KSK

I suppose it’s not really the kind of thing you think about, unless you’re actually working in the industry or until something appears to go demonstrably wrong with the system. Same with most industry sectors really. Anyhow, thanks for the informed view and I’ll give that article a read.

Agreed but I was giving them the benefit of the doubt on that one. It's also tempting to draw a parallel between their preference for self-certification (737) and their preference for extensive simulation rather than flight testing (Starliner) but a) I don't know nearly enough about this to tell whether that's a fair parallel and b) it seems a bit tasteless to drag the 737 tragedies into this.

I'm not much good for checking wargaming rules I'm afraid. I haven't ever played KSP as a space war game (modded or stock) so I don't really have any idea of what's balanced and what isn't. I've had a look at the thread but can't find a great deal of story to comment on either. The quote on the first post is a bit odd though: "Fuel shortage, Cold war, Privatization, and the Abundance of resources in the Kerbal system has lead to The Great Kerbal War. Which ravaged the Kerbal system for 4 years..." Without more material to work on, it's not immediately obvious to me why any of those factors would lead to war: If Earth history is anything to go by, a Cold war is what you get when the protagonists are too well armed to engage in an actual shooting war without destroying themselves. Privatisation (of what?) doesn't seem like a reason in itself for war. A lack of resources seems like a more plausible reason for war than an abundance of them. How did the Great Kerbal War last for 4 years (or even get started) with a fuel shortage in progress? Fair warning - I'm kind of biased against space war in general so you may want to get somebody else to critique this. I'd try not to be critical for the sake of being critical but you can probably expect quite a few questions like the ones above.

Pretty much - and if I remember rightly (it's been a few years so I may not be), NASA agreed to change SpaceX's commercial cargo contract such that they were only obliged to do two COTS Demo flights rather than three. A couple of caveats before I carry on with this post: I'm a SpaceX fan. I make no secret of that and I think my posting record on SpaceX related topics speaks for itself. With that said I do try to be a fan and not a fanboi (with all the negative connotations that usually go along with that word.) If Boeing were able to complete all the required tests apart from the actual docking on their test flight, I think that NASA could reasonably argue that that is good enough. Hopefully, by now we can be reasonably confident that the actual docking adaptor will work as advertised, so provided that Boeing have shown that Starliner can safely carry out the maneuvers necessary to rendezvous with ISS and approach it at a suitable relative velocity for docking, then yeah - good enough. Beyond the blindingly obvious (test thrusters to demonstrate that Starliner shouldn't accidentally ram ISS), I don't really have much of an idea what's involved with 2. If SpaceX were in the same situation as Boeing are currently in, I would expect them to be arguing just as hard that another test flight wasn't required. With all of that said, I don't think it's terribly difficult to see why there's been an online backlash against Boeing, at least in some circles. There is a need to get Commercial Crew flying. However, that's been the case for the last couple of years. Waiving a contract requirement now in the name of 'getting this done' rings a trifle hollow. NASA have shown themselves to be perfectly willing to lean on the contract for SpaceX. (Propulsive landing you say? Nope no extra money for that. You'll be validating that on your nickel. COPV - yeah we don't really trust that, go design us another pressure vessel). Being even-handed and presuming they've been similarly rigorous with Boeing (I'll freely admit that I haven't been following Starliner the way I've been following Dragon 2) - why does Boeing get out of it's contractual obligations now? It's really not hard to see this as a play by Boeing to avoid absorbing the costs of another test flight. Sucks to be them - perhaps they should have had their lawyers read up on these new-fangled 'fixed price contracts', before signing up to one. Boeing, after all, are about the biggest of big boys. Finally, all the above might have garnered more sympathy, or at least a fairer trial in the Court of Internet Opinion, if Boeing weren't dragging around a history of being overpaid for underdelivering on SLS.

Gods but I loathed that stupid slogan. It killed any sort of nuanced debate about many topics, in that anything that a given person disapproved of on the internet immediately got described as 'evil'. Not to mention that half the time, if Company X did something it was fine, but if Company Y (who typically operated counter to whatever groupthink was prevalent on a given forum) did that same thing, they were 'evil'.

They seem to be making a decent fist of the first three and they'd better git gud at the fourth if they want to fund their Mars ambitions. After that - agreed.

Well you still need to travel from your slingshot to your destination which will take some time but yes - good point. Was forgetting about the teleport-and-repeat trick.

Not a clue (although this page might help if you want to crunch the numbers yourself) but I can think of a couple of comparisons. The Apollo spacecraft were travelling at approximately 1km/s as they entered the Moon's sphere of influence. Therefore looping around the Moon on a free return trajectory would be a rather extreme slingshot maneuver, adding at least 1km/s of delta V (to get the spacecraft turned around) and in practice quite a bit more (to get the spacecraft heading back towards Earth). Unsure of the exact numbers. Time from sphere of influence entry to lunar orbit insertion (LOI) burn was about 12 hours. So the Moon's gravitational field is enough for low single-digit km/s delta-V changes over a day. More impressively, Voyager II picked up around 18km/s from its Jupiter flyby. No idea about times. But yes, relying on slingshots alone would probably take quite a bit of time. Using slingshots and engines would take rather less of course (remember that 0.07g drive taking 10 days to travel 1 AU? That's spending half the journey braking. Accelerating at 0.07g for 5 days gets you about 300 km/s delta-V (assuming my maths is right. It's getting late here so it may not be ) and travelling at 300km/s would get you from Earth to Jupiter in a month. Assuming you didn't plan on stopping at Jupiter. So, very roughly speaking, you're looking at weeks to months of travel time to get around a star system. Using your jump drive, you could scout out the Alpha Centauri system and get back to Earth, in a handful of months. That's not Star Trek journey times by any means but it's still pretty impressive and can be done in a much harder sci-fi setting than Star Trek (admittedly, not a high bar to clear.) What's the big hurry anyway? Here we're talking about interstellar journeys in a very small fraction of a human lifetime. More to the point for a sci-fi setting, you could have 'interstellar mail ships' delivering communications between planets in a reasonable timeframe for those planets to interact with each other in a meaningful manner. You could have an interstellar civilization held together by the interstellar equivalent of the old Pony Express! Loads of story telling potential there. To my mind it would also strike an interesting balance between 'space is routine' and 'space is hard' which seems to be something you've been looking for?

Or go with @Terwin's slingshot ideas. Alternatively you could have a ship with a separate lander (high thrust antimatter engines, gets your crew to the surface and back) and mothership (high ISP antimatter engines, gets the crew everywhere else). It may also be worth noting that 1g constant acceleration is really quite overpowered. Lifted directly from the Project Rho site: "Consider a 1,000 ton spacecraft with a 10,000 km/s exhaust velocity and an acceleration of 0.722 m/s/s. For a 1 AU trip at constant acceleration, flipping at the midpoint, it will take 10.5 days and consume 66 tons of propellant/fuel." It's stating the obvious but 0.7ms-2 is only 0.07g (roughly) and still gives you a fairly impressive journey time for quite a reasonable quantity of propellant. 1g is nice for providing artificial gravity en-route but it's not required for decent journey times. I haven't looked it up but I suspect that a 0.07g acceleration and 10,000 km/s exhaust velocity is feasible with quite a few of the engines listed on Project Rho. As for a lander - my apologies for sounding like a busted record - but here's another Project Rho snippet that might be of interest: "The low mass ratio of antimatter rockets enables missions which are impossible using any other propulsion technique. For example, a reusable antimatter-powered vehicle using a single-stage-to-orbit has been designed [Pecchioli, 1988] with a dry mass of 11.3 tons, payload of 2.2 tons, and 22.5 tons of propellant, for a lift-off mass of 36 tons (mass ratio 2.7:1). This vehicle can put 2.2 tons of payload into GEO and bring back a similar 2.2 tons while using 10 milligrams of antimatter. Moving 5 tons of payload from low-Earth orbit to low Martian orbit with an 18-ton vehicle (mass ratio 3.6:1) requires only 4 milligrams of antimatter." 2.2 tons of payload is a bit puny for a standalone SSTO (although you can't complain about a 36 tons wet mass!) but it should be plenty for getting a few crew down to the surface and back from an orbiting mothership. The propellant is unspecified but water should be fine (I say this because several of the thermal-antimatter rockets described on the site use water) and is likely to be widely available and more convenient to obtain and store than hydrogen. TL:DR - yes I think your VentureStar based single-stage-to-anywhere idea will require cheating. However, you could probably devise a fairly hard sci-fi alternative, where the only 'cheating' is your original jumpdrive concept without built-in velocity matching. Personal opinion - if you must arrive, then arriving by jumping into the system, performing a daring slingshot maneuver to match velocity with your target planet and then using your awesome antimatter engines for final approach and orbit insertion is both pretty damn cool and lets you, the writer, get a bit of actual astrogation into your spaceflight story. Which is always nice to give it that hard sci-fi feel Plus it allows time for some other bits of storytelling, for example: The crew are scanning their destination as they approach (maybe firing off a couple of probes in the process). Everything looks fine - until they light the engines for final approach just as one probe mysteriously vanishes... The crew need to pull off a daring escape. They can do it - but only by using a recklessly brave slingshot maneuver which takes them dangerously close to [your celestial body of choice] to get every last m/s of delta-V from the Oberth effect...

A couple of comments. The jump-drive figures are inconsistent. If it requires 1 hour to spool up and can jump 7 light years a go, then surely it only takes 10 jumps to traverse 65 light years? In which case you'd be spending 10 hours spooling up rather than 65? Unless you meant 1 hour per light year spool time. It would help to post some useful figures on VentureStar - the ones posted don't let you calculate much of anything, particularly since those linear aerospikes and H2/LOX are presumably being replaced by your antimatter engine and some propellant? More generally, I had a quick look on the Project Rho site and couldn't really find a suitable 'off-the-shelf' antimatter engine for this scenario. If you want a decent thrust-to-weight ratio - required for that 1g acceleration - then you're looking at some form of anti-matter-thermal rocket, with ISPs in the 1-2K range. That doesn't really seem to be enough here. A 2000s specific impulse certainly isn't anything to sneeze at but for a 100km/s delta-V change, you're looking at a mass fraction of about 0.0016. In other words, for a 100 ton spacecraft, all but 0.5 tons is propellant. That's very rough and ready but it gets the point across I think. On the other end of the scale, there's the utterly insane Beam Core engine with a thrust to weight ratio of 102 and an ISP of over 10 million (not a typo). Which sounds like the kind of go-anywhere-do-anything engine that would laugh at a mere 100km/s delta-V change. Unfortunately, it has the slight (but awesome) disadvantage of annihilating about 50g/s of antimatter. I imagine that the mass of shielding and cooling systems needed to deal with that kind of energy output will laugh just as hard at that puny 102 thrust-to-weight ratio and I'm pretty sure the resulting spacecraft won't be pulling 1g. Unfortunately that seems to be the general pattern for pure antimatter rockets. Awesome ISP or decent acceleration but not both.

The Apollo 13 soundtrack works for me. Or at least this part of it does:

I have no real insight on this but I would have thought that they'll want to make it as easy as possible for customers to switch to Starlink. On that basis, I'm guessing the former, rather than anything super proprietary.

Better hope the administrator is loyal as well as capable then, otherwise you have 25 years for them to organise a capable defense to greet the overlord's fleet. You could create a mighty big debris field along an approach vector in 25 years or put a lot of nuclear missiles in orbit , both of which are going to be bad news for the approaching fleet. Unambitious would help too, to prevent that capable administrator deciding that they can rule the place better than their supposed liege. Besides, if I was a capable administrator plotting rebellion, I wouldn't hoist a metaphorical middle digit at my liege lord and dare him to send his fleet over. I would have prepared this well in advance - which shouldn't be too hard to hide when any round trip communications between myself and my lord take the best part of a decade or more. Besides - what is that fleet going to do if and when it arrives? I suppose it could nuke the rebellion from orbit, which is fairly counterproductive. One less functioning planet in the Empire and a big warning sign to any other would-be rebels to get their defenses well organised before declaring independence. Or perhaps it could send in the drop droops for a happy fun guerilla campaign on the ground, against a prepared opposition. Conceded. However, my original post made no actual mention of government: "For clarity, I’m defining an interstellar civilisation as one where interactions between star systems are easy enough that the inhabitants of one star system can participate in the affairs of another system if they choose to, either in person or less directly, for example by purchasing goods sourced from another system. Without that participation, I would argue that you don’t have a civilisation." 'Participate' doesn't have to be limited to governing participation. It could be cultural participation or, as I tried to suggest, economic participation. Without regular interactions between star systems, there will be no common culture or language or religion that one could define a civilisation by. Assuming that your 25 year journey time is a reasonable one, by the time a visitor from System A gets to System B and back, System A's local culture has moved on by 50 years and, more importantly, what they're bringing back from System B is culturally, 25 years out of date. I suppose Systems A and B could interact by radio (or comms laser or whatever), in which case Systems A and B will only be about a decade out of synch. And in any case, there's a limit to what can be shared in such a way. Sending a picture of one's planet doesn't really convey what its like to live on that planet, to deal with the local peculiarities of geography, climate or flora and fauna. There's very little actual shared experience to build a shared culture on. And all this is assuming that the cultural exchanges are generally positive and, for example, that the latest theological speculations at System B aren't decried as heresy by the inhabitants of System A. To summarise, without some form of faster-than-light travel, I believe the idea of an 'interstellar civilisation' is an impractical nonsense. At best one would have a collection of autonomous star systems that may or may not choose, or be able, to undertake limited interactions with each other. An interstellar government of any form, limited to lightspeed communications and sub-light journeys between the stars is not possible (and I reiterate that there seems to be no obvious practical function for such an overarching government anyway). And similarly, lightspeed communications and sub-light travel will not allow sufficient interactions between star systems to create a shared language, cultural identity or anything else that could be called an interstellar civilisation. Going back to @Scotius's comment, I believe that once the technological capacity for an interstellar civilisation exists, that same technological capacity will either negate the reason for conflict or render them moot.

@Dragon01 You’re conflating ‘repressed’ with ‘poor’. That isn’t necessarily the case and I’m sure you can think of the obvious example from WW2 without me straying into forum unsafe topics. I disagree that civilisation =/= government. A civilization implies an organised society. Organisation beyond a fairly basic level requires an organising structure or body. Which is a government by any other name. Your feudalism example is still a government. But in any case, once your communication times and travel times between nodes of your civilization get large enough then you have a civilization in name only. How long is your planetary governor going to stay loyal to their feudal overlord when that overlord is several tens of light years away and functionally incapable of enforcing their orders? Even if the governor remains loyal, how long will the population at large remain loyal to that far-distant figurehead? As for a Colonial Empire, please tell me you’re not serious. That hasn’t even proved to be workable on a planetary scale (see: the history of the United States) where distances and communication times made it possible, at least in principle. Over interstellar distances where lightspeed is a limiting factor, the concept is dead on arrival.

@Dragon01 All that may or may not be true but what you’re describing is hardly an interstellar civilisation in any meaningful sense. For clarity, I’m defining an interstellar civilisation as one where interactions between star systems are easy enough that the inhabitants of one star system can participate in the affairs of another system if they choose to, either in person or less directly, for example by purchasing goods sourced from another system. Without that participation, I would argue that you don’t have a civilisation. If communications are limited by lightspeed then the ability of a government to impose its will (political or otherwise) is similarly limited. And without that ability, you end up with a collection of autonomous star systems (or collections of bodies within a given system) that may or may not choose to swear allegiance to, or abide by the rules of, a notional central government. Besides, when it comes right down to it, what is the point of an interstellar government, even assuming it was feasible? What does it provide that a star system capable of participating in interstellar affairs can’t provide for itself? On a couple of more specific points. Regarding those heretics, okay you have a point. In which case just flip my original premise around and have the persecuted minority escaping a regime that regards them as heretics. Regarding megastructures vs planets - if you have the ability to build them there’s simply no contest. A tailor made, completely customisable environment without that pesky gravity well to deal that frees you from having to either find exactly the right sort of rock ball to live on or terraform (probably at even greater expense than building a megastructure) a nearly-good-enough rock ball? No, I subscribe to the Ian M Banks model, where a spacefaring, interstellar civilisation will live mostly in space rather than planet side.

I agree with @Scotius - interstellar civilizations would have literally star systems worth of room and materiel. No need to fight over either since there's plenty for everybody. Regarding religion and ideology as two other sparks for conflict, again - plenty of room for everyone. If you really, really can't stand being in the same star system as the rotten heretics, then the next star system over is probably a fine place to live. And if doesn't have any inhabitable planets? That's where O'Neil Cylinders, General Systems Vehicles (pick your sci-fi megastructure of choice) etc. come into play. But, KSK, you say. Some folks just aren't that logical or reasonable. Which is true enough. But I would also argue that organised conflict at any sort of scale requires organised societies to provide the combatants. And I would argue that organised societies at an interstellar level are functionally impossible. However they're constituted or organised, at some point they simply become too big, too unwieldy, with too many dissenting or contradictory opinions to repress or accommodate, to be viable. Not to mention the effective lack of any functional border control on an interstellar level. It's often said that there's no stealth in space. There are also no effective borders. Sooner or later, refugees will escape from even the most repressive regime. More liberal regimes probably won't even try to stop the escapees. Eventually, any sort of 'Galactic Empire' will dissolve into a loose collection of individual systems, all doing their own thing and all largely powerless to stop others doing their own thing. If you want to be pessimistic about it, there probably will be sci-fi superweapons around but MAD will ensure that they're not widely deployed.

How about two astronauts competing to put on their spacesuit gloves? That would be a proper end-of-the-arms race.

Finally got around to watching it. It was okay. Not dreadful, not great; as someone posted up-thread about Episode 2, it existed as a movie. I think that mostly it suffered from having about two films worth of stuff crammed into one. None of the plot twists had time to sow any mystery before they were conveniently solved, the emotional beats barely had time to land before something else happened to negate them. And some of the big lore dumps frankly felt like ass-pulls because they hadn’t even been hinted at in the previous films let alone foreshadowed. Much as I hate to say it as someone who actively liked The Last Jedi, the trilogy as a whole would have been better off if J.J. Abrams had just been given all three films. I suspect that we would have gotten warmed over Empire Strikes Back instead of the Last Jedi but at least it would have given Rise of Skywalker more room to breathe and would have made for a more coherent, if not especially inspired, trilogy.

SN = Spam Nuggets? Good meaty pieces of spaceflight goodness that are way cheaper than pork?

Spacepod is pretty good. Astronomy, astrophysics and uncrewed space exploration in general. Not super technical but interesting. Currently listening to Moonrise aka ‘the real reason we went to the Moon’. Which sounds a bit conspiracy theory but is actually a look at the social history and politics behind the Apollo missions. Not that far into it but it’s already thrown up a few surprises.

My God - it’s over nine thousand! And on a serious note, very glad to hear that things are still trucking along. Looking forward to reading the toe-breaker when it arrives!

Ooh - might have to look at getting that now that I’ve got a machine that’ll run it. Loved the first one.

Coming to it after having enjoyed The Last Jedi and not having been very impressed by the trailers, which seemed to be operating on a ‘drench them in fan service and hope we avoid another TLJ backlash’ basis. Am going to see it anyway because I do agree that squaring the first two films and ending the story in a coherent way looks pretty impossible, so I’m curious to see what they came up with.

That billionaire would probably be better off developing antimatter based propulsion units - as per another Spacescifi thread. Easier to hide your manufacturing facility in plain sight. "Hey, I just love particle physics alright. Why don't you all come and use my accelerator for science? Don't worry about the second storage ring over there, that's just a spare."

It'll create a 40 foot humanoid figure of pure burning plasma rage which bellows 'They thought they could contain me? FOOLS - I SHALL DESTROY THEM ALL... and their little dogs too'