page. Would be sad to see that go. As for page load speeds in general, it does look like there’s *something* that hangs, but it isn’t the comic image. Might be the page background, since that always seems to pop in last, but could be something else entirely.
evileeyore
Weirdly I’m getting “Oops! That page can’t be found.”
I have the comic from Patreon so I can reread it in all the zoomed in glory, so no worries for me… but for others…
Jay Eaton
The media file was being fucky because I replaced it, hopefully the link is fixed now
Michi
Excellent tech explanation, just needs a banana for scale 🙂
Jay Eaton
Banana is here but not visible do to scale 😌
JoB
Too bad that the rat doesn’t have a matching vacuum suit to stand in the pictures in the banana’s stead …
Truther
600 km? Damm…
Apollo235
I love seeing Talita infodumping about aerospace!! I like to do it too, but I don’t look as cute…
Maia
Oh good you’re talking about active support structures! This is a solid set up too! I love that you showed the actual mechanisms for attaching and detaching loads to the skyhook. A loop and hook set up like this is a relatively cheap way to move megatons of material off an airless world like Dirtball. More populated worlds could use orbital rings to supplement traffic as well, I wouldn’t be surprised if the Bugferret homeworld has a more complex arrangment of loops and rings working in tandem for material transfer. This is a really good illustration, and a good introduction to the conept of active structures and what they might mean wihtout really getting heavy into the specifics. Good work Jay Eaton!
JoB
(There are pictures on the blog showing bug ferret planets with space *elevators*, so I guess that *that’s* their preferred method.)
HAL9000
“everything in aerospace is [scary]” yeah talita i feel you girl… every now and then i think too hard about flight mechanics and go eurghhh i can’t believe this actually works. thats why i love it.
also you have done a great deal of research in here, i feel like i haven’t said anything before but goddamn you put the work in to make this stuff hard scifi and believable enough. for a bio major you’re suprisingly good with engineering
dokki
Ive always been fascinated by the skyhook. Now I get to see it up close!!!!
as a train nerd I think it’s especially cool seeing that even 300+ years in the future, we’re still using rails (modified and nearly unrecognizable) but rails nonetheless
JoB
[imagines trying to *manually* steer a vehicle so as to stay on an 80-km-high bridge at 8500 mph]
[daintily votes “YES rails!!!”]
Sevoris
You get infrastructure and you get infrastructure and you get infrastructure and EVERYBODY GET INFRASTRUCTURE
Launch loops and momentum exchange tethers and propulsion beams are so much *fun*. Roads and rail, not just dirt tracks.
EveryZig314
More excellent Talita faces
Guest
I love it when Talita nerds out!
Claire
I bet fear of skyhook transit is very commonplace, a la fear of air travel.
Ive said this before but it seems relevant now.
creetur
I remember seeing a video on how hypothetical sky hooks could work. Still cool to me, that it could happen in a relatively short amount of time from now.
Also, Talita being a nerd my beloved :]*
Synthaphone
I love how Talita lights up when she’s talking about aerospace!
Translunary_Animus
I’m really glad we get a whole information page on the Skyhook and Launch Loop because honestly I think i’d be totally lost without it! It’s a very cool mechanism but i’m 100% not an engineer so the finer (and not so fine) portions of aerospace engineering tend to be lost on me.
JoB
“It’s so scary!”
Not scary enough to keep you off the planet whose only means of access it apparently is, Idrisah! 😉
So the support structure under the Runaway is indeed one of the support sleds – but minus the hitch spurs that the skyhook would connect to.
“(aka Ixion III, Shikaviil III)”
Ah, so “Shikaviil”‘s the proper name given to the *sun*, not the planet?
atriflemiffed
I think “Ixion” and “Shikaviil” are the human and avian names for the system, respectively.
JoB
Except that we know that “Ixion” primarily is the name of the *company* operating there, *as well as elsewhere* (since there’s no indication that Calcine’s workplace is still within *this* system), so I try *not* to use it for the system as well. 😉
https://jayrockin.tumblr.com/post/754667784412200960/reader-questions-from-chapter-1-of-runaway-to-the
(To add insult to injury:
https://en.wikipedia.org/wiki/28978_Ixion
)
… wait, do you mean “names for the *system*” as *opposed* to “names for its *sun*”? Interesting concept, AFAICT one that RL humanity has *never* used yet …
Jay Eaton
This may shock you but one word can colloquially be used to refer to multiple things
JoB
@Jay I’m a mathematician, I’m not supposed to *join* my fellow humans in their well-known pursuit of The All-Meaning Grunt. 😉