Kind of depressing to realize we will never leave our own solar system ... more likely we are going to end ourselves as a species than taking that great leap.
It is just that humanity is not very good at consensus to even not suffocate in our own home.
Yes, the British Interplanetary Society did do a study on what a manned mission might be like, but they always seem to underestimate the biological problems of space flight.
If you wanted to colonise a planet around a nearby star it would be a truly staggering undertaking, even getting the fuel for an unmanned probe probably require H3 mining of Jupiter.
Dust is taken care by an ice shield in front of the craft.
Radiation is taken care by a water jacket. Radiation is only a real problem in the vicinity of the star. The atmosphere we have on Earth is only necessary to block radiation that comes from Sun either directly or through solar winds. The radiation from sources outside solar system might be high energy particles an photons but has very low flux.
The funny thing is, everybody focuses on technical issues where the biggest issue is most likely non technical and it is mostly about human health, physical response to lack of gravity and psychological to isolation.
The water jacket is intriguing, but doesn't it require a tonnage that's never been lifted into space yet? Had me thinking about a space elevator taking water up into space and also alleviating sea levels (to the point where much more water would be exported to something other than the shield).
It surely may be possible but involves risks and costs that no one is willing to take. Perhaps that balance of risk will change in the future.
Water would be a good candidate for both shield and jacket for the simple reason it is readily available in space in huge amounts and doesn't have to be lifted from Earth. What is necessary is a single remotely controlled ship that will go far enough from Sun to be able to capture and steer one of the watery asteroids. The further you go the slower the orbits the less energy you need to dramatically alter course of any astronomical body.
We don't even need to bring all that water to Earth. Instead, it might be cheaper to fly half-finished craft out, finish assembly by robotic means and then turn it into center of solar system. The craft could then gain velocity, use as many gravitational assists as possible on the way in and then back and pick up the crew before it leaves solar system for its journey.
This calculator says it would take 80 years when I approximate a solution where max velocity is .1c: https://www.omnicalculator.com/physics/space-travel?advanced...
.1c isn't fast enough to cause significant time dilation for the travelers so they end up spending nearly the same 80 years on the ship as well.
[1] https://www.airspacemag.com/daily-planet/ultimate-space-tele...
This is just a case go get a budget and build it.
I'm not betting on the current human race being capable of this, though-- in my opinion, we will need to more or less become a different species for anything like civilization as we know it to survive over the very long term. Otherwise we will inevitably keep wasting too much energy on emotionally driven, incredibly stupid and violent conflicts with each other.
The hard part is making them habitable for mammals which aren’t very hardy, need a lot of food, and reproduce slowly.
On the other hand several known designs mostly worked for humans to the point where using them would dramatically reduce the supplies needed for a long trip. But, none of them where operating on a zero G interstellar mission.
Biosphere 2 for example depended on sunlight which would be missing, but they provided sufficient calories across several months which means it was also generated enough oxygen assuming it had been setup properly to begin with. They had a huge range of other their issues, and you would need a vastly larger population and much higher efficiency for such a trip. But, from what amounted to a publicity stunt it was surprisingly close to a working solution.
https://en.wikipedia.org/wiki/BIOS-3 on the other hand was a far less ambitious project that was much closer to a practical design even if they imported food and the longest experiment was 180 days, it was actually using artificial lights.
PS: A more significant question is how to design hardware systems that could last for such a trip and what it would take to sustain things at the other side.
We are missing the technology to build anything in space, and to create small (dozens to hundreds of km of radius) ecosystems capable of sustaining people. We really do not have the technical means for space exploration.
The good news is that people are researching both, as improvements on them lead to profits here on Earth. So I do think we'll get there reasonably quickly.
This is mainly because no one tries to do it. If the biggest countries decided that they want to build it - I am sure humanity will solve all technical problems.
Isn't this "I'm sure" more wishful thinking than actual practical certainty though?
We made no contract with anyone that we can build anything we want as a species...
That's part wishful thinking, part hand-waving. There are tons of practical limitations that prevents us from leaving the solar system based on the nature of space and physical laws.
At best, we could get some "generational ships" out going to nowhere knows where exactly (it's not like we have some habitable planet to even aim to in mind, and the various "atmosphere-making" schemes are pie in the sky and require tens or hundreds of years, plus tons of resources in that "generational ship"), but even that is less likely than regression or extinction here...
On our own timescale terms we have a rare tendency to group together for intra species battles, and a unique tendency to do that with groups numbering millions.
We have an evolutionarily unprecedented and unmatched phenomenon, advanced intelligence, which we employ in scaling the destruction in those battles, to the point we now have the ability to cause catastrophic, possibly existential damage to our species, at least as a civilisation wherein this discussion makes sense; let alone the collateral damage to our environment and co-habitees.
That's just the war stuff.
The peaceful things we do are too depressing to mention.
For example: https://en.wikipedia.org/wiki/List_of_nuclear_close_calls
Assign a non-zero probability that it'll actually go wrong, then extrapolate 10.000 years into the future.
The odds aren't necessarily in our favour. And that's just one of many risks out there, over the course of a blink of an eye in the history of the universe/galaxy/earth/humanity.
We did not have the ability to end ourselves in the past.
How would dolphins or monkeys end themselves even if they wanted to, short of mass suicide?
We have had this capability only in the last 100 years or so in mainly 2 ways:
* atomic armageddon
* destroying our habitat
We managed to hold on for that first one for the last 50 years but we are busily and productively working on that second point, so I'm not quite sure where your optimism comes from.
True for our generation, but then think of how far we have come just in the past 100 years (Wright Brothers to Musk). The next advances will kinda be logarithmic.
The next century's advances are going to be things like "rediscover calculus" and "build a working steam engine."
Those fuels are running out, and we have to stop using them in any case before we kill the planet.
To my view the C19-20th has been a unique period of growth. We're going to need to be much more resource and energy conservative until {and even when} we develop new technologies (fusion? some sort of zero-point energy harvesting??).
It seems renewables might be able to satisfy our current energy demands, as long as we don't do something like thinking we can continue along the curve we've been going on, particular wrt population growth, but also wrt our expectation of a bottomless pit of all elements.
Our next revolution needs to be extreme longevity of goods/tools/appliances and full reuse/recycling. IMO that's incompatible with Capitalism, we need producers who are invested in _not_ selling more products than are needed and investors who want to achieve goals beyond extracting liquifiable value from our societal systems.
Even going back to feudalism I fear we've fostered into power the sorts of people who will never choose the trajectories we need but will always go for personal wealth. It might already be too late to correct that.