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I am more worried about my potential grandchildren making it to the end of the 21st century against climate change, environmental degradation and the decline of the post-WW2 international rules based order, than I am about a possible dinosaur killer asteroid.

Besides, there are other cosmic extinction events we have no chance of preventing, such as gamma ray bursters.

 Kilkrazy wrote:
I am more worried about my potential grandchildren making it to the end of the 21st century against climate change, environmental degradation and the decline of the post-WW2 international rules based order, than I am about a possible dinosaur killer asteroid.

Besides, there are other cosmic extinction events we have no chance of preventing, such as gamma ray bursters.

But those can be avoided by leaving the solar system. Which we can't do until we both find somewhere plausible to go, and have extensive experience constructing ships and colonies. The latter of which we can't get if we sit on Earth twiddling our thumbs while drones potter around the solar system(besides which, drone exploration has limits - even Mars is pushing it due to the coms delay, and regardless of how "illogical" it is most people find human exploration inspiring and aspirational which helps drive interest in and funding for science, while "we landed some rovers" will only stir the passions of existing space-nerds - while there is no binary choice between space and the military in theory, in practice people are not bloody robots and if you want them to support spending tax money on scientific endeavour they have to see and feel the "endeavour" part, and space exploration does that better than anything else).

Contrary to what Peregrine evidently believes, colonising Mars is not just sending half a dozen folk up there to sit in a bubble, it's a proof of concept for the idea we can establish ourselves permanently and sustainably on another world, and importantly one that is not at present particularly hospitable to us(ie, the kind of world we're far more likely to find Out There than perfect wee goldilocks worlds like Earth). Further, colonising Mars will likely require us to innovate solutions that firmly apply to your more immediate concerns - it's becoming more and more likely that the only plausible way to address climate change and environmental collapse will be geo-, atmo-, and bio-engineering(yes yes, I'm sure Peregrine will just say "but we could just not pollute stuff", but back in Reality Land...), all sectors of research that would receive a huge influx of interest and funding for the planning stages of a terraforming effort for Mars.

Which is why manned space exploration is more valuable, in my view, than "targeted research", because you can only target something if you know what it is already, whereas manned space exploration often requires people to solve problems we don't have on Earth yet but may in the future(by which time developing the knowledge would come too late to be of much use), or to solve problems in new ways that might not otherwise have occurred for years or decades or ever at all. All of the same arguments that apply to pure-theory physics research(without which we never would have developed such piffling ideas as microelectronics...) apply to manned space exploration.

7 billion people can't leave the solar system by the end of the century.

It's not about getting 7 billion people out. It's about spreading the species, and in the process, learn about creating and maintaining a planetary ecosphere without risking the entire species while we figure out what doesn't work beyond what's already ostensibly not working on Earth.
Knowledge that is, or will be, sorely needed as unbridled population growth screws up our currently only planet and the current economic/political climate almost completely fails to address either the cause or its consequences.

Someone had a line in their sig once, it read "The galaxy is littered with the single-planet graveyards of species that made the economically sensible decision not to explore space."

Bran Dawri wrote:
It's not about getting 7 billion people out. It's about spreading the species, and in the process, learn about creating and maintaining a planetary ecosphere without risking the entire species while we figure out what doesn't work beyond what's already ostensibly not working on Earth.
Knowledge that is, or will be, sorely needed as unbridled population growth screws up our currently only planet and the current economic/political climate almost completely fails to address either the cause or its consequences.

We're not going to invent hyperdrive, find dozens of new inhabitable planets, inhabit them, ruin them, finally realise what we already know about ruining the Earth with pollution and so on, and then inhabit some more planets and not ruin them, by the end of the century.

 Kilkrazy wrote:

Bran Dawri wrote:
It's not about getting 7 billion people out. It's about spreading the species, and in the process, learn about creating and maintaining a planetary ecosphere without risking the entire species while we figure out what doesn't work beyond what's already ostensibly not working on Earth.
Knowledge that is, or will be, sorely needed as unbridled population growth screws up our currently only planet and the current economic/political climate almost completely fails to address either the cause or its consequences.

We're not going to invent hyperdrive, find dozens of new inhabitable planets, inhabit them, ruin them, finally realise what we already know about ruining the Earth with pollution and so on, and then inhabit some more planets and not ruin them, by the end of the century.

Not with that attitude.

 Yodhrin wrote:
All that said, if we decide to allow corporations to go off and stripmine the solar system(and we bloody well shouldn't)...

Out of curiousity... why not? Would you rather they stripmine the earth, with all the ecological damage that entails? I would think it to be better to stripmine lifeless bodies rather than wreck the one body with a functioning ecosystem we can survive in...

 Vulcan wrote:
Out of curiousity... why not? Would you rather they stripmine the earth, with all the ecological damage that entails? I would think it to be better to stripmine lifeless bodies rather than wreck the one body with a functioning ecosystem we can survive in...

I think the point is to not allow companies in general to unilaterally decide what to stripmine because if left unchecked they'll go beyond what is sustainable in the name of profit, no matter the consequences or externalities.

Even so that "lifeless body" (the moon), has an impact on life on earth, no matter what Bill O’Reilly says.

If I remember correctly there are already some plans for private space mining that are looking for suitable asteroid. Usually bigger visitors that appear occasionally. The idea is to extrapolate their next visit near earth, shoot mining equipment into space to meet them, mine some stuff, and when they get near earth jump off and get back to earth with the loot.

 Kilkrazy wrote:

Bran Dawri wrote:
It's not about getting 7 billion people out. It's about spreading the species, and in the process, learn about creating and maintaining a planetary ecosphere without risking the entire species while we figure out what doesn't work beyond what's already ostensibly not working on Earth.
Knowledge that is, or will be, sorely needed as unbridled population growth screws up our currently only planet and the current economic/political climate almost completely fails to address either the cause or its consequences.

We're not going to invent hyperdrive, find dozens of new inhabitable planets, inhabit them, ruin them, finally realise what we already know about ruining the Earth with pollution and so on, and then inhabit some more planets and not ruin them, by the end of the century.

No, but you're well on the way to inventing the hyperbole drive it seems

Inhabiting Mars in the near future is not about solving all of our problems and achieving world peace and ensuring free orgasms five times a day all by the end of the decade, it's a necessary first step in a process designed to ensure the survival of humanity in the very long term which could, as a side benefit, provide us with useful knowledge and technology that can contribute to solving present day issues.

 Vulcan wrote:

 Yodhrin wrote:
All that said, if we decide to allow corporations to go off and stripmine the solar system(and we bloody well shouldn't)...

Out of curiousity... why not? Would you rather they stripmine the earth, with all the ecological damage that entails? I would think it to be better to stripmine lifeless bodies rather than wreck the one body with a functioning ecosystem we can survive in...

Oh I've not problem with extracting resources from the solar system, especially the asteroid belt. I just think that the exploration and, where appropriate, exploitation of space should benefit humanity, not a handful of already ludicrously wealthy billionaires and their cronies. If we run space mining like countries used to run oil(ie, public companies as well as private, private pay tax out of every damned orifice and maybe get a few extra poked in them for good measure, and we regulate the gak out of it) then hi ho hi ho, but if it's just going to be Shell and the Kochs etc going out and carrying right on as they are now why even bother.

 Yodhrin wrote:

 Kilkrazy wrote:
I am more worried about my potential grandchildren making it to the end of the 21st century against climate change, environmental degradation and the decline of the post-WW2 international rules based order, than I am about a possible dinosaur killer asteroid.

Besides, there are other cosmic extinction events we have no chance of preventing, such as gamma ray bursters.

But those can be avoided by leaving the solar system

This is so insanely betond our abilities it is scarcely worth considering as a distant possibility over the course of millennia.

nfe wrote:

 Yodhrin wrote:

 Kilkrazy wrote:
I am more worried about my potential grandchildren making it to the end of the 21st century against climate change, environmental degradation and the decline of the post-WW2 international rules based order, than I am about a possible dinosaur killer asteroid.

Besides, there are other cosmic extinction events we have no chance of preventing, such as gamma ray bursters.

But those can be avoided by leaving the solar system

This is so insanely betond our abilities it is scarcely worth considering as a distant possibility over the course of millennia.

Which is I'm sure exactly what people said about concepts such as flight a few hundred years ago. Or going into space at all.

There will always be naysayers, there will always be optimists and there will always be people getting stuff done.

 An Actual Englishman wrote:

nfe wrote:

 Yodhrin wrote:

 Kilkrazy wrote:
I am more worried about my potential grandchildren making it to the end of the 21st century against climate change, environmental degradation and the decline of the post-WW2 international rules based order, than I am about a possible dinosaur killer asteroid.

Besides, there are other cosmic extinction events we have no chance of preventing, such as gamma ray bursters.

But those can be avoided by leaving the solar system

This is so insanely betond our abilities it is scarcely worth considering as a distant possibility over the course of millennia.

Which is I'm sure exactly what people said about concepts such as flight a few hundred years ago. Or going into space at all.

No. They didn't really. People long thought flight was an achievable goal with sufficient technology. They had seen things fly, after all. It is not the same as inventing relativistic travel and mastering generation ships. We're talking about upturning physics for the former, not the fairly minor improvements in engineering that allowed us to stay off the ground and then go higher.

 An Actual Englishman wrote:
Which is I'm sure exactly what people said about concepts such as flight a few hundred years ago. Or going into space at all.

There will always be naysayers, there will always be optimists and there will always be people getting stuff done.

Only ignorant people said that about flight. Anyone with any sense saw that birds could fly, and human flight was just an engineering problem to solve. Any skepticism from informed experts was limited to the difficulty of finding an engine with a good enough power to weight ratio before 1900. See https://en.wikipedia.org/wiki/George_Cayley getting all of this figured out ~100 years before the first powered flight.

Contrast this with leaving the solar system and colonizing other planets, where the difficulties are well known to be effectively impossible and a direct result of basic laws of physics, no example of successful interstellar travel exists to prove that it can be done, and no plausible theory for how it could work is even under consideration. Short of a complete revolution in physics that overturns everything we know there is no clever solution that makes the time or energy requirements less of an obstacle. It is always going to be obscenely expensive and difficult to send anything outside the solar system, and there's no realistic scenario where we find a purpose for the trip that justifies the cost.

Wouldn't surprise me if we NEED to experience a near-extinction level event before we sort our collective gak out and do something to avoid a repeat.

 Yodhrin wrote:

 Kilkrazy wrote:

Bran Dawri wrote:
It's not about getting 7 billion people out. It's about spreading the species, and in the process, learn about creating and maintaining a planetary ecosphere without risking the entire species while we figure out what doesn't work beyond what's already ostensibly not working on Earth.
Knowledge that is, or will be, sorely needed as unbridled population growth screws up our currently only planet and the current economic/political climate almost completely fails to address either the cause or its consequences.

We're not going to invent hyperdrive, find dozens of new inhabitable planets, inhabit them, ruin them, finally realise what we already know about ruining the Earth with pollution and so on, and then inhabit some more planets and not ruin them, by the end of the century.

No, but you're well on the way to inventing the hyperbole drive it seems

...

It's the only propulsion system with the speed to chase the infinite improbability drive which some of the other members have equipped.

Why exactly are you so against the idea of sending people to other planets Peregrine? I get that it is expensive and robots would be much more cost effective but why bother sending anything into space if we aren't going to eventually leave Earth? Admittedly it does seem a lot more logical to send a bunch of robots over to the moon and start 3D printing stuff there before we think of going to Mars even if that isn't quite as glamorous but I suspect that will probably happen first as a test run anyway.

I am perfectly happy to let Musk burn through his own money trying to get to Mars if only for the new technology like reusable rockets, advanced space suits, and all manner of little things that we wouldn't have it is weren't for space exploration. He might be a very strange individual who doesn't know when to shut up but it is undeniable that he has a good vision for the world.

Stephen Hawking said we should spread humanity out as soon as possible to avoid an ELE and I am inclined to trust him as he was one smart cookie. I can think of no negative side effects of colonizing other planets in the grand scheme of things. There will be mishaps along the way for sure but when some idiot world leader launches all the nukes or we fail to spot a meteor racing towards us, it will be nice to know that humanity still has a backup plan.

 Vulcan wrote:

 Yodhrin wrote:
All that said, if we decide to allow corporations to go off and stripmine the solar system(and we bloody well shouldn't)...

Out of curiousity... why not? Would you rather they stripmine the earth, with all the ecological damage that entails? I would think it to be better to stripmine lifeless bodies rather than wreck the one body with a functioning ecosystem we can survive in...

So, okay. corporations are stripmining the planet we live on and are going to kill us all. That's what we're going with here. Why would we give them more to stripmine instead of stopping them from killing us all?






People can imagine the most fanciful leaps of technology to put people on Mars but can't imagine implementing already known systems to solve our current problems. Space discussion is just so myopic.

 Commander Cain wrote:

Stephen Hawking said we should spread humanity out as soon as possible to avoid an ELE and I am inclined to trust him as he was one smart cookie. I can think of no negative side effects of colonizing other planets in the grand scheme of things. There will be mishaps along the way for sure but when some idiot world leader launches all the nukes or we fail to spot a meteor racing towards us, it will be nice to know that humanity still has a backup plan.

"humanity" "the species" etc etc

Okay. Who is that? What organisations do they use, what beliefs do they have, what fundamental view of what a society is do they have? What is it that you think would be perpetuated?

 Peregrine wrote:

 An Actual Englishman wrote:
Which is I'm sure exactly what people said about concepts such as flight a few hundred years ago. Or going into space at all.

There will always be naysayers, there will always be optimists and there will always be people getting stuff done.

Only ignorant people said that about flight. Anyone with any sense saw that birds could fly, and human flight was just an engineering problem to solve. Any skepticism from informed experts was limited to the difficulty of finding an engine with a good enough power to weight ratio before 1900. See https://en.wikipedia.org/wiki/George_Cayley getting all of this figured out ~100 years before the first powered flight.

Contrast this with leaving the solar system and colonizing other planets, where the difficulties are well known to be effectively impossible and a direct result of basic laws of physics, no example of successful interstellar travel exists to prove that it can be done, and no plausible theory for how it could work is even under consideration. Short of a complete revolution in physics that overturns everything we know there is no clever solution that makes the time or energy requirements less of an obstacle. It is always going to be obscenely expensive and difficult to send anything outside the solar system, and there's no realistic scenario where we find a purpose for the trip that justifies the cost.

Interstellar travel is technically possible. It is just that it would take many Human lifetimes to get anywhere remotely interesting since traveling near or at the speed of light is technically impossible and traveling beyond the speed of light is physically impossible. So we'd be traveling at a speed far below the speed of light which means that entire generations of people would live and die aboard the spacecraft before it gets to a destination.
The challenges that need to be solved before interstellar travel is possible are still pretty big though. We'd need to be able to navigate extremely precisely over inconceivably large distances over great lengths of time. We'd need to be able to grow food in space. We'd need to be able to build a vessel that is large enough to for thousands if not tens of thousands of people to live on their entire life. We'd need to be able to overcome the negative effects of a lack of gravity on the human body etc.
So while it is technically possible, it is not something that is going to happen in the next few hundred years even if the current speed of technological progress holds out.

Also, Da Vinci had figured out you could build a machine capable of flight before the end of the Middle Ages. He just lacked anything that could give him enough power to pull it off (he did build a working hang glider though). Meanwhile, the Chinese had been building helicopter toys since at least 400 BC and knew that in theory they could be scaled up enough to carry a man, provided a force existed that was powerful enough to spin it and generate lift. They also achieved 'flight' by strapping people to giant kites. Flight had never been a mystery. People knew how it worked, they just had no way to make it work. Leaving the solar system is on an entirely different level (for example, unlike with flight we have no examples such as birds that we can study).


Automatically Appended Next Post:

Rosebuddy wrote:

 Commander Cain wrote:

Stephen Hawking said we should spread humanity out as soon as possible to avoid an ELE and I am inclined to trust him as he was one smart cookie. I can think of no negative side effects of colonizing other planets in the grand scheme of things. There will be mishaps along the way for sure but when some idiot world leader launches all the nukes or we fail to spot a meteor racing towards us, it will be nice to know that humanity still has a backup plan.

"humanity" "the species" etc etc

Okay. Who is that? What organisations do they use, what beliefs do they have, what fundamental view of what a society is do they have? What is it that you think would be perpetuated?

Hey! Don't try to trick people by asking rhetorical questions!

 Commander Cain wrote:
Why exactly are you so against the idea of sending people to other planets Peregrine? I get that it is expensive and robots would be much more cost effective but why bother sending anything into space if we aren't going to eventually leave Earth?

I think the point is that the HARD part is getting out of the gravity well. Once you've done that, why go down ANOTHER gravity well? Space is full of resources that can be used to build settlements in space. There's no advantage to settling a planet like Mars, which has a very thin atmosphere with no Ozone layer and no magnetic field to protect people on the surface.

If you're stuck underground or in a dome, you might as well be in a space station. Much of the desired science can be done via robots for a fraction of the cost of sending people - arguably we only sent people to the moon because the technology for robots just wasn't there yet.

A few dozen O'Neill cylinders (heck, just one good sized one) would protect humanity from ELE just fine. You can build them in Earth orbit and even move them (slowly) elsewhere in the Solar System if you need to.

There's a decent argument to settle the Moon for raw materials - it's close, has a small gravity well so throwing raw materials out will be easy (and we could build an orbital lunar elevator with current materials).

 John Prins wrote:

 Commander Cain wrote:
Why exactly are you so against the idea of sending people to other planets Peregrine? I get that it is expensive and robots would be much more cost effective but why bother sending anything into space if we aren't going to eventually leave Earth?

I think the point is that the HARD part is getting out of the gravity well. Once you've done that, why go down ANOTHER gravity well? Space is full of resources that can be used to build settlements in space. There's no advantage to settling a planet like Mars, which has a very thin atmosphere with no Ozone layer and no magnetic field to protect people on the surface.

If you're stuck underground or in a dome, you might as well be in a space station. Much of the desired science can be done via robots for a fraction of the cost of sending people - arguably we only sent people to the moon because the technology for robots just wasn't there yet.

A few dozen O'Neill cylinders (heck, just one good sized one) would protect humanity from ELE just fine. You can build them in Earth orbit and even move them (slowly) elsewhere in the Solar System if you need to.

There's a decent argument to settle the Moon for raw materials - it's close, has a small gravity well so throwing raw materials out will be easy (and we could build an orbital lunar elevator with current materials).

If we are at the point where we can feasibly build a fully functioning settlement in space then we are also at the point where we can reinforce Mars' magnetic field and atmosphere to the point that it becomes a pleasant place for humans to live.
Settlements in space are not a good idea. No one wants to live his life locked up in a space station with no gravity (not to mention the pretty bad ways in which such a life would affect the Human body). Living in space is only viable for the short term. I could see miners spending a year or so in a mining colony in the Asteroid belt, but after that they are going to want to return to Earth.
People don't want to live locked up in a small base or habitat. They want gravity, lots of space and fresh air and everything or else they are never going to be leaving Earth. The only way to get more habitable space outside of Earth is to settle other planets. And Mars is the only planet that we could turn into a place with breathable air, gravity and everything. It really is the only option for permanent habitation outside of Earth.

I mean sure, a point may come when we are able to build something like a giant O'Neill cylinder. But by the point where we can build what is basically an artificial planet like that, terraforming Mars will be a trivial endeavor in comparison. Not to mention that it will still be preferable since it provides immensely more space for an immensely lower cost and is also far less vulnerable.

Rosebuddy wrote:

 Vulcan wrote:

 Yodhrin wrote:
All that said, if we decide to allow corporations to go off and stripmine the solar system(and we bloody well shouldn't)...

Out of curiousity... why not? Would you rather they stripmine the earth, with all the ecological damage that entails? I would think it to be better to stripmine lifeless bodies rather than wreck the one body with a functioning ecosystem we can survive in...

So, okay. corporations are stripmining the planet we live on and are going to kill us all. That's what we're going with here. Why would we give them more to stripmine instead of stopping them from killing us all?






People can imagine the most fanciful leaps of technology to put people on Mars but can't imagine implementing already known systems to solve our current problems. Space discussion is just so myopic.

 Commander Cain wrote:

Stephen Hawking said we should spread humanity out as soon as possible to avoid an ELE and I am inclined to trust him as he was one smart cookie. I can think of no negative side effects of colonizing other planets in the grand scheme of things. There will be mishaps along the way for sure but when some idiot world leader launches all the nukes or we fail to spot a meteor racing towards us, it will be nice to know that humanity still has a backup plan.

"humanity" "the species" etc etc

Okay. Who is that? What organisations do they use, what beliefs do they have, what fundamental view of what a society is do they have? What is it that you think would be perpetuated?

I'm not saying this colony would be perfect, heck, left alone long enough I am sure Martian colonists would end up very different from humans in so many ways. They would probably end up with all new beliefs and systems of government (which isn't necessarily a bad thing ) simply due to the fact that they would be so far away. They would even by physically different to us if we go the genetic modification route but they would still be essentially human. Would you prefer a world ending event that simply wiped all major life on the planet with no one to remember the last 12000 years of progress and history we have made?

I just think it is a good idea to have a few backup plans. O'Neill cylinders after a bit of googling sound like a good idea as well and a moon base is definitely more viable at present but Mars still has the strongest potential for terraforming in the future.

The issue with a space station is that there is no room for expansion, population would reach a certain point and natural resources severely limited. It's not a direct comparison but if the people on the ISS were the last humans, they wouldn't last long at all. Without regular supplies or someone on the ground to help them get back they would be helpless. A super sci-fi vessel that could suck up space debris and maintain a fleet of shuttles could work but I think we are quite a way away from building the Enterprise!

Edit: Iron Captain also makes a good point, space at the moment is not the most friendly nor pleasant place to live...

 Commander Cain wrote:



The issue with a space station is that there is no room for expansion, population would reach a certain point and natural resources severely limited. .

Would they not simply build more space stations, or add chunks to it?

If it isn't one of the big cylinders, then you just launch up a module or two. The theory is you create a station that is self sufficient for food, water and air, then import any other raw materials from lunar bases or mined asteroids.

 Iron_Captain wrote:

If we are at the point where we can feasibly build a fully functioning settlement in space then we are also at the point where we can reinforce Mars' magnetic field and atmosphere to the point that it becomes a pleasant place for humans to live.

Well, not exactly. Giving Mars a magnetic shield is simple, but not easy. Basically you need a copper coil that can surround the planet, placed in orbit in front of the planet, to generate a magnetic field. It's a huge engineering project you'd probably need a space colony to build in the first place.

Wheel type space colonies are within our engineering capacity now and expandable (add more wheels). For anything space related, orbital manufacturing and off-world harvesting is going to be necessary. That should be the goal - once we have that, then the only limit is our engineering capacity.

 Gitzbitah wrote:

 Commander Cain wrote:



The issue with a space station is that there is no room for expansion, population would reach a certain point and natural resources severely limited. .

Would they not simply build more space stations, or add chunks to it?

If it isn't one of the big cylinders, then you just launch up a module or two. The theory is you create a station that is self sufficient for food, water and air, then import any other raw materials from lunar bases or mined asteroids.

Oh for sure I just meant that it would be no good if we no longer had a planet or moon base that could keep it supplied. The only reason we would need to build a habitable station of that size capable of housing a good amount of people is if we thought the planet was in some form of immediate danger and in that situation a different planet/moon would have better potential for rebuilding civilization.

 Kilkrazy wrote:
I agree. If you want to do mining in space, the asteroids are the place to go. If you can get to Mars you can get to the asteroids. Attach ion motors to a suitable rock and accelerate it slowly back to Earth orbit.

That said, there's actually plenty of easily get-at-able raw materials on Earth, so maybe we don't need to do mining in space, unless we want to manufature specialist materials in space and can't get the raw materials up from Earth easily enough.

With people's inevitable tendency to screw up I'd rather not have any substantial rocks being accelerated anywhere near earth just in case we end up triggering our own extinction event

 Commander Cain wrote:
Would you prefer a world ending event that simply wiped all major life on the planet with no one to remember the last 12000 years of progress and history we have made?

Then compile records of some kind and put them out there, somewhere. I don't believe that there is sufficient organisation on our current planet to actually launch serious space exploitation that wouldn't be some kind of get-rich-quick corporate scheme or some gadrillionaire's stupid vanity project.

 Commander Cain wrote:


Oh for sure I just meant that it would be no good if we no longer had a planet or moon base that could keep it supplied. The only reason we would need to build a habitable station of that size capable of housing a good amount of people is if we thought the planet was in some form of immediate danger and in that situation a different planet/moon would have better potential for rebuilding civilization.

Arguably a space station can be made to be self-sufficient, in that it can collect its own resources (by sending ships to asteroids) and build new stations and ships itself. You'd need those technologies to set up a self-sustaining Mars base anyways, and any permanent Mars settlement would probably need a permanent station in orbit for starters.

If you can get your spaceship up to near the speed of light, say at least 90%, then time dilation significantly reduces the subjective length of your voyage.

For example, travelling to Proxima Centauri at 90% of light speed would take about two and a half years subjective. This would still be a very long continuous voyage.

The problem of course is that you need to accelerate and decelerate, so you aren't travelling at 0.9c a lot of the time. The time dilation effect is more helpful over longer distances, though, because your acceleration and deceleration phases will be a smaller proportion of the total voyage.

All that being said, if you are travelling at 0.9c, collisions with interstellar particles and dust are going to be a serious problem.

Getting to 0.9c is science fiction, not reality.