Would interstellar be fun?

[Pat20999]

42 minutes ago, KSK said:

I'm willing to give it the benefit of the doubt but interstellar travel, along with multiplayer, are the parts of the KSP2 roadmap that I'm least excited about. 

For me, a lot of the appeal of KSP was the fact that it's a game about present day space exploration with present day technology, and present day limitations. Even the far end of the tech tree (as I recall) only includes technologies that have been pretty thoroughly ground tested but not actually flown (NERVA), remain a little bit speculative but one of  their key enabling systems has been built, tested, and shown to work (SABRE, which I presume RAPIER is a riff on), or are grounded in known chemistry and engineering and bits of them have been demonstrated (ISRU).

Lots of science, very little fiction.

KSP was also nicely scaled. Yes it's built around a 1/10 scale toy star system but I can mostly ignore that when I'm playing because the journey times are still approximately scaled to travel times around our own solar system. Journeys to the Mun and Minmus take days to weeks, journeys to the nearest planets take months, journeys to the more distant planets take months to years. Allowing interstellar travel - and probably repeated interstellar journeys - within the timeframe of the game, breaks that immersion and rubs my nose in the fact that I'm playing in a scaled down toy sandbox.

I also wonder about progression time within the game. KSP already suffers from that:  a brand new space program can make orbit on day 1, get to the Mun on the same day with a bit of player experience, and be heading out to the planets on the first available transfer window, or earlier if the player isn't fussed about using minimum energy trajectories. Even allowing for the fact that interstellar travel will require a bunch of infrastructure and resource mining first, I can imagine a brand new KSP2 start going interstellar within a handful of game years, which again, rather breaks the immersion for me.

Finally, I remain skeptical (to put it politely) about the feasibility of rocket-powered, crewed, interstellar travel anyway, and like @RocketRockington, I suspect that most of the challenges involved in building an interstellar craft will be abstracted away or ignored, given that a basic stock life support still seems to be a contentious issue.

In short, interstellar travel breaks a lot of what I found appealing about KSP and turns KSP2 into just another science-fiction game. That doesn't mean that roadmap complete KSP2 is going to be a bad game, but I don't believe it will have the charm of the original.  

 

 

No, the way I see it like ksp1 was always sci-fi but ksp2 does it in a more appealing way. Interstellar travel just expands colonies and is all I wanted in the first game.

[MarcAbaddon]

4 hours ago, Pat20999 said:

No, the way I see it like ksp1 was always sci-fi but ksp2 does it in a more appealing way. Interstellar travel just expands colonies and is all I wanted in the first game.

I don't think this is a matter of "the way I see it" - in KSP 1 for virtually all technology depicted we at least have advanced proof of concept (nuclear engines and RAPIER) or it is based on existing technology. The only part that feels Sci-Fi is the ISRU. The fact that spaceflight in KSP 1 is easier comes down to the lack of food and life support requirements for Kerbals and the reduced scale of the solar system. If we were living in the Kerbol system we could do all those missions at the very least using computer controlled craft.

On the other we don't know how to make interplanetary colonization work or how to travel interstellar distances. So interstellar travel and colonization definitely moves the game more into the realm of science-fiction than was the case in KSP 1, which was closer to reality. I don't think this is a matter of subjective opinions.

Personally, I don't mind that shift - you have all the science part still at the part and the interstellar part gives you something to do later in the game. And adds a few very interesting places to the game world. But that does not mean the shift doesn't exist.

[Wheehaw Kerman]

5 hours ago, KSK said:

I'm willing to give it the benefit of the doubt but interstellar travel, along with multiplayer, are the parts of the KSP2 roadmap that I'm least excited about. 

For me, a lot of the appeal of KSP was the fact that it's a game about present day space exploration with present day technology, and present day limitations. Even the far end of the tech tree (as I recall) only includes technologies that have been pretty thoroughly ground tested but not actually flown (NERVA), remain a little bit speculative but one of  their key enabling systems has been built, tested, and shown to work (SABRE, which I presume RAPIER is a riff on), or are grounded in known chemistry and engineering and bits of them have been demonstrated (ISRU).

Lots of science, very little fiction.

KSP was also nicely scaled. Yes it's built around a 1/10 scale toy star system but I can mostly ignore that when I'm playing because the journey times are still approximately scaled to travel times around our own solar system. Journeys to the Mun and Minmus take days to weeks, journeys to the nearest planets take months, journeys to the more distant planets take months to years. Allowing interstellar travel - and probably repeated interstellar journeys - within the timeframe of the game, breaks that immersion and rubs my nose in the fact that I'm playing in a scaled down toy sandbox.

I also wonder about progression time within the game. KSP already suffers from that:  a brand new space program can make orbit on day 1, get to the Mun on the same day with a bit of player experience, and be heading out to the planets on the first available transfer window, or earlier if the player isn't fussed about using minimum energy trajectories. Even allowing for the fact that interstellar travel will require a bunch of infrastructure and resource mining first, I can imagine a brand new KSP2 start going interstellar within a handful of game years, which again, rather breaks the immersion for me.

Finally, I remain skeptical (to put it politely) about the feasibility of rocket-powered, crewed, interstellar travel anyway, and like @RocketRockington, I suspect that most of the challenges involved in building an interstellar craft will be abstracted away or ignored, given that a basic stock life support still seems to be a contentious issue.

In short, interstellar travel breaks a lot of what I found appealing about KSP and turns KSP2 into just another science-fiction game. That doesn't mean that roadmap complete KSP2 is going to be a bad game, but I don't believe it will have the charm of the original.  

 

 

I agree with a lot of this - most of it, in fact, but with a caveat on a couple of points.  Done right, with the usual KSP Cartoony Verisimilitude(tm), and with consistent art style and aesthetics, I think that the tech tree can be extended further without losing the Kerbal charm.  Look at the Putt-Putt: Orion drives are about as Kerbal as you can get.

And the same goes for interstellar, although you’re absolutely right that it’ll highlight the elephant-sized hole in the room that is the absence of life support.

Edited June 3, 2023 by Wheehaw Kerman

[Pat20999]

1 hour ago, MarcAbaddon said:

I don't think this is a matter of "the way I see it" - in KSP 1 for virtually all technology depicted we at least have advanced proof of concept (nuclear engines and RAPIER) or it is based on existing technology. The only part that feels Sci-Fi is the ISRU. The fact that spaceflight in KSP 1 is easier comes down to the lack of food and life support requirements for Kerbals and the reduced scale of the solar system. If we were living in the Kerbol system we could do all those missions at the very least using computer controlled craft.

On the other we don't know how to make interplanetary colonization work or how to travel interstellar distances. So interstellar travel and colonization definitely moves the game more into the realm of science-fiction than was the case in KSP 1, which was closer to reality. I don't think this is a matter of subjective opinions.

Personally, I don't mind that shift - you have all the science part still at the part and the interstellar part gives you something to do later in the game. And adds a few very interesting places to the game world. But that does not mean the shift doesn't exist.

This whole topic is to let everyone know how they feel about the interstellar update!

[Lyneira]

On 6/3/2023 at 9:31 AM, KSK said:

In short, interstellar travel breaks a lot of what I found appealing about KSP and turns KSP2 into just another science-fiction game.

On 6/3/2023 at 2:51 PM, MarcAbaddon said:

On the other we don't know how to make interplanetary colonization work or how to travel interstellar distances. So interstellar travel and colonization definitely moves the game more into the realm of science-fiction than was the case in KSP 1, which was closer to reality. I don't think this is a matter of subjective opinions.

I do think it's important to make distinctions between different technologies that are shown in science fiction stories.

1. Technologies that we could build a physical example of and are possible with currently available materials. They might not have been used (extensively) in the real world because of scale, resources and the will to solve the engineering problems involved.
2. Unobtainium: Technologies we can't build an example of but that the laws of physics say would behave a certain way, if only we had a material with properties that we can't obtain. (yet) There are different kinds, from more grounded in science such as helium-3, metastable metallic hydrogen, antimatter and room-temperature superconductors to completely made-up materials that could, for example, have enough tensile strength to build a ringworld with.
3. Handwavium: Technologies that flat out violate the laws of physics. FTL, Time Travel and reactionless drives would fall under this.

So far, I haven't seen anything in KSP2's roadmap that falls into category 3. And of the things teased that would fall in category 2, they're materials on the science grounded side that enable more efficient engines. Unobtainium technologies like antimatter will definitely make Interstellar travel faster, but they're not required to get to another star system, it will just take more time and a larger ship.

It's true that colonization and interstellar travel are quite the unsolved problem in the real world and that the challenges of life support, crew comfort for long interstellar journeys and how to bootstrap a colony on a distant world will be glossed over a bit. But I wouldn't put interstellar travel or colonies themselves in category 2 or 3 just because we haven't solved the engineering and societal issues.

[Dakitess]

I'm fine with Engines being very very efficient ISP / Thrust wise, as long as they don't violate at all the Tsiolkovsky equation. There is nothing different between an injection from Earth to Mars and from Earth to Proxima Centauri, nothing, except that one is XX minutes duration while the other one would accelerate during whole YEARS depending on many aspects. So yeah, go ahead for 1,000,000s of ISP as long as it exactly needs a whole lot of fuel to be able to get 10% of c, which is 30km/s + the same amount to slow down at the arrival.  Because, yeah, even with that high ISP, it actually requires a LOT of fuel to move a very tiny fraction of Payload, since the engine is more than often very high in drymass.

So yeah, I belong to the "small team" saying that it's forever impossible to be able to carry a human crew in an interstellar trip, but i'm okay if we have some technologically and theoretically possible High Efficiency engines, but they really need to match the maths, not some kind of dry ratio like 25-50%, it does not work, except for antimatter. I want the payload to be very very minuscule and carefully designed, because each kilogram would equal to literal tons of added fuel to compensate. A whole challenge by itself, some kind of end-game gameplay which would cut with usual look of our tremendous overengineered vessels :p

Edited June 5, 2023 by Dakitess

[MarcAbaddon]

On 6/3/2023 at 4:18 PM, Pat20999 said:

This whole topic is to let everyone know how they feel about the interstellar update!

Yes, and whether you feel it is a good addition or not (regardless of the reasons) is completely fine. But the question of whether KSP 2 is a significant shift from established science to speculation is a subtopic that will inform the feelings of some people, i.e., in the form "I dislike interstellar, since it is not as grounded in science" is a valid contribution, stating your feeling on interstellar and the reason for your feeling. That doesn't mean the "not as grounded in science" can't be objectively true or wrong - the feeling part is more whether this has an effect on whether you like or dislike interstellar.

5 hours ago, Lyneira said:

*snip*

1. Technologies that we could build a physical example of and are possible with currently available materials. They might not have been used (extensively) in the real world because of scale, resources and the will to solve the engineering problems involved.
2. Unobtainium: Technologies we can't build an example of but that the laws of physics say would behave a certain way, if only we had a material with properties that we can't obtain. (yet) There are different kinds, from more grounded in science such as helium-3, metastable metallic hydrogen, antimatter and room-temperature superconductors to completely made-up materials that could, for example, have enough tensile strength to build a ringworld with.
3. Handwavium: Technologies that flat out violate the laws of physics. FTL, Time Travel and reactionless drives would fall under this.

*snip*

I don't completely disagree, but still  think your second category isn't cleanly separated from the third reason, and to know which technology falls into which category we'd need to be more advanced than we are.  For example, room temperature superconductors could still well violate the laws of physics. They aren't forbidden by our current theories, but we don't know whether we don't understand how to create one or whether we don't understand yet why it is impossible. One of the two is true, but we do not know which.

A lot of the technologies you list in item 3 would suddenly be possible if we found a completely-made up materials that just happened to have negative mass. 

Of course, even KSP 2 is still fairly hard science fiction in that the technologies are at least plausible, and I am not saying it has suddenly become Star Trek or Star Wars. It's probably most similar to the Expanse  before the introduction of the proto molecule - but that still means it is speculative while the older engine technology actually exists. It's a valid feeling to want KSP 2 to stick closer to established technology, even though I don't mind personally.

 

[Lyneira]

On 6/5/2023 at 4:43 PM, MarcAbaddon said:

I don't completely disagree, but still  think your second category isn't cleanly separated from the third reason, and to know which technology falls into which category we'd need to be more advanced than we are.  For example, room temperature superconductors could still well violate the laws of physics. They aren't forbidden by our current theories, but we don't know whether we don't understand how to create one or whether we don't understand yet why it is impossible. One of the two is true, but we do not know which.

You're right that categories 2 and 3 aren't cleanly separated, I read up on the terms on the Project Rho website to use them as illustration when I hastily wrote that post during a break at work. Indeed, while reading there I got some increasing doubts whether antimatter could ever work out as a fuel for the fabled antimatter engines...

To accurately portray interstellar colonization with technologies currently or nearly available to us, KSP2 would have to support ark-sized ships kilometers in size, that can support an entire biosphere slow-boating it to another star over centuries or even millennia.

[herbal space program]

On 6/6/2023 at 9:04 AM, Lyneira said:

You're right that categories 2 and 3 aren't cleanly separated, I read up on the terms on the Project Rho website to use them as illustration when I hastily wrote that post during a break at work. Indeed, while reading there I got some increasing doubts whether antimatter could ever work out as a fuel for the fabled antimatter engines...

To accurately portray interstellar colonization with technologies currently or nearly available to us, KSP2 would have to support ark-sized ships kilometers in size, that can support an entire biosphere slow-boating it to another star over centuries or even millennia.

I honestly think there is no way they can practicably implement interstellar travel in KSP2 without either introducing some sort of reality-breaking warp drive or doing what they have already done with the Kerbolar system to make the game playable, which is to scale down the distances involved  a whole lot.  That's because if they stick to any kind of realistic distance scale without a warp drive, going to a neighboring star system would immediately moot everything else you are doing inside the Kerbolar system due to the vast disparity in time scales, which I just can't see as particularly making for a good gameplay experience overall.  Of the two options for tackling that fundamental problem, I think the major scale-down is by far the most plausible.  In a tightly packed real open cluster, stars can be as close as 0.3ly apart, and if you scaled that down another 10-50 fold, roughly consistent with the Kerbolar system's downscaling, you might get that down to say 0.01-0.02ly, which would allow you to reach your destination  with something like 20 years of travel time at ~500,000 m/s.  That's still impossible with available engines, but if you posit a scaled-up 100t version of the SWERV, with an ISP of 5,000 and a thrust of 4,000-8,000kN, that moreover requires three kinds of unobtainium  to implement, say Kerbtonium 236 for a power source, Kerbomagnetic superconductors to create the reaction containment vessel, and metastable metallic hydrogen as a sufficiently compact propellant, each of which will have to be mined from a different location and refined using colony tech, I think it could occupy a unique niche in the game.  The sheer size of that engine and the difficulty of securing all its components would make it not useful for much besides implementing really large vessels for very long-distance journeys, and thus not really moot much of the existing tech for smaller-scale ventures or even exploration within the new system for that matter.  The travel times would moreover be at least on the order of magnitude of travel times in the current game. I would be very surprised for my part if what they end up doing doesn't look something like what I outlined here, but I guess time will tell!

Edited June 8, 2023 by herbal space program

[Bej Kerman]

1 hour ago, herbal space program said:

I honestly think there is no way they can practicably implement interstellar travel in KSP2 without either introducing some sort of reality-breaking warp drive or doing what they have already done with the Kerbolar system to make the game playable

...And this is being said well after they've explained the technology that lets you do this without breaking reality and with all the education resources available to us on the internet that explains how it could be done IRL.

1 hour ago, herbal space program said:

with something like 20 years of travel time at ~500,000 m/s

Okay, I think the error you've made is assuming an interstellar craft would go as slow as 500km/s. Something like 30,000km/s is closer to what you should expect.

[LunarMetis]

4 hours ago, herbal space program said:

That's because if they stick to any kind of realistic distance scale without a warp drive, going to a neighboring star system would immediately moot everything else you are doing inside the Kerbolar system due to the vast disparity in time scales, which I just can't see as particularly making for a good gameplay experience overall.  Of the two options for tackling that fundamental problem, I think the major scale-down is by far the most plausible.

I think I get where you're coming from. I'm not sure if they'll end up deciding to scale down distances between star systems, but I won't be too surprised if they do; it would be consistent with how everything else in the Kerbal universe is scaled. As for the warp drive option, I'm kinda split on whether it should be implemented. On one hand, it would indeed make traveling a whole light-year more manageable, maybe decades long if we're assuming subluminal speeds. On the other hand, it would take an extraordinary amount of energy to maintain those speeds, and I'm not sure if there would be enough available resources in the Kerbolar System to maintain a drive like that, let alone several for a colony fleet. If they decide to go with more practical technology, I'd agree that the times it'd take to travel to the nearest star systems would be way too long to derive enjoyment from. I doubt that KSP2 will add any FTL technology in any case.

Another concern I have with interstellar is how intercepting different star systems will work compared to, say, intercepting different planets' SOIs during interplanetary travel. Since there won't be a central gravitational well in interstellar space, you would basically travel in a straight line from where you exited Kerbol's SOI. Combined with the fact that other stars will apparently have simulated motion with respect to Kerbol, I imagine you would have to carefully time where exactly you exit the SOI, or you might miss the star system entirely. Alternatively, some kind of computer module that would lock the ship onto whichever star you want to travel to could be implemented in the future, though I'm not sure if that would make visiting star systems too easy, since it'd just turn into a simple point-and-click mechanic. Although I expect the latter option to be more viable than having to be really finicky with where your trajectory goes (and since this is interstellar scale, the finickiness (?) is many orders of magnitudes higher than the interplanetary scales we're used to).

However interstellar travel will play out, all I hope is that it'll find that sweet spot of long, but gratifying voyages.

[MarcAbaddon]

It's worth mentioning that our real-world speed of light is nothing magical in the KSP universe. Given that it is non-relativistic nothing like time dilation happens when you approach it and the in-game light (and radio transmission) are instantaneous instead of travelling at (our) speed of light.

The gap between the current realistic and unmodded max delta-v you achieve in KSP 1 and 10% or even 1% or even 0.1% of (our) speed of light is a lot larger than between 10% of speed of light and full speed of light. That means it is a reasonable expectation that the 'average' player is able to build a vessel that can achieve 10% of light speed, then the more experienced players would likely be able to exceed it, baring game engine troubles if you move that fast.  Which is not a problem for in game universe consistency (as it is non-relativistic), but will probably lead to a lot of somewhat silly complaints by people who prefer to have some artificial limit that matches our light of speed even if that makes the KSP universe physics inconsistent.

[KSK]

7 hours ago, Bej Kerman said:

And this is being said well after they've explained the technology that lets you do this without breaking reality and with all the education resources available to us on the internet that explains how it could be done IRL.

Okay, I think the error you've made is assuming an interstellar craft would go as slow as 500km/s. Something like 30,000km/s is closer to what you should expect.

Technology that could let you do it in theory, would be more accurate I think. Actually building that technology is a whole other flock of krakens. As always, Project Rho is my go-to site for discussing hard sci-fi spacecraft, and bluntly, I stand by my skepticism (to put it politely) about the feasibility of rocket-powered, crewed, interstellar travel. Lets take an example:

Ghost Ship

This was the winner in Project Icarus' 2013 contest to design an interstellar starship using current technology. Okay, it's a decade out of date now so we can probably assume some improvements to the numbers here but they're still... impressive. If anyone's interested in the technical details, they're all on the Project Rho website.

Specific impulse:              540,240 seconds (inertial confinement fusion engine)
Delta-V:                                 18,912,190 m/s (0.063c)
Wet mass:                             263,991 tons
Payload:                                 150 tons 

Mission profile

"Starting wet mass is 153,940,000 kg, of which 150,000,000 kg is propellant [KSK note - this is not consistent with the wet mass given above but a lower wet mass implies an even more impressive engine to get the same delta-V from less propellant.]

It accelerates for 25.63 years, reaching a velocity of 0.05c. It then coasts for 56.43 years.

Upon approaching Alpha Centauri, it deploys a magnetic sail. This drags on the interstellar medium, decelerating the spacecraft for 36 years. Once the velocity is down to 0.01c the fusion engine is used to finish the job of bringing the ship to a halt. The ship is now totally out of fuel. It then deploys lots of scientific probes and drones to gather as much scientific information as it possibly can, and transmits it back to Terra". Emphasis added.

My comments, in no particular order:

• 4 light year, one way journey, lasting about 82 years.
• Extremely high specific impulse and cruising speeds but technology seems to be consistent with the kind of thing that's planned for interstellar flight in KSP2.
• 150 ton payload is not a lot for a crew module capable of supporting that crew for an 82 year journey.
• Building this spacecraft would be an impressive endgame achievement for KSP2.  Actually flying it would be very tedious (25 year burn followed by a 56 year cruise).
• Scaling this mission concept up to handle a) crew and b) a return journey would either require an utterly absurdly large spacecraft or an extremely efficient ISRU system to harvest 150,000 tons of fusion fuel for the return journey. In any case, the round trip now becomes 164 years plus whatever time is required for refueling.

Conclusion

I stand by my original comments that "Allowing interstellar travel - and probably repeated interstellar journeys - within the timeframe of the game, breaks that immersion and rubs my nose in the fact that I'm playing in a scaled down toy sandbox" and "that most of the challenges involved in building an interstellar craft will be abstracted away or ignored."

Edit.  @MarcAbaddon makes some good points but reaching 0.1c or higher speeds using the kind of futuristic-but-plausible technology mentioned here would require a substantially larger and more implausible spacecraft. Frankly, I'm not concerned about relativistic effects or artificial speed limits because getting to those speed limits under the tyranny of the rocket equation, is already a bit silly. OK, a lot silly.

 

 

Edited June 8, 2023 by KSK

[Bej Kerman]

10 minutes ago, KSK said:

As always, Project Rho is my go-to site for discussing hard sci-fi spacecraft, and bluntly, I stand by my skepticism (to put it politely) about the feasibility of rocket-powered, crewed, interstellar travel.

You've made a few comments on it but as far as I can see you've forgotten to explain why  you think it's impossible. You can easily say "Scaling this mission concept up to handle a) crew and b) a return journey would either require an utterly absurdly large spacecraft" ^{nobody was talking about return journeys, that is absurd assuming you forego refueling and refurbishing the craft} but you never got round to doing any maths or explaining yourself.

11 minutes ago, KSK said:

"most of the challenges involved in building an interstellar craft will be abstracted away or ignored."

If it can be done in a broken-down, old game like KSP 1 (albeit extremely buggy and shoehorned into the game by several mods each of which clash with each other and the base game), without abstraction, it can be done, period.

[MarcAbaddon]

I think the burden of proof lies with people who claim interstellar distances are possible with technology that is at least somewhat close to what we have. 

Also interested to know what this is based on exactly:

8 hours ago, Bej Kerman said:

...And this is being said well after they've explained the technology that lets you do this without breaking reality

Because I don't really remember any details on that.

[KSK]

1 hour ago, Bej Kerman said:

You've made a few comments on it but as far as I can see you've forgotten to explain why  you think it's impossible. You can easily say "Scaling this mission concept up to handle a) crew and b) a return journey would either require an utterly absurdly large spacecraft" ^{nobody was talking about return journeys, that is absurd assuming you forego refueling and refurbishing the craft} but you never got round to doing any maths or explaining yourself.

If it can be done in a broken-down, old game like KSP 1 (albeit extremely buggy and shoehorned into the game by several mods each of which clash with each other and the base game), without abstraction, it can be done, period.

Sure.  To begin with though, I didn't say anything about crewed interstellar flight being impossible. I said that I was skeptical about it's feasibility. Big difference. 

As for the maths:

Given any three of:  specific impulse, wet mass, dry mass and delta-V, you can plug the numbers into the rocket equation and get the fourth number. That's easy, as I'm sure you're already aware. Given any three of:  a top speed that's a low percentage of c (so that relativistic effects can be ignored), an acceleration, a distance and a flight time, it's also straightforward to calculate the fourth number.

I'm presuming the maths presented on Project Rho is correct, since that's kind of the point of the site, although I haven't checked it personally. That's why I'm citing it as a source.  I'm also assuming that Project Rho's figures for variables such as wet mass, dry mass, ISP etc., are plausible since I have no idea how to calculate them, or even estimate them from first principles.  For the same reason, scaling up the examples given on Project Rho is beyond my ability.  For example, my gut feeling is that 150 tons is too small a payload mass to fit in a crew and all the equipment needed to keep them alive for interstellar travel times. That might be correct, or it might not be. I don't have the slightest idea what the actual mass would be, so any figure I give for it would basically be pulled from thin air. Therefore any calculations based on that mass (for fuel requirements, ship mass etc.) would effectively be pulled out of thin air too.

So I didn't bother.

But even if something is mathematically possible, that's not at all the same as doing it in practice.  For example, it's very easy to talk about a starship engine which can run continuously for 25 years. Actually, building that engine is far less easy. The same goes for almost any of the spacecraft systems - making them reliable enough to function for 80 years without maintenance, or building in enough redundancy for mission assurance over 80 years is going to be hard.  Exactly how hard, I don't know, not being an engineer, but hopefully we just can agree that it will be hard without torturing ourselves picking apart any fudged-to-heck-and-back-from-a-half-understood-Wikipedia-article  maths that I could give you.  And If you want a more detailed - and pessimistic - qualitative look at the problems of crewed interstellar travel, Project Rho has an interesting essay titled "Canned Monkeys Don't Ship Well".

But regardless of whether crewed interstellar travel is possible or plausible in real life (I have no doubt it can be done in KSP2 if it can be done in a "broken-down, old game like KSP 1") , the original point of this thread is whether it would be fun in KSP2. 

In my opinion, no for the reasons already stated. That's just my opinion though and I'm happy to agree to disagree with other folks who are looking forward to it.

Edited June 8, 2023 by KSK

[Bej Kerman]

2 hours ago, MarcAbaddon said:

I think the burden of proof lies with people who claim interstellar distances are possible with technology that is at least somewhat close to what we have. 

In that case, it lies on the British Interplanetary Society

[snip]

1 hour ago, KSK said:

Sure.  To begin with though, I didn't say anything about crewed interstellar flight being impossible. I said that I was skeptical about it's feasibility. Big difference. 

Okay, then it's probably apt to draw a specific line between feasible and infeasible.

Edited June 8, 2023 by Starhawk
Redacted by moderator

[Wheehaw Kerman]

I’ll just point to the extremely large cranes from which we suspend our disbelief over a game that lets us send Kerbals to Eeloo in craft that consist of a lawn chair strapped to an unshielded NERV.  

This is a game about spaceflight that fails to address both life support and radiation.  And we all still love it.  I’m sure we’ll be able to suspend our disbelief over however the devs implement interstellar.

[Starhawk]

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[MarcAbaddon]

39 minutes ago, Wheehaw Kerman said:

I’ll just point to the extremely large cranes from which we suspend our disbelief over a game that lets us send Kerbals to Eeloo in craft that consist of a lawn chair strapped to an unshielded NERV.  

This is a game about spaceflight that fails to address both life support and radiation.  And we all still love it.  I’m sure we’ll be able to suspend our disbelief over however the devs implement interstellar.

People being ok with Y being unrealistic does not logically follow by them being happy with X being unrealistic. There are plenty people who want life support (though this does not include me). Are you going to tell them they are wrong to want that as long as your Kerbals don't die from old age, since that would be realistic too?

[Dakitess]

These unrealistic aspect mentionned are chosen ones : the player are definitely welcome to design with some RolePlay, to give crew enough space for long duration mission, including some snacks / fret area with basic part like a tank which would weigth XX tons. This is actually how I play the game. Some people like to strap a seat on a nuke with some fuel donuts, it's fine, I don't, except sometimes for some competition, but it's a choice, you're not "supposed" to do so, you can perfectly use trusses to get some separation between your Nuke engine and you crew, or tanks, etc.

Regarding the Interstellar, otherwise... It would not be a choice to get something "too easy". Let me be clear, there is nothing like gate keeping or anything, just some balance and equilibrium for something which pretty much look like a late-game feature. It needs to be accordingly difficult and credible, to me. It's not "something else", it's not a divergent feature, another kind of gameplay, this is... Propulsion. DeltaV. Thrust. ISP. It already exists, it respects the theory, let's not break that.

So yep, a 1/10 distance compared to IRL would fit the 1/10 scale we got for the Kerbol Star System and it's fine.

It would still be something like at least 0.1 light year distance, which need a LOT of speed to get there in a generation, which means a LOT of DeltaV. It's okay to have 1,000,000s ISP engine (at most, let's not get completely out of our mind with weird exotic tech) but it still required a lot of fuel and tiny payload, or, to be more generic : tiny dry mass. I want theses vessel to be 95% fuel, 4% drymass (engines and power supply would represent a lot of mass, definitely), 1% at most for payload.

Something that we are not very used to in KSP, with usual 10-50% payload mass ratio haha. It needs to feel different, to be an achievement based on a well tought design, with sacrifices, compromises, roleplay, etc. Especially if the fuel gathering is something that get automatized and is not a real challenge by itself, once colonies are able to feed it.

So yeah, something that is like the Hard SF vessel, with good numbers that match Tsiolkovsky equation, to the very least

Edited June 8, 2023 by Dakitess

[Wheehaw Kerman]

2 hours ago, MarcAbaddon said:

People being ok with Y being unrealistic does not logically follow by them being happy with X being unrealistic. There are plenty people who want life support (though this does not include me). Are you going to tell them they are wrong to want that as long as your Kerbals don't die from old age, since that would be realistic too?

And for that matter I don’t get why people seem to mind Kerbals dying from life support issues while routinely stranding them forever or crashing them… but really, my point is that getting seriously hung up on one unrealistic aspect of a game, ignoring others, and still logging hundreds or thousands of hours is perhaps a little silly.  So long as the Interstellar implementation falls into the Kerbal Cartoony Verisimilitude(tm) zone I’m sure it’ll be fine to all but the fussiest of us.

[herbal space program]

8 hours ago, KSK said:

Edit.  @MarcAbaddon makes some good points but reaching 0.1c or higher speeds using the kind of futuristic-but-plausible technology mentioned here would require a substantially larger and more implausible spacecraft. Frankly, I'm not concerned about relativistic effects or artificial speed limits because getting to those speed limits under the tyranny of the rocket equation, is already a bit silly. OK, a lot silly.

Totally agree with that. Even getting to 0.1c will require 35 days of continuous boosting at 1g, and an engine that could do that, considering the massive amount of fuel and other mass required for an interstellar colony ship, would have to have both an absolutely ridiculous TWR and ISP at the same time, which is very out of step with how everything else in KSP works. Even the 500km/sec speeds that I was suggesting above would take something like 12 hours of continuous boosting at 1g, but at least the ship required could have 50 times less mass than one that needs to get to 0.1c, so the ISP and TWR don't have to be so completely insane. Still, simulating the physics through a boost like that is going to be a tough problem, because without doing it at a timewarp factor of 100+, it will  be way too boring to do it multiple times. They could of course just gloss over all that and put the craft on rails once you have set up the burn, but that really doesn't feel like KSP to me anymore. So unless there have been actual communications from the devs saying otherwise, I'm sticking to my theory that they are going to scale down the Kerbal galaxy a lot, and/or say that Kerbol is part of a tightly packed open cluster, or even a  loosely bound multi-star system like Mizar and Alcor, so that the distances will be on the order of 500-1000 times the distance from Kerbol to Kerbin rather than more like 100,000 times that distance. It's really hard for me to envisage how they are going to integrate the interstellar and in-system gameplay experiences otherwise.

[shdwlrd]

1 hour ago, herbal space program said:

They could of course just gloss over all that and put the craft on rails once you have set up the burn, but that really doesn't feel like KSP to me anymore.

That is their intentions. It was said that there will be unfocused burns and burns while on rails. 

Why doesn't that feel like KSP? Because they are allowing you to run multiple missions at once? (Including missions that require long burns.) 

[herbal space program]

1 hour ago, shdwlrd said:

Why doesn't that feel like KSP? Because they are allowing you to run multiple missions at once? (Including missions that require long burns.) 

It doesn't really feel like KSP to me anymore because it eliminates all pretense that you are actually flying a physical ship, i.e. it takes the physical simulation entirely out of the equation. Maybe if you have to at least start your burn under full physics before you can set it on rails it wouldn't bug me so much. The idea of having multiple missions going on at the same time OTOH doesn't really bug me at all. I've always played that way, it's just that the burns in-system are short enough (even if they take several hours)  that you don't have to have several of them happening at the same time. In any case, I'm more concerned about the implementation of ridiculously OP engines and the stark disparity in time scales brought about by  realistic interstellar distances than I am about that particular issue. I feel like they're going to have to think that one through pretty thoroughly, and to my mind the best all-around solution would be for them to scale the interstellar distances down by like something like 50-fold relative to the real neighborhood of the Sun.  As I said above, if you put Kerbol in a loosely bound multi-star system or a tight open cluster (or both even),  with everything also scaled the way the Kerbolar System itself already is, you could avoid those problems without messing with realism any more than it has already been messed with.