isaackuo

isaackuo, 1 day ago

So, LH2 tank engineering is not trivial. If you want it to launch from Earth, then you have to confront icing and insulation. For various reasons, this works best with a single layer of structural tank, with insulation foam applied outside that and optional paint outside that.

But this becomes a problem if you have dreams of using these big LH2 tanks for a space habitat. Bits of foam breaking off becomes space debris - a hazard in LEO.

1/2 #PostcardsFromCutty

isaackuo, 1 day ago

Thus, Essex was not allowed to operate in LEO, severely limiting its ability to bring in revenue. Besides, its avionics and various systems degraded and became obsolete, so Essex was scrapped.

Cutty's ship would be built around its LH2 tank, repurposed into a crew compartment. Spraying the outside with large cellulose bubbles both solved the problem of space debris and provided Whipple shield-like impact protection.

2/2 #PostcardsFromCutty

isaackuo, 1 day ago

@steinarb @nyrath

There's not much in common between this new concept and Daedalus. For one thing, it uses fission rather than fusion.

And the basic idea is wild ... take a gun-type fission bomb and make it so that the cylinder portion is reusable while the bullet portion gets super duper hot.

I'm no nuclear physicist, so I don't even know if that can even plausibly work.

isaackuo, 3 days ago

@Hcobb @nyrath

The ideal size is not seven. Blakes 7 just couldn't ever get the hang of giving all the characters something to do.

isaackuo, 4 days ago

@nyrath

Page 7 "optional boom" ... Captain Ivanova does not approve.

isaackuo, 5 days ago

@lorenschmidt

Hmm ... the roads seem to strongly tend to be aligned with 45 degree diagonals. I feel like roads that are more orthogonal feel more "traditional".

(See, for example, Phantasie.)

isaackuo, 6 days ago

@masukomi

I think it's really just habit, established by D&D. I mean ... D&D was ridiculously popular and it established all sorts of conventions.

Furthermore, D&D inspired a ton of CRPGs and RPG-like games (such as roguelikes). In those games, there wasn't really a capability to replicate the role playing aspects of D&D, but it was straightforward to replicate the numerical mechanics, such as leveling up.

A lot of people were introduced to RPGs via these games first, rather than tabletop.

isaackuo, 8 days ago

@nyrath

I kinda like the idea of taking inspiration from wooden ship days. Back then, it might not be so much a matter of different purpose built logistics ships, but rather a ship's purpose could evolve with age, as it gets worn out.

https://en.wikipedia.org/wiki/Hulk_(ship_type)#Hulks_used_for_storage#Hulks_used_for_storage)

isaackuo, 9 days ago

@cstross

What you're suggesting pretty much can't be done, in terms of orbital mechanics. In order to achieve global coverage from LEO satellites, they need to be in a bunch of different orbital planes.

(And also, in LEO it takes a lot of fuel to do orbital plane changes.)

So that means it's impossible for a Starship upper stage to pick up more than a few of them for return.

It makes more fiscal sense to just let them burn up in the atmosphere and let others pay the externalities.

isaackuo, 9 days ago

@cstross

The ion thrusters on Starlink satellites definitely have better performance than typical satellite thrusters, but even so ... it takes a lot of delta-v to do plane changes in LEO.

It could take much less delta-v to move up to a graveyard orbit (where atmospheric drag is negligible).

isaackuo, 9 days ago

@cstross

They're not going to be in one graveyard orbit, but a whole bunch of different ones.

And if they're in graveyard orbits, why not just leave them there?

isaackuo, 9 days ago

@cstross

Your ethernet cables don't go obsolete in 5 years, though.

But maybe I'm misunderstanding. I thought the idea was that the Starlink satellites would need to be replaced after 10 years (or 5 years maybe) due to obsolescence. In other words, it's not about keeping them in use, just deciding what to do with them at EOL.

Is that right?

isaackuo, 9 days ago

@cstross

Okay, thanks for the explanation.

There has been, for some time, attempts at coming up with schemes to refuel satellites. So far, this hasn't led to anything successful; the orbital mechanics of the situation is pretty daunting.

But for a Starlink specific solution, it could make sense to design supply modules that a Starlink satellite rendezvous with to get more propellant and/or a new payload comms package.

No need to return stuff to Earth, just receiving supplies/upgrades.

1/2

isaackuo, 10 days ago

@maxthyme @nyrath

Worth noting that this was done in space, at zero gee rather than low gee. Skylab had a circular track made of small cabinets.

https://www.youtube.com/watch?v=qiMq-fdRhLo

isaackuo, 9 days ago

@KarlSchroeder @nyrath

Martian gravity is .38g, whereas lunar gravity is .17g. So, the floor angle to simulate 1g would be 22 degrees rather than 10 degrees.

So basically, it would work about the same as on the Moon, just with about twice the floor angle (not all that much different in the big scheme of things).

isaackuo, 14 days ago

@tkinias

I can't say I'm optimistic that it would have led to any sort of fusion power, but it could have encouraged more people to go into physics knowing there was a well funded jobs program for it.

Also, it's possible we might have a spinoff technology to show for it all.

For example, the VASIMR thruster that has been going nowhere for two decades was a spinoff from MCF research.

Maybe we could also have a Z-pinch spinoff thruster and a pulsed laser thruster going nowhere for decades.

isaackuo, 14 days ago

@tkinias

I think that fusion research physicists actually have a pretty realistic idea of what the money would likely result in, but they know this won't get them the funding.

So, if this money isn't wasted of fusion research, I expect it would be wasted on some other field which is 2nd best at making duplicitous promises. Maybe solar freakin roadways.

The challenge is to figure out how to design and maintain a system that can disincentivize the B.S.

isaackuo, 15 days ago

@Aaron_DeVries @nyrath

There are also weird possibilities related to neutrinos, dark matter, and/or dark energy.

isaackuo, 16 days ago

@Hcobb

Another approach was used in Legend of the Galactic Heroes - remove all resources from the frontier worlds, so the liberators have nothing to liberate (other than hungry locals).

This strategy would have been political disaster for the Democratic side, but for the Imperials the locals simply had no realistic choice but to comply.

1/2

@eldadoinquieto @nyrath @peterdrake

isaackuo, 16 days ago

@Hcobb

If transport costs make it impractical to hoover all the resources from frontier worlds, an alternative is to torch the resources rather than let them be plundered.

The resources are stored with "self destruct" flame throwing and/or flooding systems. So, the raiders can't steal the resources.

Of course, if you compensate the victims when the burn system is activated, this sets up perverse incentives to game the system ...

2/2

@eldadoinquieto @nyrath @peterdrake

isaackuo, 15 days ago

@Robert_Brandt

The bribe has to be significantly cheaper, because it funds the continued operations of the space horde - making it easier for them to do it again, and also incentivizing them to do so.

In contrast, military action depletes resources from the space horde and incentivizes them to do something else or go elsewhere.

Of course, it's also possible to use a bribe to buy some time, to build up a more credible deterrent. It's not a binary.

@Hcobb @eldadoinquieto @nyrath @peterdrake

isaackuo, 15 days ago

@Robert_Brandt

A non-military deterrent might be possible. I mentioned the idea of threatening to burn stored resources rather than allow them to be plundered.

Various difficulties like getting local buy-in to the strategy are left as an exercise for the players.

@Hcobb @eldadoinquieto @nyrath @peterdrake

isaackuo, 15 days ago

@Hcobb

This is why you use remote detonated mini squash head warheads.

First you shoot the squishy sticky squash heads at the target. Then you designate one to detonate (it has flashing LED to indicate it's the one primed to detonate).

Then you remote command it to go boom, mitigating collateral damage.

@eldadoinquieto @Robert_Brandt @nyrath @peterdrake

isaackuo, 15 days ago

@nyrath

In the meantime Matt Murdoch is running around lasing everyone and everything everywhere like a madman, maniacally laughing.

@Robert_Brandt @Hcobb @eldadoinquieto @peterdrake