Generation Ships vs Cryogenic Sleep Ships

[TheBlueKerbal]

Which do you prefer?

Or what do you think you will use the most in KSP 2?

 

 

Edited January 28, 2020 by TheBlueKerbal

[mcwaffles2003]

Even sleeper ships are generation ships as crews will be required for maintaining and keeping secure those in cryostasis

Spoiler

 

most likely, IMO, neither will be part of vanilla though

Edited January 28, 2020 by mcwaffles2003

[Dirkidirk]

cryogenic sleeper ships, mostly because the existence of generation ships suggests kerbals will die of age, and nobody wants that.

Edited January 31, 2020 by Dirkidirk

[Rejected Spawn]

Just an FYI here: Kerbals don't die of age. Ever. Will not change in KSP2. Also the only confirmed multiplying of kerbals is in colonies.

Guess the thread is over already.

[mcwaffles2003]

7 minutes ago, Rejected Spawn said:

Just an FYI here: Kerbals don't die of age. Ever. Will not change in KSP2.

I agree, but what makes you that sure? We already kill them by the millions from failed launches so it cant be a "kerbals will never die" type of argument. It's not outside the possible realm

[Rejected Spawn]

Well the official stuff already informed us (at some point, not gonna dig through the mountain again) that kerbals don't die of age. Never said anything about players or krakens, isn't relevant for this thread either really since sending kerbals on interplanetary or interstellar voyages only differs significantly in how long it takes to arrive. Point being, it's officially confirmed kerbals don't die of age so the thread itself has very little meaning other than as a topic of "what mod would you make to increase the difficulty of going interstellar?"

Also I'd never install that mod, my Jeb will know eternal glory from this side of the grave.

[Xd the great]

45 minutes ago, Rejected Spawn said:

Never said anything about players or krakens

I am pretty sure that they will die of my actions.

 

1 hour ago, mcwaffles2003 said:

I agree, but what makes you that sure? We already kill them by the millions from failed launches so it cant be a "kerbals will never die" type of argument. It's not outside the possible realm

I think he means "not dying from time-wrapping too much without crashing into a planet".

[mcwaffles2003]

27 minutes ago, Xd the great said:

I think he means "not dying from time-wrapping too much without crashing into a planet".

I know that, but in the case a life support system is created, age may begin to be considered as well

[kerbiloid]

Both in one / at once. A joyship.

Have a party for 20 years, make the new generation, go sleep until the arrival and let the youngsters have their party in turn.

Upd.
Population maintenance, medical assistance & rock-n-roll.

Upd.2
Wash the plates before sleeping.

Upd 3.
And the decks.

Upd 4.
Hide the real control room until the arrival. Let them all play with mockup buttons.

Edited January 28, 2020 by kerbiloid

[mattinoz]

16 hours ago, kerbiloid said:

Upd 4.
Hide the real control room until the arrival. Let them all play with mockup buttons.

 

Do kerbals ever get to touch the real controls?

All Capsules have mock buttons anyway.

 

18 hours ago, Rejected Spawn said:

Well the official stuff already informed us (at some point, not gonna dig through the mountain again) that kerbals don't die of age. Never said anything about players or krakens, isn't relevant for this thread either really since sending kerbals on interplanetary or interstellar voyages only differs significantly in how long it takes to arrive. Point being, it's officially confirmed kerbals don't die of age so the thread itself has very little meaning other than as a topic of "what mod would you make to increase the difficulty of going interstellar?"

Also I'd never install that mod, my Jeb will know eternal glory from this side of the grave.

Sure Kerbals don't die of Age what about Boredom? clearly not in stock so fertile ground for a mod. Or aren't we allow to talk mods just yet.

Edited January 29, 2020 by mattinoz

[OOM]

Sleeping ships. Robotic control. Point.

 

Ships of generations is all nonsense. First, they are more complex, you need to create a fully reusable ecosystem. Secondly, problems with flight duration and ship reliability. Plus problems with the crew. A sleeping ship is much simpler, lighter. Only cryos technology is needed.

ps There is no sense in making interstellar flights lasting more than 100 years, which means there is no sense in a ship of generations.

Edited January 29, 2020 by OOM

[kerbiloid]

The Bureau of Interstellar Repatriation.

The XXXI century organization for collecting info about prevously launched generation and sleep ships in old archives, searching them in the sky, hyperjumping there, and delivering their passengers back to the Earth.

[Terwin]

Generation ships are the only means we currently know for certain is possible for base-line humans.

Cryo-sleep is a cool idea, but we have no idea if it will ever be possible(and even if it is, if it can be managed on a spaceship).

FTL travel is even cooler, but as of yet we don't even have any good ideas on how to attempt it.

A large ship with lots of supplies, a small crew, and a plan to procreate for future crew-members is technically feasible right now(but economically prohibitive and ethically questionable; but economics and ethics change much more readily than Physics and Biology).  Sure a sustainable closed-ecosystem would cut down on the volume of supplies needed, but that is not a requirement, just a nice-to-have.

[Okhin]

The interesting bits about the generation ships, is that, at some point, you'll have generations passing all of their life time in an artificial habitats. At some point, it does not makes sense to still speak of traveling. The ship have probably reach its cruise speed a generation ago and won't start breaking before another generation. In the meantime, people are just living their life inside what could probably be considered a permanent habitat. If you stretch the travel length a bit more, it makes no sense at all to even have a destination. The generation you live in, won't be the one reaching the planet, is not the one who left the planet, have been raised by a generation of people who also didn't left the planet and you'll raise another generation of people who won't reach a planet either, and since space is big and empty, you'll probably won't see another planetary body before long. The digital archives of the elders are now totally out of touch of your culture and it makes no sense at all, you grew more and more alien to your origin civilisation.

So, on long term scale (over 100 years of trip), building a full habitat or a spaceship becomes the same thing. And yes it have to be autonomous, you can't do resupply run when traveling in the interstellar depth and distances separating two habitable systems. You can probably harvest some stuff, but I would not count on it. Communication with homeworld becomes useless (I mean, if a message takes ten years to reach you, why does it content matters now?) and you're soon on your own. In your nice space hab, with your own culture and social determinism, without any hope of getting out of this. But then it's been your life, the life of your parents, grand parents, gran gran parents, etc …

Might just launch those habs in a random direction without any destination in mind (though it might help the first generation to get onboard of the ship).

Generation FTL ships are even weirder, because you can probably phone your grand grand grand grand parent back home, to give them the tech needed to create an habitat and send it to your position (allowing you to exist). Which might be weird and needs some spacetime paradox solving first.

BAnyway, I found this approach way funnier than the sleep ship. It's as boring as gathering money and seeking for economic stability is. Let's have a perpetual party in an artificial world and freak society instead.

[Terwin]

22 minutes ago, Okhin said:

And yes it have to be autonomous, you can't do resupply run when traveling in the interstellar depth and distances separating two habitable systems. You can probably harvest some stuff, but I would not count on it. Communication with homeworld becomes useless (I mean, if a message takes ten years to reach you, why does it content matters now?) and you're soon on your own. In your nice space hab, with your own culture and social determinism, without any hope of getting out of this. But then it's been your life, the life of your parents, grand parents, gran gran parents, etc …

Even if you have a 100% recyclable system, you will still need energy inputs, and interstellar space in not a great place for sonar panels, so your vessel will have a finite duration unless you have some new sort of inexhaustible energy(ie a perpetual motion machine).

If you have a finite duration, then you can have a less than 100% recyclable life-support system, you just need to bring replacements/supplies to replace the losses for the expected duration.   (This is true even for a 0% recyclable life support system).

You will still probably want access to news and entertainment from your home-base and/or destination, and this will help maintain cultural familiarity, even if not similarity.

Also, some vessels will be making round trips(you can't expect the first crews to alpha-centari to just die if there is not an immediately habitable planet for example), so while the cultures may well drift apart, they will also have the opportunity to drift back together(although ships that only need to be viable for 1-2 generations before returning home could probably get away with half a dozen or less crew, and at that point you don't have a lot in the way of your own culture compared to the hundred+ channels of media being streamed to you from earth)

[shdwlrd]

Cryo ship, put them to sleep so you don't have to entertain them for decades. 

[Okhin]

@Terwin Well, it's already hard for us to keep track of what's happening 200km away. Even with real time news, you'll have to filter. If you have ten year lags (and it keeps rising), I do not know at which point people eventually give up on keeping tabs about what's happening home. They'll have enough stuff to keep track of around them, anything that's not a major event will probably be see as futile. And outdated: it happened ten years ago, if they publish a reaction, they'll get it twenty years after the event. A little bit like if we would receive next year a message saying "Sorry for your losses on this 9/11 day". It would be out of touch, even for us.

And I really think it's easier to build a ship which can scavenge whatever lies around than planning for a return trip. I mean, even if we can reach 0.2c, going to Alpha Centaurii is still at least twenty years. So you want to be as self sustainable as possible (and I know, nothing really is). So going there and back is fourty years. At best (not counting looking for stars and first try at colonization, which might take a decade before abandoning it), roughly two generation. If you pack everything from the start, it's going to be a tough start. Refueling it means going faster than the mother ship, and we're already at 0.2c (which already seems way below our tech level), why not, but then you're energy budget is sky rocketing (well, a bit like your ship anyway).

So yes, as I see it, a ship which have for destination another star system, must be either fully-automated (we're not sending people there), or an as autonomous of an habitat as possible. With it's own spaceport facility to allow for scouting and harvesting missions (so, your generation ship needs its own space program, and will probably send people scouting and harvesting on year long mission to gather the volatile organics compounds needed for sustaining the habitat).

If it takes less than one generation to go there due to technology, well then the issue is settled, you need neither sleep or generation, you need a colonization expedition.

[Rejected Spawn]

Any of you ever have one of those moments when there's a bunch of strangers talking about stuff and they just keep saying things that are based on completely skewed theories and make assumptions that large sections of the populace thinks are correct but you happen to know loads of evidence that disproves it all right at the root? I'm having SO much of that moment right here. Don't get me wrong, I like the musings about what interstellar human voyages could look like but I feel itchy all over just observing the mountains of outdated arguments being used.

The biological side of it, Part One: We are highly unlikely to be able to come back to life after getting turned into meat popsicles. Our cells just don't work that way, the biggest problem is that the water that is actually the majority of our body mass turns into sharp crystals that cut our cells to ribbons - but even if that somehow gets solved against all odds there are other molecular structures inside us that don't take well to getting frozen. Getting around all the limits of our own bodies would mean modifying every cell in our bodies to somehow get through being frozen - but would such an organism even be called human at that point? More like some remote sub species that (presumably still) resembles humans.

Biology Part Two: Guess you fellows don't check out much science that isn't about rockets, however there have been some major breakthroughs in figuring out why and how we age down on the molecular level, our life expectancy is quite possibly about to jump sky high and closely match that of Kerbals and we would easily live for multiple centuries - as long as our stupidity doesn't get to us first. Those who are interested in finding out more can check this video that does an adequate job of explaining it so the average person can easily understand; https://youtu.be/QRt7LjqJ45k Do note however that this isn't even the only stuff going on in the field.

Ship travel speed: I'm gonna have to call absolute scifi daydreaming on anything close to lightspeed. Having spent a bit of time working on my own projects in physics over the past 15 years (mainly investigating particle physics) I've come to learn that a lot of widely accepted physics "stuff" is solid if you only look at the math - but the numbers and their formulas are coming from far too little observational data (sometimes essentially none at all) to have any relevance outside of pure speculation. I've yet to see anyone other than myself easily and immediately explain why identical particles accelerated to identical speed end up with different mass depending on the type of particle accelerator used, though I've given up on waiting for others to wrap their heads around that one so maybe someone else has finally noticed by now and I'll be pleasantly surprised one day. Getting back to the "travel speed" I'm calling complete fantasy on moving at any speed too high to survive colliding with stray atoms (plenty of those all over interstellar space) and any ship unable to detect and dodge (or push aside/obliterate with 1337 lazorzzz) any bigger obstacles in its way. "But we rarely hit anything at all in space, we have thousands of satellites doing fine?" Well those are tiny, our ship would have to be several orders of magnitude bigger and get through a mind blowing volume of space.

Ship travel time: Since we won't be going extremely fast unless we want to die extremely fast the ship MUST have its own recycling system on an unprecedented scale, I've been saying a related thing for some time - "By the time we can reach planets in other solar systems, we no longer need planets at all." - because the immense scale of an interstellar ship and the mad timeframe involved make it ridiculous to get adamantly hung up on landing somewhere instead of just living on the ship perpetually. We'd be better off just migrating to a gigantic space station in the first place, hang out in nice scenic spots around this local star until it starts getting iffy and then pack up the entire station and migrate to the next star. By then the station might give the Death Star a real challenge in terms of size.

Ship energy source: We're not getting anywhere until we have reliable fusion power. Most of you probably know the long running joke of fusion always being "20 years in the future" but some proper big steps based on proper modern science have made the statement far less of a joke and way more of a realistic estimate. I'm still sceptical regarding the immediate energy released from a fusion reaction being absorbed well enough to sustain the reaction the way they're going about it since there is so much waste heat leeching away, however there's a lot of room for another piece of tech to save the day there - conversion of pure thermal energy into electricity. We already know that infrared light (heat radiation) can be absorbed and converted to usable power by certain advanced solar cells, it's only a matter of the efficiency being too low to make economical sense so far. There have also been some interesting other concepts such as nano antennas that succeeded in capture of heat and generation of an electric current, though it was far too costly to develop the stuff needed to efficiently extract the current. Seeing how we've already had multiple unrelated techs proving the conversion of heat directly to electricity is possible I'd bet quite a bit we'll have some relatively potent stuff by the time that fusion reactor becomes more of an everyday thing. As for the fuel, we only need to occasionally pick up some to keep the reactor firing every now and then. We don't need to keep it on at all times if we manage to recycle most waste heat aboard the ship.

So yeah hey there Star Theory, if you want a particle physics backseat driver telling you a bunch of random crazy not-rocket-centric stuff you know where to find me. \o/

[mattinoz]

15 minutes ago, Rejected Spawn said:

...

So yeah hey there Star Theory, if you want a particle physics backseat driver telling you a bunch of random crazy not-rocket-centric stuff you know where to find me. \o/

Now my head hurts...I'm going to be coming back and rereading this all weekend.

[mcwaffles2003]

17 hours ago, Rejected Spawn said:

I've yet to see anyone other than myself easily and immediately explain why identical particles accelerated to identical speed end up with different mass depending on the type of particle accelerator used, though I've given up on waiting for others to wrap their heads around that one so maybe someone else has finally noticed by now and I'll be pleasantly surprised one day. 

BS in physics and chemical physics here, may I know the context of this a bit more? Like the types of accelerators (guessing linear vs ring) and are the targets the same? Also I saw that veritasium vid too, like how he talked about epigenetics and ruled out telemeres, been looking into longetivity research a bit over the past 5 or so years. 

 

Also with modern ideas around cryogenic hibernation I believe doesn't necessitate freezing, I believe you can induce a severe hypothermia and hold someone's body in near stasis essentially bringing the metabolism to nearly but not completely inactive. 

EDIT: BS not BA

Edited January 31, 2020 by mcwaffles2003

[Incarnation of Chaos]

Spoiler

4 hours ago, Rejected Spawn said:

Any of you ever have one of those moments when there's a bunch of strangers talking about stuff and they just keep saying things that are based on completely skewed theories and make assumptions that large sections of the populace thinks are correct but you happen to know loads of evidence that disproves it all right at the root? I'm having SO much of that moment right here. Don't get me wrong, I like the musings about what interstellar human voyages could look like but I feel itchy all over just observing the mountains of outdated arguments being used.

The biological side of it, Part One: We are highly unlikely to be able to come back to life after getting turned into meat popsicles. Our cells just don't work that way, the biggest problem is that the water that is actually the majority of our body mass turns into sharp crystals that cut our cells to ribbons - but even if that somehow gets solved against all odds there are other molecular structures inside us that don't take well to getting frozen. Getting around all the limits of our own bodies would mean modifying every cell in our bodies to somehow get through being frozen - but would such an organism even be called human at that point? More like some remote sub species that (presumably still) resembles humans.

Biology Part Two: Guess you fellows don't check out much science that isn't about rockets, however there have been some major breakthroughs in figuring out why and how we age down on the molecular level, our life expectancy is quite possibly about to jump sky high and closely match that of Kerbals and we would easily live for multiple centuries - as long as our stupidity doesn't get to us first. Those who are interested in finding out more can check this video that does an adequate job of explaining it so the average person can easily understand; https://youtu.be/QRt7LjqJ45k Do note however that this isn't even the only stuff going on in the field.

Ship travel speed: I'm gonna have to call absolute scifi daydreaming on anything close to lightspeed. Having spent a bit of time working on my own projects in physics over the past 15 years (mainly investigating particle physics) I've come to learn that a lot of widely accepted physics "stuff" is solid if you only look at the math - but the numbers and their formulas are coming from far too little observational data (sometimes essentially none at all) to have any relevance outside of pure speculation. I've yet to see anyone other than myself easily and immediately explain why identical particles accelerated to identical speed end up with different mass depending on the type of particle accelerator used, though I've given up on waiting for others to wrap their heads around that one so maybe someone else has finally noticed by now and I'll be pleasantly surprised one day. Getting back to the "travel speed" I'm calling complete fantasy on moving at any speed too high to survive colliding with stray atoms (plenty of those all over interstellar space) and any ship unable to detect and dodge (or push aside/obliterate with 1337 lazorzzz) any bigger obstacles in its way. "But we rarely hit anything at all in space, we have thousands of satellites doing fine?" Well those are tiny, our ship would have to be several orders of magnitude bigger and get through a mind blowing volume of space.

Ship travel time: Since we won't be going extremely fast unless we want to die extremely fast the ship MUST have its own recycling system on an unprecedented scale, I've been saying a related thing for some time - "By the time we can reach planets in other solar systems, we no longer need planets at all." - because the immense scale of an interstellar ship and the mad timeframe involved make it ridiculous to get adamantly hung up on landing somewhere instead of just living on the ship perpetually. We'd be better off just migrating to a gigantic space station in the first place, hang out in nice scenic spots around this local star until it starts getting iffy and then pack up the entire station and migrate to the next star. By then the station might give the Death Star a real challenge in terms of size.

Ship energy source: We're not getting anywhere until we have reliable fusion power. Most of you probably know the long running joke of fusion always being "20 years in the future" but some proper big steps based on proper modern science have made the statement far less of a joke and way more of a realistic estimate. I'm still sceptical regarding the immediate energy released from a fusion reaction being absorbed well enough to sustain the reaction the way they're going about it since there is so much waste heat leeching away, however there's a lot of room for another piece of tech to save the day there - conversion of pure thermal energy into electricity. We already know that infrared light (heat radiation) can be absorbed and converted to usable power by certain advanced solar cells, it's only a matter of the efficiency being too low to make economical sense so far. There have also been some interesting other concepts such as nano antennas that succeeded in capture of heat and generation of an electric current, though it was far too costly to develop the stuff needed to efficiently extract the current. Seeing how we've already had multiple unrelated techs proving the conversion of heat directly to electricity is possible I'd bet quite a bit we'll have some relatively potent stuff by the time that fusion reactor becomes more of an everyday thing. As for the fuel, we only need to occasionally pick up some to keep the reactor firing every now and then. We don't need to keep it on at all times if we manage to recycle most waste heat aboard the ship.

So yeah hey there Star Theory, if you want a particle physics backseat driver telling you a bunch of random crazy not-rocket-centric stuff you know where to find me. \o/

 

Any ship that's large enough to house a self-sustaining ecology, crew and power its self i'd imagine wouldn't be hard pressed to sheathe itself in plasma; though that only helps against physical debris. The biggest issue with anything approaching light speeds is that everything in front of you is getting blue-shifted into immensely powerful gamma radiation. Which i do think will be the hard limit for quite some time, as the only solution is mass. And with the energies involved; bremsstrahlung radiation would almost be certain even if you had enough lead/iridium/osmium to absorb it.

But if you could find some way to create energy from gamma radiation? This could actually be turned to your advantage, but that's going into the realm of science fantasy to be honest.

But speeds approaching 30-40% C i don't think would be that difficult assuming you have fusion power, and are able to generate a plasma bubble around the ship.

As for Cryogenics; i'm actually completely agreed here. The classical form isn't even remotely possible; heck i can tell the difference between frozen and fresh meat because of how much damage the ice crystals to do the tissues. I don't even know why anyone would think that it would be viable for humans. However; you mention radical life extensions are becoming very possible which leads to my second point.

3 hours ago, mcwaffles2003 said:

Also with modern ideas around cryogenic hibernation I believe doesn't necessitate freezing, I believe you can induce a severe hypothermia and hold someone's body in near stasis essentially bringing the metabolism to nearly but not completely inactive. 

While classical human-cicles aren't possible; with radical life extension and genetic modification you could get something very close by using the methods described above. You could also replace the blood with something else that's fairly inert but carries oxygen; though that's something that would have to be developed further. If you had someone in a hypothermic state; with inert oxygen-containing blood replacements in a hypoberic chamber filled with argon or another noble gas then combined with the life extension and other genetic modifications you could reduce the dry mass for keeping the crew alive signifigantly.

And for the whole "Why would you want to settle planets when you can do everything in space"; i'd say while it is a good point it also overlooks that planets are just a much better enviroment with less risk. Sure a massive habitat wouldn't be that far off of a planet, but there's so many things you have to worry about that are just gone the moment you're planetside.

On a habitat you have to create some kind of simulated gravity, bring all your breathing gas, all the soil and any life and you have to maintain it. That's before we even consider that the all-consuming void is only a few feet from you at any point, and makes transferring all of this heat you're generating much harder.

So to me it makes more sense for any first expedition to start out on a planet; then build upward. Now when you're at the point where you have fusion powered von neumann machines that could build all of this for you hundreds of years before you even arrive? Then yeah; space habitats win. But even then we're incredibly vain things, so i wouldn't be surprised if planets were settled just for the experience of being on one. Kinda like tourism today.

[kerbiloid]

Option #3.

Meditation ship.

Get immortal and enjoy the travel.

Upd.
Wait... KSP.

Upd 2.
The ship must stay intact for millions of years.
As a mechanical ship can not repair itself so long, then you need an instantly regenerating immortal bioship.

Upd 3.
Wait...
As both ship and you are not humans anymore, then be the ship yourself.
So, let's welcome the infinite era of sapient interstellar space whales.

Upd .final

Spoiler

 

Edited January 31, 2020 by kerbiloid

[mcwaffles2003]

22 minutes ago, kerbiloid said:

Option #3.

Meditation ship.

Get immortal and enjoy the travel.

Upd.
Wait... KSP.

Upd 2.
The ship must stay intact for millions of years.
As a mechanical ship can not repair itself so long, then you need an instantly regenerating immortal bioship.

Upd 3.
Wait...
As both ship and you are not humans anymore, then be the ship yourself.
So, let's welcome the infinite era of sapient interstellar space whales.

Upd .final

  Reveal hidden contents

 

then we can orbit close to black holes as our minds are transferred to computers and watch the universe pass in moments as special relativity from the gravity well bends time for all of us and we can finally die in peace as the universe undergoes heat death

[Klapaucius]

On 1/29/2020 at 7:44 PM, mattinoz said:

Sure Kerbals don't die of Age what about Boredom? 

I think Kerbals have evolved an amazing capacity to just zone out. Mix that with genetics similar to those frogs that can freeze solid and thaw out again (explains the green pigment) and you have a species designed for space travel.

[Rejected Spawn]

  

8 hours ago, mcwaffles2003 said:

BA in physics and chemical physics here, may I know the context of this a bit more? Like the types of accelerators (guessing linear vs ring) and are the targets the same? --

Wow it makes me kind of happy to have someone around who gets this stuff.  Sorry to say I can't elaborate on it too much just yet, I have to keep my big mouth shut about a lot of details for a few more months in order to capitalize on the insights a little first. Let's both keep our fingers crossed nothing goes wrong and I'm able to finish at least one of my prototypes, my budget is terrible and some of this stuff is pretty dangerous but I've finally got both a modified CR10 S5 (capable of printing polycarbonate, wohoo!) and a CR10 MAX (for much better accuracy of general support parts) to help me create the bits and bobs needed so I should be able to get some solid data with very minimal risk of electrocution, explosion or fire. Stay tuned and hopefully I'll appear on youtube with results!

As for cryostasis I'll touch on it a little again below... 

5 hours ago, Incarnation of Chaos said:

  Reveal hidden contents

 

Any ship that's large enough to house a self-sustaining ecology, crew and power its self i'd imagine wouldn't be hard pressed to sheathe itself in plasma; though that only helps against physical debris. The biggest issue with anything approaching light speeds is that everything in front of you is getting blue-shifted into immensely powerful gamma radiation. Which i do think will be the hard limit for quite some time, as the only solution is mass. And with the energies involved; bremsstrahlung radiation would almost be certain even if you had enough lead/iridium/osmium to absorb it.

But if you could find some way to create energy from gamma radiation? This could actually be turned to your advantage, but that's going into the realm of science fantasy to be honest.

But speeds approaching 30-40% C i don't think would be that difficult assuming you have fusion power, and are able to generate a plasma bubble around the ship.

As for Cryogenics; i'm actually completely agreed here. The classical form isn't even remotely possible; heck i can tell the difference between frozen and fresh meat because of how much damage the ice crystals to do the tissues. I don't even know why anyone would think that it would be viable for humans. However; you mention radical life extensions are becoming very possible which leads to my second point.

While classical human-cicles aren't possible; with radical life extension and genetic modification you could get something very close by using the methods described above. You could also replace the blood with something else that's fairly inert but carries oxygen; though that's something that would have to be developed further. If you had someone in a hypothermic state; with inert oxygen-containing blood replacements in a hypoberic chamber filled with argon or another noble gas then combined with the life extension and other genetic modifications you could reduce the dry mass for keeping the crew alive signifigantly.

And for the whole "Why would you want to settle planets when you can do everything in space"; i'd say while it is a good point it also overlooks that planets are just a much better enviroment with less risk. Sure a massive habitat wouldn't be that far off of a planet, but there's so many things you have to worry about that are just gone the moment you're planetside.

On a habitat you have to create some kind of simulated gravity, bring all your breathing gas, all the soil and any life and you have to maintain it. That's before we even consider that the all-consuming void is only a few feet from you at any point, and makes transferring all of this heat you're generating much harder.

So to me it makes more sense for any first expedition to start out on a planet; then build upward. Now when you're at the point where you have fusion powered von neumann machines that could build all of this for you hundreds of years before you even arrive? Then yeah; space habitats win. But even then we're incredibly vain things, so i wouldn't be surprised if planets were settled just for the experience of being on one. Kinda like tourism today.

Regarding that plasma bubble, I'm gonna simplify the math a little and boil it down to what matters for those who may be interested but not *super* interested. First of all; some kind of non solid shield around the ship would be 100% essential for survival, we could get wiped out before even making it past the moon if we didn't have that since space does have tiny debris all over the place and the debris by itself is moving at deadly speeds. Let's look at what kinds of speeds we're talking about for the ship then. The speed of light with a bit of rounding is 300.000.000m/s. The speed of sound in our thick atmosphere is about 343m/s. When we fire a rifle bullet that travels at the speed of sound, that thing gets pretty gosh darn far and is still rather deadly. Increasing the speed of the bullet means it's going to break apart - higher speeds make it break apart more, but it will keep posing a major threat for a very long distance no matter what. Reach a high enough speed and the bullet essentially vaporizes in a microsecond but the individual atoms (or even ions) will still be travelling a very substantial distance and rip apart anything in their path as well as create a massive shockwave and releasing immense heat. Taking the speed up to just 1% of the speed of light, this bullet is going to be so deadly it's not even funny. That's in our thick atmosphere. How dense and big would the cloud of gas or plasma have to be to shield our precious ship from the impact of something like that? Don't ask me, I'm not interested enough to do the math properly to be honest, however using any ballpark estimate we probably all conclude that it would have to be impossibly huge, way beyond what seems to be within the realm of what we can build any decade soon. Interstellar space isn't empty, there will be pebbles far bigger than a meek bullet out there and we're more than a little likely to hit one dead on. My take on this is that we just won't be going anywhere all that fast. On a related sidenote, everyone keeps asking why the aliens that should be out there haven't come over to play... yeah, they probably like being alive and won't be going interstellar unless they have to for survival reasons.

I'm in agreement that planets solve a number of issues but don't forget that they also come with other issues instead. Any planet that has an atmosphere is most likely a toxic wasteland, any that doesn't have one is not going to provide much better shielding against radiation and space debris than if you were on a space station, it just limits how many directions you can get hit from. Sitting on a planet means that if there is an asteroid heading for it you have no choice but to drop everything and evacuate, a space station however is both a smaller target and can just get out of the way if need be. Now if we presume we find a planet like earth, it doesn't have terrible atmosphere and it has all the good stuff we liked about this ball of dirt, it may also have life on it... Does that mean we're better off or worse off? Probably worse off. If any complex life has evolved in a similar fashion to earth life there's a high probability some of this life will be bacterial, viral, parasitic or severely toxic - in an alien fashion that our bodies have never evolved to handle. There are tribes of humans on earth that can't be contacted because they'd likely die from exposure to the bacterial and viral evolution that's been going on in the rest of the worlds population, their immune system is just outdated by hundreds of generations... imagine your immune system being many times worse off than that. Our best planetary bet is to claim a guaranteed dead world, terraform it over a huge span of time and then hope we can stay there without any issues. Compared to that I think a colossal space station where hundreds of millions of us live in comfort and safety sounds like a much better idea. Keep in mind that the station might as well be as big as we can possibly make it, if we have the waste heat problem covered the upper size limit skyrockets.

Regarding non frozen cryostasis, there are loads of things in our blood other than oxygen carriers and immune cells, this video by Kurzgesagt covers a bit of the complexity involved: https://youtu.be/BSypUV6QUNw (good channel, usually almost completely objective, does inject opinion in some topics though so take those with a bucket of salt) Moving further from regular cells we are also home to a huge amount of bacteria that are essential to our health, if we modify our bodies and become an unsuitable home for them, there is substantial risk it will greatly affect our health. If you take an interest here's a rather amusing Joe Scott video on the topic: https://youtu.be/iytAHXo2_V8 Anyway I'd say cryostasis (as a broad term including just "chilling out") is way too dangerous to get into any decade soon, there are far too many factors that we know far too little about to safely mess with. I'd strongly prefer simply staying awake playing tetris for a thousand years instead of taking a potentially deadly powernap on the way over to the nearest star.

Edited January 31, 2020 by Rejected Spawn
Dun goof'd the quotingthingading.