Toughsf

The best arguments I saw were here: https://toughsf.blogspot.com/2025/05/the-laser-revolution-part-i-megaw… https://toughsf.blogspot.com/2025/05/the-laser-revolution-part-ii-grou…

Ah, lovely to see Murderbot mentioned, I've just been re-reading it. I think it's fine to take scifi tech with a grain of salt; most authors skip the absolute technical details so we just have to assume that things work in some way we don't currently understand. Someone did the calculation for the Epstein and it doesn't look great: http://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html but only based on the vague technical details provided in the books. The Jean Le Flambeur trilogy is one of my favourites, it does a LOT of quantum hand-waving but the price is worth it for all of the amazing things in that universe. "This sounds so fucking cool" > "That wouldn't work irl" for good sci-fi imo. As long as they don't mess with thoroughly understood concepts and rely on "things we don't know yet".

Lasers. No really, near-future laser systems with adaptive optics and good spotting - for example distributed SAR satellites - dramatically shift that balance [0]. [0] https://toughsf.blogspot.com/2025/05/the-laser-revolution-part-i-megaw…

Regarding reproduction, I'm willing to write that off to advanced medical technology doing DNA repair. Most of the plot wouldn't be that different with slower space drives, so I wasn't too bothered by that either. But fwiw, it turns out it is possible to get that level of rocket performance, if ToughSF got their numbers right: https://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html It wouldn't look the same and the power level would be higher than what all of civilization uses today, but the amount of fusion fuel isn't all that remarkable. The design uses helium-3, which could be collected in large quantity from Uranus and Neptune.

Perhaps for casual readers. But say you write a pop culture hit, people start looking deeper, and the gaps become glaring. Like the fusion drives in the expanse, it's hand waved on the first read through, but on the second I found that someone had calculated it online (like this https://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html?m… and now it kinda ruins the vibe, the author should have chosen something outside of current science (basically magic) or used a technology that's feasible. Also, the ships fucking explode when they lose magnetic fusion containment...whereas in reality it would just dissipate...

You can radiate it away, but it would be really hard compared to just dumping it to atmosphere / water bodies. Especially as computers need quite low temperatures. Here is some more analysis on the problem of radiating heat away in space: https://toughsf.blogspot.com/2017/07/all-radiators.html

that’s some tough SF…http://toughsf.blogspot.com/2020/07/tethers-all-way.html

I'd like to share an interesting read about the prospect of a nuclear-powered Starship. (http://toughsf.blogspot.com/2021/10/nuclear-conversion-for-starship.ht… Basically, it's not much about safety, it's also that the benefits of nuclear are marginal compared to what the Starship is already capable of, and in many mission configurations, it's actually worse.

Here is an article on this topic that goes heavily in depth on the topic: http://toughsf.blogspot.com/2018/04/permanent-and-perfect-stealth-in-s… Note that this is for strategic level stealth, which is to say your enemy doesn't even know you're in system. Tactical level stealth is vastly easier, and can be as simple as launching several hundred thousand heated decoys into system before entering yourself - one of these is the attacker, can you find which? This last strategy is actually what we'd implement if ever anyone tried to seriously develop anti-ICBM technology.

There's a writeup here that you may be interested in, if you haven't seen it already: https://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html The author suggests creating a fusion reaction well behind the ship, but channeling the useful parts of it in an electromagnetic field tunnel to create thrust while dissipating the heat more effectively. Vaguely like Project Orion, but with a more-or-less continuous external fusion reaction instead of a series of nuclear explosions. I am not a physicist, but they seem to have done their homework.

Sounds like the Epstein Drive, perhaps version 0.1: https://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html

If we're talking of this kind of efforts, why not to discuss this - https://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html . Seems in the realm of physics, with some more impressing results...

Okay, so it's a stealth ship: http://toughsf.blogspot.com/2016/10/the-hydrogen-steamer-stealth-space…

Rather the opposite isn’t it? What you’re saying is ‘regardless of relative benefit or cost, humanity would make the decision to do interstellar travel - because reasons’. I’m pointing out that relative benefit and cost matter and tend to drive decisions - and that the massive cost with (currently) no plausible benefit which could outweigh it, makes it unlikely we would end up taking that course. Unless we discover new physics, or new ‘value’ somewhere which would justify it.* Energetically, for instance, even if we found a planet of pure most expensive thing we can think of (except perhaps for antimatter, though that is a more complicated discussion) just a few light years away, it would never be economic to go get it based on our current understanding of physics. Even sending a physical probe would be of dubious value, especially considering everyone who would be alive or benefit from anything it could ever provide (including information) would be long dead before we could even find out if it could talk to us over those distances or had arrived. This is so obvious, btw, that sci-fi writers always have to come up with new physics (or outlandish extrapolations of current thoughts on potential physics - see the Expanse’s Epstein drive, or Star Trek warp tech and subspace communications) for the story to be even a little plausible or interesting. [http://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html?m=… And it always has to be a mcguffin, because…

> The idea that a magical new engine would suddenly appear that made many of the things in the tv series possible. Assuming you're talking about the Epstein Drive and not the protomolecule... it didn't suddenly appear, it was invented. And, surprisingly enough, it's way closer to realistic than most scifi. http://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html?m=… > The idea that there would be a complete backtrack in labor rights and labor safety (the ice asteroid mining scene). What labor laws cover the asteroid belt today? Or, closer to home, the moon? If an earthly nation claims some territory out there its own and seeks to enforce the law, that's one thing. But what if a private company sends workers out there in unclaimed space? Humanity hasn't had access to such a lawless frontier in centuries, but we've got a lot of ugly history to look back on. Civil rights are not won by optimists, they're won through bloody and protracted fights. Look no further than Apple to see that companies in today's economy are still fully on board with slavery and sweatshops, and Apple is one of the "good guys" known for holding vendors' feet to the fire over human rights abuses.

The reason I'm personally most excited is interplanetary or even (generation ship) interstellar travel. Fusion fuel is the only practical fuel we know of with enough energy density to provide enough "umph" for long-distance trajectories to be traveled along, at speeds faster than what the Voyager probes had to achieve using multi-year planetary slingshot trajectories. Fusion rocket information: https://en.wikipedia.org/wiki/Fusion_rocket https://www.iter.org/newsline/-/3303 http://www.projectrho.com/public_html/rocket/realdesignsfusion.php A supplement to a fusion power plant: https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_… http://toughsf.blogspot.com/2019/10/the-expanses-epstein-drive.html The only fuels that could achieve better energy density than fusion fuel would be antimatter, or maybe some fanciful sci-fi thing we may discover down the line, such as quark fusion ( https://www.sciencealert.com/new-quark-fusion-releases-significant-ene… ) or subatomic compression ( a concept from fiction that involves packing an immense amount of solid electrons together so tightly that the electrostatic repulsion functions as a compressed spring (perhaps using mutual gravitation almost but not quite strong enough to be a black hole as a way of preventing disastrous spontaneous decompression) ).