You'll Want Us High and Clear - General

November 2024

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Dean <dsdy120@gmail.com> on 2018-10-16 21:54:43 wrote:

How does this setup even work under thrust? Do the cryocel tethers rotate at an obtuse angle with respect to the main tether?

Robert Houghton <sudragon2k3@gmail.com> on 2018-10-17 03:07:55 wrote:

I’m thinking, that at cruising thrust, the spinhub would have to be turning at a decent rate to avoid the cryocels and their tethers from tangling. Torque would be …interesting.

I’m also trying to imagine this thing turning end for end to decelerate. How long does it take to reel in the cryocells?

AMS <adshea@gmail.com> on 2018-10-17 07:16:24 wrote:

Wouldn’t turn end over end. The drives vector as needed and you’d want the hull ahead of the cargo at all times to avoid debris strikes on the explody stuff.

Dean <dsdy120@gmail.com> on 2018-10-17 19:55:58 wrote:

Seeing as this is a tractor system, with the hull pulling on the spinhub via a long tether, leaving it ahead of the spinhub during deceleration would be disastrous. The cryocel tethers probably have to retract, and the entire thing flips end over end on the main tether, before the cryocel tethers extend again.

Alistair Young <athanasius.skytower@arkane-systems.net> on 2018-10-18 04:02:58 wrote:

No need to go end over end. The spinhub’s basically a spinning ring mounted to a fixed ring; a soft touch on the controls, and you can switch from core-for’ard accel to core-aft decel by threading the needle. Much simpler.

Dean <dsdy120@gmail.com> on 2018-10-19 06:58:34 wrote:

Threading the needle… must be the most fun they have on long trips!

AMS <adshea@gmail.com> on 2019-02-12 13:55:36 wrote:

If you’re moving the hull fore and aft, what are you using to shield the cryocells from MMOD (or MMSD as the case may be)?

Alistair Young <us@arkane-systems.net> on 2019-02-12 14:33:18 wrote:

The cryocels, in this case, are their own little subhulls with the usual Whipple shields, kinetic barriers, and pd grid.

Alistair Young <athanasius.skytower@arkane-systems.net> on 2018-10-18 03:59:02 wrote:

Yep. Pay out more or less tether as required to maintain proper separation.

Scott <scott.kenny@gmail.com> on 2018-10-17 22:16:58 wrote:

Y’all are all forgetting the vector-control system, which effectively leaves the entire ship behaving as if it’s coasting in emgee while under thrust.

R.C. <richardjacole84@hotmail.com> on 2018-10-18 03:33:47 wrote:

I’m pretty sure that using vector control for inertial dampening requires gravity rotors, and therefore can’t be applied to an entire ship, as the rotors have to be attached to something that won’t be within the field they generate.

Scott <scott.kenny@gmail.com> on 2018-10-18 20:26:42 wrote:

I’ll defer to Alistair, but based on other descriptions you don’t need grav rotors for inertial damping. At least his designs don’t push obscene gees that would reduce the crew to a smear on the aft bulkhead if the inertial compensators failed under thrust.

R.C. <richardjacole84@hotmail.com> on 2018-10-19 05:22:53 wrote:

From Handwavium: Inertial Dampers :

"All inertial damping actually is is… artificial gravity.

This brings with it all the associated limitations. For example: you can only create the a-grav field between matching and opposed sets of gravity rotors. (Well, that’s not technically true – but not having the second one there means you’re trying to attract about half the universe with your a-grav field, energy requirements head asymptotically for infinity, fuses blow, and you’re done here.) It’s basically an internal closed field, with very little spillover at the fringes. Forget a-graving anything in open space or cheating your way to a reactionless drive with them; you need something to mount the rotors on, and that thing is not going to be within the field of effect."

Dean <dsdy120@gmail.com> on 2018-10-19 07:14:57 wrote:

But you can use vector-control grabbers of the type they use to swat incoming weapons fire or use in gravy weapons to the same effect, no?

Robert Houghton <sudragon2k3@gmail.com> on 2018-10-19 10:21:28 wrote:

mmmmm…gravy

Ru <shearwater+eldraeverse@gmail.com> on 2018-10-21 11:24:22 wrote:

Vector control is used for all sorts of inertia and momentum trickery; inertial dampening is apparently only one aspect of it, which implies that the other aspects do not work in quite the same way. Note that the article you quoted says that reactionless drives using artificial gravity don’t exist, but “reactionless” drives using other vector control techniques do.

IIRC, there has been some talk in posts passim about using vector control to do stuff like make your poorly-loaded-and-balanced freighter still travel in a straight line under thrust and spin around nicely without bits whipping around or snapping off. This implies that, to a certain extent, you might be able to operate a payload-onna-string ship as if the connecting cable were rigid.

Alistair Young <us@arkane-systems.net> on 2018-10-21 16:08:28 wrote:

Okay, here’s the thing:

“Vector control” is the name for a whole family of related ontotechnologies. For most purposes, there are three primary kinds to be concerned about:

The one that jiggers about with the coupling constant between true mass (i.e. energy-equivalence) and inertial mass. And which, most importantly, can do this across a field boundary rather than directly, which is why it doesn't make matter fail in a variety of interesting and potentially explosive ways. Has many applications, for which consult Mass Effect.

The one that creates paragravity between two opposed poles. Also used for inertial damping, because as long as the frame of the starship is strong enough to cope with the real thrust and the poles are bolted to it well enough to stand the reaction to the action, internal opposed paragravity works just fine for that.

The one that allows non-local momentum transfer. Could be used to build a reactionless drive that isn't really a reactionless drive; it's just that you don't need to be next to whatever is receiving the equal and opposite reaction. Hope it doesn't mind being leaned on by a starship. Comically inefficient, and a pain in the ass to use for anything except classroom demonstrations.

Could, and occasionally is, used to build overly fancy and impractical starships made of multiple disconnected pieces that "magically" all move together - mostly by people who really want to show off and aren't worried about having to somehow fetch the missing bits if the machinery glitches out.
Is mostly of use for momentum-conserving tractor-pressor effects.

Alistair Young <us@arkane-systems.net> on 2018-10-21 16:19:06 wrote:

Now, trying to do that “make your poorly-loaded-and-balanced freighter still travel in a straight line under thrust and spin around nicely without bits whipping around or snapping off”, however - that isn’t going to work.

You’ll notice all the examples I give of non-local momentum transfer are between two disconnected objects. That’s because bad things happen when half a physical object suddenly finds itself with a radically different momentum than the other half; which is to say, if you were to try to use it to balance out the thrust on your poorly loaded freighter, you’re either going to crumple your thrust frame up on one side, snap it in half on the other, or probably both.

(There are almost certainly ways to kluge around this limitation with sufficient bastardgineering, but since all of those amount to expensive ways to quarter-ass your way around the problem of hiring a cargomaster who isn’t an idiot, they’re not exactly a major subject of research. )

Ru <shearwater+eldraeverse@gmail.com> on 2018-10-22 03:02:59 wrote:

Now, trying to do that “make your poorly-loaded-and-balanced freighter still travel in a straight line under thrust and spin around nicely without bits whipping around or snapping off”, however – that isn’t going to work.

So, I was fairly certain that I wasn’t making this up, so I’ve done a bit of an archive crawl.

We have this: <a href=The Sapphire Coloratura: Revealed!">The Sapphire Coloratura: Revealed! with the relevant quote

First, its radiators, which cloak the center of the mechanical section with a divided cylinder of gridwork, individual carbon-foam emitting elements held together and in place away from the hull by vector-magnetic couples, linked back to the ship itself only by the ribbons of thermal superconductor transmitting waste heat to them;

And also this: Next Question Batch which says

Of course, if you have a vector-control core to evenly spread change in momentum out across your entire starship, the containers don’t feel relative acceleration and you can stack them as “high” as you want, so long as the mass will hold together under non-thrust stresses and you don’t mass-out or bulk-out the ship in the process.)

The latter being the moost obviously relevant one. In both cases, vector control is apparently being used to spread angular momentum out across a structure.

you’re either going to crumple your thrust frame up on one side, snap it in half on the other, or probably both.

So long as you don’t exceed the physical limits of your structure (and on spacecraft running trajectories that don’t require massive accelerations and sudden manoevering, which will be the vast majority of them, you’d be hard pressed to do this) you’ll be fine, right?

Alistair Young <us@arkane-systems.net> on 2018-10-23 02:51:02 wrote:

The former is an example of (C); it’s just using tractor-pressor-torquor functionality to make the radiators (and the subhulls) hold position; nothing fancy going on there that you couldn’t replace with physical material if you were so inclined.

The latter is me screwing up and misspeaking; it’s the the paragravity mode of vector control used for inertial damping that sustains microgravity and lets you stack the cargo containers high, not the VC core. My bad.

So long as you don’t exceed the physical limits of your structure (and on spacecraft running trajectories that don’t require massive accelerations and sudden manoevering, which will be the vast majority of them, you’d be hard pressed to do this) you’ll be fine, right?

I would not expect so. Transferring momentum (and therefore velocity along with it, since mass is constant) out of part of a (mostly-rigid) structure with vector control is basically like dropping the velocity of half a car and leaving the other half alone.

With results fairly similar to a drive directly into a bridge support. Even at low speed, it ain’t pretty. And in this scenario, it’s going to be prolonged until either the VC equipment or drive fails or is shut down.

crumple

September 2025

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It was mentioned once that the command base of the Republic Home Fleet had an incident with its antimatter containment bay.