Note: this is only for charged particles such as happen in solar flares, and only in space. Your personal shield against bullets and the like is still impossible, sadly.
Not one you could carry. One with an initial mass of 606,000 metric tons would have an initial power output of 160 petawatts, most of which was so high energy you'd have to worry about proton-antiproton creation on every atom those photons interact with, and it would still have a 3.5-year lifespan.
One of the benefits of using "human like" surrogates is the compatibility of hardware. Lets say its a spartan type design, if a human needed to be on the front lines for that space warfare to manage things then taking the hardware from a surrogate make all the other things in war easier (fabrication, supply, support, etc...).
You don't need 600 T, just a few tons of superconductor should be enough to stop most bullets. No need run any charge through them, just place them so that most of it is between you and the bullet.
The 6 order of magnitude resonant eddy current induction looks like the more interesting solution. I could see this being done with a giant beamforming array that would be more practical than a giant steady state magnet. It would be pretty cool to melt a supersonic projectile midflight with eddy currents.
In sci-fi, shields seem to basically evaporate bullets. A shield that melts bullets could be a very cool sci-fi visual; the ship would still need some conventional armor (you still have molten metal flying at you), but it would splat against the armor. Plus it would provide a nice visual for a fresh fleet vs the battle-splattered one that’s seen combat.
I think at that point you probably have to worry about the effect such a strong magnet will have on the brain and nervous system, so probably not the best fit for personal protection.
The bullets are the problem they are trying to use the shield to solve. If the shield also kills the user, that sort of renders the whole thing moot, right?
Not to agree with the actual idea that the magnet is necessarily dangerous, haven’t looked that up…
Not really. Bullet would just orient itself to minimize eddy currents. People would start using thin disc shape bullets that would slide through the magnetic field without much trouble after orienting themselves in the best direction.
"Just fire discs" well that's easier said than done, and there's probably a tons of reasons nobody uses discs. One of them is already that we have no experience building or using disc-shaped bullets, especially compared to the trove of experience for... bullet-shaped bullets. So that's not a solution as much as it's an indication that this defense mechanism wouldn't be perfect given an adversary with enough time and will. That being said, nothing is ever perfect, and "arms race" are named this way for this exact reason.
A strong magnetic field would affect all (eletrically conducting) bullets, they need not be ferromagnetic. This would work better on silver bullets than steel, actually (because of better conductivity).
Plasma could affect bullets and fragments (for example from mines). Just like current dynamic armor, which is just boxes with explosive material, and it's explosion deflect cumulative stream and fragments.
Imagine something like multiple-nozzle rocket engine.
Sure, existing proof of concept realizations are ugly, but with time they will become better.
Everything in space is about distance - want to stop an asteroid walloping the Earth? Nudge it when it is a few million [time or distance] unit away, and it will miss the earth. You could imagine a future spacecraft might have a leading arrowtip also with a field, many miles in front of it to deflect dust and so on.
Moving at significant proportions of c makes a very brief light show of pretty much any ablative solid, unfortunately.
It's worth doing the maths on, for instance, how much ice at 4K you would need to dissipate the energy released by running into a 5g pebble at 0.2c. It's... not a small volume.
Your comment made me try this out on wolfram alpha. Kinetic energy of 1 gram with velocity of 0.1 C is 452.78 gigajoules. Energy of the Hiroshima bomb is 6.3x10^13 joules. It would take 139.14 grams of matter at a velocity of 0.1 C to have the kinetic energy equivalent to the energy released by the bomb. So wow, yes, stopping even a small amount of stuff at those speeds is no joke.
The physics of kinetic weaponry is stupidly simple, and so kinetic defense is also stupidly simple: E = (mv^2)/2
Kinetic "energy shields" (as commonly depicted) are basically impossible, if not literally impossible. You're much better off either dodging or intercepting.
In physics of the impossible (in 2008, I know a lot of our opinions of the author have shifted) Michio Kaku makes a pretty good case that force fields are the least likely phenomenon to exist.
There’s just not a field that hangs out in space and forms a repulsive boundary to matter as its interaction, besides matter.
The EM field kinda, but no one means big magnets when they think of a practical force field (if so, “QED,” they already exist) :p
Nice! I couldn’t remember the details, but I was thinking of this too as the “maybe.”
I’m very skeptical of that story though. You’d think the strength of the electric field would have to be gigavolts/meter.
I just said gigavolts because of Doc Brown :p
I just know it would be more than a van degraff generator or a tesla coil. Lightning is in the 10k’s V/m.
I’m an electrical engineer (ok, ok, 3.5/4 of one. I had already graduated in CS, and quit early for a job).
I can’t imagine a static electric field with these properties.
The dielectric breakdown voltage of pretty much everything, especially air, would be relatively very small compared to that field, to generate a physical force at that distance.
Neodymium magnets can do that at millimeters apart, nothing really does at a few meters.
And why weren’t opposite or neutrally charged things sucked into it?
Sounds like a really sciency-sounding legend. Maybe there was a small effect and a story grew.
—
I just realized that the HN link is like 10 hours of everything I just said in the comments (but higher effort, I guess they went all 4-7 years, lol).
Haha, anyway. Add me to the skeptics. Life is usually boring :/
Gonna save this post for some arbitrary point in the future to pull out as a point against ‘impossible’. Might have to gift it to my descendants to make sure it’s available for long enough… /s
Doesn't sound very "viable" to me. From my reading, they are claiming that (a) magnetic shielding is impracticable for weight reasons; and (b) heavy electrostatic shielding can't currently achieve even half the protection required for a Mars mission.
TFA is unclear about what they mean by a "Mars mission". The amount of exposure an astronaut would face would depend on the duration of the mission, and a (say) two-day holiday on Mars doesn't make a lot of sense, if the one-way trip takes several months.
I think TFA's most-useful observation is a throwaway: "but you could probably get away with just picking old men for the job." Yes - just choose astronauts that aren't expected to live very long anyway. As a bonus, that makes it less important to figure out how to get them back.
I suspect my slip is probably showing: I'm very much a sceptic of long-distance manned space travel. It's definitely a job for robots.
> TFA is unclear about what they mean by a "Mars mission". The amount of exposure an astronaut would face would depend on the duration of the mission, and a (say) two-day holiday on Mars doesn't make a lot of sense, if the one-way trip takes several months.
Usually[0] such calculations are based on orbital windows, so approximately 15 months round trip time for a short stay and 34-month trip if you're trying to minimise fuel requirements. To get down to just 8 months would require on-orbit staging, which is basically putting supply caches in orbit, but even that's talking about 2 weeks on the ground.
But what matters is the time spent in space, not on the ground — once you're on the surface of Mars, things get a lot easier, as you've got a planet between you and the sun half the time, plenty of terrain to hide behind if you need to be out of line-of-sight, about 17g/cm^2 of atmosphere[1] between you and the sun even when it's at zenith, and the possibility of digging a hole to hide in.
[0] exception: someone is proposing a fancy new engine, perhaps a fusion torch drive or something.
> once you're on the surface of Mars, things get a lot easier
Yes, thanks for pointing that out to me. But TFA notes that (a) the Earth's atmosphere, and (b) the Earth's magnetic field, contribute nearly all of our shielding from both solar and cosmic radiation. Living in a cave on Mars might shield you from solar flares; but it will provide quite limited protection from gamma rays. Mars has a much weaker magnetic field than Earth (Wikipedia says there's no evidence of any magnetic field at all).
Indeed. Long term colonisation plans (if you can call them that at this point) generally come with "here's how to we make an artificial magnetosphere" — people do have solutions, though none of them are appropriate for just one mission on just one ship.
> I'm very much a sceptic of long-distance manned space travel. It's definitely a job for robots
Do you mean in the near term or forever? I agree that we shouldn't be expecting to send humans to Mars in the next few decades at least but I would find it absurd to say that we should never expect it to be viable.
> I would find it absurd to say that we should never expect it to be viable.
Well, never say never. Obviously, a manned trip to Mars is just a bunch of technical challenges, and technical challenges can be overcome. The planned Orion spaceship, powered by a stream of H-bombs, the size of a hotel, and built from ordinary steel, has long struck me as the most realistic prospect for long-distance space-travel (they said that if you want, you could bring an ordinary barber's chair or dentist's chair on board).
I can't see a Generation Ship working at all. Space travel requires personal commitment; my children can't be expected to have the same attitudes as me. Politics would destroy a Generation Ship. So I think the outer limit on space-travel is the distance you can travel before you die. That depends on velocity, but once you get into velocities comparable to c, the amounts of energy required are staggering. Getting protons moving at a fraction of c has required a huge international effort. Getting a human moving at those speeds seems simply infeasible.
So I conclude that it's unreasonable to plan on travel beyond the solar system.
Hm, that's fine, but it's taking the conversation in a different direction.
> Politics would destroy a Generation Ship.
Social constructions are also a form of technology and politics is also a technical challenge. I don't think generation ships are impossible on social grounds.
That's a remarkable claim, in view of the fact that political problems don't seem to be diminishing in the face of technical advances over 2,000 years. I don't think I've even heard of a technical formulation of political differences.
Of course, an 'iron fist' is a sort of technical solution to political problems; and the classical model of a ship has a captain who commands total obedience. But even ships with authoritarian captains have suffered mutinies; arguably, an authoritarian captain makes a mutiny more likely.
Are you suggesting that technology can solve political problems by psychological manipulation? If that's the deal, then I'll lead the mutiny.
> Are you suggesting that technology can solve political problems by psychological manipulation?
Not at all.
> That's a remarkable claim
I don't think so. I think it's self-evident.
You're not born knowing how to interact with others socially; it is learned. There is not one single technique for persuasion, but many rhetorical techniques. Therefore it follows that any given individual can learn to become more skillful and effective at social interaction, broadly. (I'm not specifically talking about manipulating or convincing others to do something they don't want.) It also follows that people can learn new social interaction techniques from each other and build on their skills by sharing. This is a form of technology; social structures and language are tools.
Social structures come in a range of complexities and types. Governments come in a range of complexities and types. Communication techniques, languages, ideas, etc. All can be built upon, adapted, and improved in effectiveness, as evidenced by the structures we've built upon the structures our ancestors have invented. For example, how do our legal codes compare to the Code of Hammurabi? Is it possible that Hammurabi could have spontaneously invented anything like the modern US penal system without building upon millennia of innovation?
And if we do agree that social interactions and structures can be improved upon, then the most remarkable claim would be to say that we must have already discovered all the techniques and their limits, and cannot learn new techniques for cooperation in new environments, without any evidence.
> You're not born knowing how to interact with others socially; it is learned.
I disagree. As I've grown older, it has startled me to observe the degree to which personality is innate, or inherited. I used to believe we were born tabula rasa, but since raising children and burying my parents, I see that my earlier opinions were absurd.
Well, obviously not many! They haven't learned to communicate, which is a bit fundamental to having social skills.
But they end up with personalities that were NOT trained into them. I don't know what is 'nature' and what is 'nurture', but I do know that kids arrive with their own personality, even if you can't yet discern it in the newborn infant.
Near-term, it's a job for robots. Very long term, the distinction between humans and robots is going to break down.
Although unlike GP, I don't consider a few months' hop over to Mars to be "long distance" space travel. I'm talking about visiting other stars: clearly a job for robots.
>I think TFA's most-useful observation is a throwaway: "but you could probably get away with just picking old men for the job." Yes - just choose astronauts that aren't expected to live very long anyway. As a bonus, that makes it less important to figure out how to get them back.
Why is this deemed as such a negative that people won't be coming back? Is it strictly fear of negative PR? I get that if an unscheduled rapid disassembly happens, that people get upset. However, if it is a part of the original plan that the first people will not be coming back, but instead become permanent resident aliens on Mars, then why is the negative PR being attached? People left their land to never return but settle and establish new places to live through out history, yet no negative PR was associated. Why now about Mars?
There’s something very alien about dying on an inhospitable, dead, cold world millions of miles away from all that humanity has ever known.
I find it hard to believe that we’d be able to find a sizable group of people who wanted this to be their fate and who were actually otherwise qualified for the mission.
Imagine the nightmare scenario of someone changing their mind partway through the mission. Talk about a disaster (PR and otherwise) that could be significant enough to chill the entire push for manned missions beyond the moon.
> I find it hard to believe that we’d be able to find a sizable group of people who wanted this
How do you think the Americas were settled by Europeans? These people decided that whatever their fate, it would be worth making the attempt. That's just the most recent, but history is clearly full of a group of people deciding that the horizon demanded to be investigated. Otherwise, we'd all just be massed together in what ever the current belief on where humans started is at the moment.
The call of the wild, the sense of adventure, exploration, or whatever you want to call it is part of human nature.
> Imagine the nightmare scenario of someone changing their mind partway through the mission
Yeah? And? So? You think people moving from Europe to the colonies didn't get cold feet? Hell, as times get hard, it's only natural to wonder WTF you made this decision. Those people will probably be culled from the herd so to speak. It's only a PR disaster because people like you sound like without the sense of adventure and too meek to do anything other than leave their house for work. Just because someone else is much more bold than you does not mean that you should prevent them from doing it because you might feel uncomfortable upon hearing about something.
I feel like your analogy conflates early explorers (who definitely intended to go home unless something went wrong) with early settlers (who did not). I feel like Mars is very much in the "explorer" phase more than the "early settlers" phase.
> How do you think the Americas were settled by Europeans?
These were families, who were setting out for the promise of a better life, to a world where they were promised fertile land and... a breathable atmosphere.
Do you understand how that might be completely incomparable to traveling to a dead world, where life will invariably be much worse, and there is no chance to bring your family or build a future with them?
There is no mystery, there is no unknown, there is no promise of riches or a better life, which is what explorers of the eras you're referring to were seeking.
> Yeah? And? So? You think people moving from Europe to the colonies didn't get cold feet? Hell, as times get hard, it's only natural to wonder WTF you made this decision. Those people will probably be culled from the herd so to speak.
You're being so glib, think a little longer. Did those colonists have twitter? Could a disaster be instantaneously broadcast around the world and cause a simultaneous shift in global perception and government policy? Think about the Challenger disaster leading to the end of the shuttle program. Could you conceive how a major disaster on such a ludicrously expensive undertaking as a Mars mission might result in cuts to the program and potentially all future plans for manned space travel beyond the moon?
>like you sound like without the sense of adventure and too meek to do anything other than leave their house for work. Just because someone else is much more bold than you does not mean that you should prevent them from doing it because you might feel uncomfortable upon hearing about something.
This is funny. Do you know the life I've lived? Are you confident that it's in alignment with your assumptions?
What gives you the idea that I do? Of course I don't know you, or you'd know that I did.
I phrased it in a way that indicates I don't know anything about you or how you think, but based on your writing it sounds like something else. That's all I said. I didn't say you were someone scared of adventure, but it reads like someone that is. As the saying goes, if it walks like a duck, quacks like a duck, it's probably a duck. Sometimes it's a swan though, so it's not a hard rule.
in those cases, people expected to live there, settle and have children, etc
Which seems very unrealistic for the first stage trip to Mars? you'd need several waves to even have enough material there to be livable for more than a year. No one moves to the south pole without a plan to go back, for instance.
> in those cases, people expected to live there, settle and have children, etc
exactly. These people are choosing to go to Mars without expecting to come back. If they die of old age or catastrophic failure doesn't matter. They willingly had no intent of coming back. So the cheeky comments about only send "old" to Mars is not totally out of line. Just remove the age constraint, and make it people willing to take a one way trip. There are people right now willing to do it.
It totally changes the agenda. If we can just plan on making long term remote isolated bases, then we just focus on that. But it takes the same amount of effort to survive on the surface for short stays that then require the extra effort of returning. So I'm saying we're wasting effort on the first stages including the return. Let the people willing to relocate do it, establish a foot hold so that the "weekenders" can come visit if that's something that is still felt as a need.
Well, sure. As long as they don't cause serious environmental and safety problems while they do it. But that's obviously a personal choice; it's absurd to expect the public finances to support the project. If they want to make money out of weekender tourists, then presumably they are making some kid of business plan; I'm fine with them losing all their money.
You’re missing that those people didn’t know what would happen and they had the hope of a better life at the end. Returning was always an option.
It doesn’t need to be rational. Humans are emotional beings and greatly affected about what they believe to be true.
Stranded on another planet is a guaranteed death sentence and people know that. They have no hope of survival to cling to.
You really can’t equate the two.
A better example would be a platoon of soldiers staying behind to delay the enemy so everyone else escape. They have deliberately made the decision to die for a cause.
I'm not missing the point at all. I think we're just willing talking past each other???
We've been sending robot explorers for decades. If we're sending humans, we should no longer be considering them explorers. They're settlers. Framing it any differently is just a serious limitation of what we're trying to do. Send up the equipment they need in advance. If the colonies fail (with all that entails), study it to see why and prep for the next attempt. It eliminates all of this hand wringing, and simplifies things to the point of becoming achievable
Its incredible to me that educated adults are taking long-distance manned space travel seriously. Its comically absurd and Dr. Strangelovian that people are floating "Send old people who will probably die soon" as a viable fix.
This is a job for robots and especially with new AI advances. Trying to fit the biology evolution created for Earth for non-Earth places is a classic square peg problem. I've always sort of mused that the 'gray alien' body is some sort of collective mythical idea of a space-engineered body. That is to say, if you want biological beings to casually work on other planets and moons, our Mark I primate bodies aren't good enough. Ethically, breeding 'space body children' should be a no-go for any civilization that values ethics and consent.
So that just leaves us robots, which not only makes scientific sense but ethical sense. Even the "old man" solution is unethical. We cannot know which one of these men might live to 100 if not bathed in radiation. Estimates on average age don't apply to the individual, so sending a 70 year old who will "die anyway in his 80s" is still very problematic. Fun fact, William Shatner is 92, so the famous Captain Kirk actor is one of those long lived individuals. Imagine sending him to Mars in 2004 at 72 because "he'll die soon anyway," but instead he's starting to look like someone who is going to live well into his mid or late 90s.
Its probably worth mentioning that when humanity does figure out a cheap and safe flight to places like Mars, Venus, moons of Jupiter, etc and figures out the engineering and bioengineering, we'll probably either be at our extinction event before then or AI will be at the level where we'd be just as much machine as human, or entirely replace by self-aware robots. So its a bit like those old film strips where they launch a manned cannon ball to the moon or an airship to go to Venus. The society, tech, and culture, etc of the time just wasn't far-seeing enough to understand the complexity of these issues and the changes needed to address them. We never danced around the moon's surface in Victorian gowns, used a sextant to navigate our spaceship, or brought a contingent of slaves to Mars. Modern thinkers are making similar mistakes as these naive old stories. Migration to the stars is just not going to be done in these bodies nor with this technology.
You’d find thousands of volunteers of any age for a manned mission to Mars, even if it were one way. I don’t think it’s unethical to let informed people risk their life
We'd find thousands of "volunteers" for blood sports, but we disallow them. Letting misguided people, the poor, the unwell, etc sign up for capitalist-backed suicide ventures is extremely unethical.
Once allowed, the corrupting influence of money would take over. People would be guilted into this by family for sponserships and such.
Not that long ago a woman received a huge forehead tattoo for an online casino as a PR stunt. They paid hew a few thousand for this stunt. She said she needed the money for her kids.
I don't think you're fully understanding how many desperate people out there would sign up for this or be forced into this against their will under the dishonest guise of "volunteering."
Look at the near revolt of the early space programs for example both Soviet and Western, with astronauts and engineers demanding safety measures and more personal control of the spacecraft after high profile "dog eat dog" philosophy failures that killed and injured many. We've already been through this. It doesn't work.
Lastly, a lot of engineers might walk away from the job for ethical concerns because they dont want to build suicide machines. Look at how MD's refuse to be part of state executions in the USA, thus leaving a cottage industry of a fairly incompetent execution industry. Your best people would walk away from SpaceX, Boeing, etc if tasked with making suicide machines for vulnerable people. People have ethics and not all subscribe to bottom-tier "dog eat dog" capitalism "volunteerism," but instead are educated to know what that means and how that's historically abused our most vulnerable.
Our most vulnerable populations wouldn't be of any interest as crew members of a spacecraft. They're the ones who wouldn't get to go at all.
The point of a crew wouldn't be to demonstrate human safety, but rather to do things automation can't currently do (e.g. improvise solutions based on a deep and broad background of general knowledge + specific training coupled with high basic intellect, in austere environments under great personal stress). People like that don't get their foreheads tattooed for money.
>Not that long ago a woman received a huge forehead tattoo for an online casino as a PR stunt. They paid hew a few thousand for this stunt. She said she needed the money for her kids.
Would her kids have been better off if she couldn't get that money?
We have for example test pilots who take high risks for their job without the slippery slope problems you describe so I don’t think that doing something similar for a Mars mission is impossible.
The question is acceptable to whom. There are pastimes that are risky such as rock climbing, Formula 1 racing, and many others. Would you ban those too? If not then you must accept that there are degrees of risk that are acceptable to some and not to others. Assuming that the decision is genuinely made without any kind of coercion why should society dictate what risks people can take?
As has been pointed out elsewhere on this topic the poor and ill educated won't be offered these opportunities anyway so that kind of implicit coercion does not apply.
> you must accept that there are degrees of risk that are acceptable to some and not to others
Someone who accepts the 'risk' of certain death on the mission doesn't seem to me to be the sort of person you want as your companion on a dangerous voyage. And if you're planning to found a colony, you want all sorts; not just nerds, scientists and technicians.
> Someone who accepts the 'risk' of certain death on the mission doesn't seem to me to be the sort of person you want as your companion on a dangerous voyage.
That is EXACTLY the person I want around, because I know they can be relied on even in dangerous situations. You, on the other hand, who thinks that someone who does not fear death would be a bad companion on such a mission, would likely piss himself in face of actual danger.
Someone who's afraid of death on a suicide mission is a danger to the mission and, thus, to myself. When you want to found a colony, you need strong men and smart men, best when each man covers both.
You definitely just want nerds, scientists, doctors and technicians, because they get the shit done.
> because I know they can be relied on even in dangerous situations
Why do you think such people are reliable?
For clarity, I'm not afraid to die. For exactly that reason, I think I'd be an unreliable companion on a dangerous mission. For my companion, I'd want someone who thought they had at at least as much to lose as me. If you want to head off to Mars with Rambo at the controls, that's up to you.
If you want to found a colony that is all scientists and technicians, because you don't think ordinary people "get things done", good luck with your colony. Pumping sewage, helping people in mental distress? Sure, leave it all to technicians; after all, we'll filter them for mentail susceptibility before they leave. We're good at finding nutters before they go nuts, aren't we? Well, no.
<Its incredible to me that educated adults are taking long-distance manned space travel seriously>
Comical and Strangelovian perhaps, but also the only hope for humankind. How many years until the expanding sun's corona envelops the earth? Assuming we make it that long without first destroying ourselves or meeting an unfriendly asteroid, you can bet that all of humanity will be behind the effort. So while it's not on this week's scrum board, it's definitely a high-priority TODO.
You make it sound as if humankind is doomed if we don't do it. But we're doomed anyway; no species on Earth has survived more than a coupla hundred thousand years without evolving into something else.
I think there's a desperate desire to live forever, behind some of the speculation about long-distance manned space-travel. Hey, guys, it's like this: you ain't gonna live forever. You won't be able to orbit Alpha Centauri, let alone colonize the galaxy.
100 years ago, we weren't at all sure that the Milky Way wasn't the same as the Universe. As we learn of faraway places, naturally we dream of visiting them; but now we know for sure that there are places we can see, that definitely can't be visited. We'll get over these dreams eventually, and maybe realize that we have to take due care of our home planet, and try to avoid killing one another in wars. Those are the great threats to 'hope', and the idea of survival through space-travel is a distraction for people who aren't prepared to face that fact.
> How many years until the expanding sun's corona envelops the earth?
So, so, so many years. We've gotten as far as we have in something like 200,000 years, with most of our technological advancement happening in the last...I don't know, let's be generous and call it 10,000.
It takes probably what, two hundred years for technology to become nearly unrecognizably advanced these days?
We have around 7 and a half billion years before the sun wipes us out. Trying to get people on Mars with current technology has its arguments, but that we'll run out of time if we put it off anymore isn't one of them.
Or, just make the vehicle being sent to Mars sufficiently large. Shielding mass needed goes as r^2; vehicle mass and volume as r^3. Just storing the cargo and propellant on the outside of the vehicle and the crew in the center should suffice for a sufficiently large vehicle.
Of course, cost goes up linearly with mass and thus cubed with `r`. Mars missions are expensive enough as it is without making the launch vehicle much bigger than required for the mission.
If going to Mars is worth doing, it's worth doing at scale. Considerations of "it's too expensive" mean one should work to make it cheaper, typically by reducing launch cost. It looks like we'll have launch costs of a < $10/lb to LEO before anyone seriously goes to Mars.
Just say no to flags-and-footprints (and SLS); say yes to large scale Mars activities.
> If going to Mars is worth doing, it's worth doing at scale
I don't think this is true.
If the main value is getting credit for putting the first human there, and doing a few experiments on soil samples or somesuch, then it definitely wouldn't be worth scaling things up, the same way its not worth doing missions to the deep sea, Antarctica or the Moon at scale...
> the main value is getting credit for putting the first human there, and doing a few experiments on soil samples or somesuch...
This is old thinking. I take the goal of self sustainable society on Mars very seriously. Will it happen in our lifetime? Probably not, but it is the goal we should be working towards.
I'm not being snarky (at least not intentionally). But you're saying a thing that is at the very least a superpower-level goal, if not a civilization-level goal, that is very clearly not a current priority, should. What's more you're saying it in a way as if it's completely self-evident that we should change our global priorities to focus on this without the slightest evidence supporting that assertion.
Well where do you see humanity in the future? In a realistic but also optimistic future? To me all of these futures involves us being a multiplanetary species, and starting to expand out into the cosmos more broadly. It's not only the only way we'll ever become a post-scarcity species, but also the only way we can secure our own survival as a species. There have been countless mass extinction events on Earth, and we're well overdue for another one, and it will come.
You're also probably grossly overestimating the cost. The SpaceX Starship program has been privately funded on a budget of ~$2 billion a year including all costs - research and development, construction, launches, etc. And once built it's expected to revolutionize space (again) sending launch costs to less than $10 million per flight, and price per pound to space into the low dollars! And once we can start transiting massive amounts of cargo to Mars, at a very affordable cost, colonization is very much within the domain of possibilities.
I would not contrast prices against NASA. NASA is largely used as a tool for pork and graft by Congress, that occasionally launches something. Their latest ship, the SLS [1], is literally reusing Space Shuttle era tech. I mean literally - the SLS is reusing refurbished Space Shuttle RS-25D engines, solid rocket boosters, and more. Managing to spend tens of billions of dollars over 13 years (and counting) to develop this is the special sort of talent you can only get from a company like Boeing.
So colonization will be costly, but it's nothing like a civilizational goal. It's just that our civilization only has governments mostly interested in fighting and dominating one another, just as has been the case for the entirety of human civilization. So we never really get to see what we could actually achieve if we tried. But what's finally changed is that these sort of grand achievements no longer require governments. Costs are plummeting at the same time private capital has skyrocketed. So the future looks brighter than ever!
You could reasonably define "post-scarcity" as "we've got more supply than we need".
In this regard, you can define scarcity and post-scarcity independently for every consumed resource.
We've been post-scarcity for oxygen since before we evolved; post-scarcity for water in most of the settled world; and now? Now we're post-scarcity for biros, photocopier paper, USB cables and wall-warts, and tchotchkes.
The only reason we're not post-scarcity for intellectual property is that we've created rules to induce artificial scarcity.
>We've been post-scarcity for oxygen since before we evolved
Have we? Our supply has been getting tainted with worrying levels of trace contaminants. If we had 100x as much atmosphere, maybe that wouldn't be an issue yet.
>post-scarcity for water in most of the settled world
"""Globally, 2 billion people (26% of the population) do not have safe drinking water and 3.6 billion (46%) lack access to safely managed sanitation,"""
As you quoted me, most of the settled world. Most. As in, more than 50%.
Personally I feel the main value of going to Mars is figuring out if it has or ever had life. That kind of search will benefit from scale. More tools to do more experiments, range farther from home base, maybe multiple landing teams. We could find ways to use an arbitrarily large payload. I guess that's not exactly what GP had in mind, though.
If you don't think it's a general property of things worth doing, what in particular about going to Mars means it's only worth doing at scale? It's a frankly bizarre claim that you've so far made totally unsupported.
Obviously I meant there are specific aspects of going to Mars that justify the statement, even if I didn't list them. I am not required to laboriously explain the justification behind any statement I make. We could discuss this further if you like. Your assumption that I had no such aspects and meant that as a universal rule is clearly not listening to me in good faith.
It's definitely not obvious if you spout off something that sounds like a platitude without elaboration that you actually only mean something very specific (let alone what specifically you mean), and while you're correct that you're not actually obligated to do so, you should provide some explanation if you have any interest in communicating effectively. Failing to do so is likely to lead to misunderstandings. But you've repeatedly missed opportunities to explain your position, even dodging explicit requests for clarification. That seems more like bad faith than just not reading your mind correctly.
I guess that's where politics comes into play. The reason NASA etc. are trying to push costs down isn't necessairily because it wouldn't be worth it if it was more expensive, it's just that projects that are cheaper have a higher chance of getting funded.
Also, the value of going to Mars is still highly speculative. Once we reach it with low-cost, smaller missions, it's going to be less speculative, and the risk/reward profile of sending huge spacecrafts will make them more viable.
Unless you source the mass from something that's already orbiting, like the moon.
Since we're mostly talking water, any moon water doesn't have to pay the rocket tax to launch from Earth surface.
And for a recurring trip, it'd make way more sense to keep a larger transit ship continually in either orbit or transit, with smaller barebones Earth/Mars cargo/crew transfer craft at either end.
It is hard to pencil out lunar materials being cheap, except maybe for use on the moon. If we're at the point where we are capable of in-situ utilization we probably have some kind of Starship-class rocket. The worst part of the "rocket tax" is not that you have to burn a lot of fuel or screw around with stages and refueling, but rather that you (1) throw the rocket away after one use or (2) it is a Great American Boondoggle like the Space Shuttle.
I do like the picture though of a lunar mass driver that sends up regolith, metal, or something like that to a catcher at, say, the L1 point.
A better option would be near-Earth asteroids. These require significantly less fuel to get to than the Moon and many are rich in ice. If you got really really lucky, you could even find one with an orbit similar to the Hohmann transfer path required to get to Mars and visit the asteroid en route. That way you don't even need to expend much fuel to transport the water to Mars; it's almost free.
For a return trip you could use Phobos and Deimos for material. They are also extremely easy to land on.
So? Do it in multiple phases just like we've done for the ISS. Isn't that one of the points of SpaceX building cheap/reusable rockets that can be launched quickly? Even Star Trek did this.
Which is why minimizing the mass portion budgeted toward shielding makes sense. If you're going to send 10 smaller ships or 1 large one, you better send the 1 large one.
FWIW, my idea of a perfectly reasonable piece of space infrastructure in the multi-planet era has a mass of around 10^11 kilograms. Fortunately, the infrastructure itself can bootstrap in a way that reduced the launch costs to, it is claimed, 9 kWh/kg: https://web.archive.org/web/20120306175303/http://www.paulbi...
The end is very funny. Mars trip costs 1200 mSv, NASA cap is 1000. Should we just send old men to Mars? Oops, they dropped the cap to 600, we need this tech now.
The NASA cap is a specific lifetime radiation dose; the Mars trip cost is an estimate of some kind, but they don't specify the duration of the mission. Is 1200 mSv the estimate for the outbound journey, or for both legs, or for both legs plus a 1-year stay on a Mars base?
I'm 68, and I've already had cancer; I probably match the "old man" criterion. But I won't be volunteering to travel through a hostile environment, to visit - a hostile environment. For pity's sake, use robots.
It's much more difficult and expensive to get a human encased in a robot to Mars, than to just get the robot there, without the human. The attitude of the human is largely irrelevant (although if you are going to send a human, it seems advisable to not send a suicidal nutter).
There’s a difference between a suicidal nutter and someone who wants to do it because they’re thrill seeking and to make the history books as the first person on mars.
Also, there’s a huge qualitative difference between a human on Mars and a robot on Mars in terms of what it means for humans back on Earth. It’s an achievement people will take pride in, can help unify people, & inspires the imagination of the next generation in a way that robots won’t.
Regulations will appear. There are already regulations about radiation exposure that will be immediately extended into space travel if no regulatory body acts quickly enough.
A short search gave me this number, apparently for the US:
> 20 mSv a year, averaged over defined periods of 5 years with no single year >50 mSv
Surely in such unusual circumstances any limits must be set as part of a cost benefit analysis from the point of view of the person concerned. One person might be rationally willing to risk higher exposure in the pursuit of knowledge.
I recently had a lung perfusion scan where I inhaled a saline vapor with technetium in it and I was the x-ray source for the imaging. When I got home I measured 43mSv/hr. I must be pretty close to the NASA limit. Too bad I'm not an astronaut though.
Would having a medical scan cause an astronaut to have a reduced usable lifetime?
I think the take away is that the progress has been surprisingly good and, if it continues, the next generation of designs after the ones we currently have might be viable.
What if we make the shielding once, put it in orbit and "borrow" it for each ride. Launching it from surface is expensive, between planets not so much. Even better, ship it in parts on the small reusable rockets that we already have. It's about time we start making stuff in space, welding a metal box seems like a good first project (also no shielding gas required)
Nice try, but unfortunately article have few factual mistakes and bias.
First, Earth shield is not just magnetic, but it is complex, magnetic + 100km of thin atmosphere, where most secondary particles just decay with time.
Calculations said, for comparable shield, need approx 6 meters of just water. Sure, it is lot of weight, so other calculations said, interstellar ship (or even martial ship) could use tanks with liquid hydrogen as shield, as they should be huge (for martian ship they should be thousands of metric tons, for interstellar, magnitudes more).
Second, very long text, but not said clear, that after cancellation of Shuttles, AMS-02 was modified, to use permanent magnet instead of superconductor.
Neat concepts, but these aren't going to fly any time soon. Quotes from the article:
"Take these solenoid designs. Your spaceship basically becomes an MRI tube."
"At the end of the day, though, we are still talking about using a roughly 40-ton shield to protect a module that weighs maybe 8 tons. It doesn’t add up. No space agency is currently considering putting a magnetic shield on a rocket because today we don’t have a good solution."
> Based on their simulations, Fry and Madzunkov built small-scale models of their electrostatic shields and tested them in a particle beam at Brookhaven National Laboratory with good results—they showed that the ASPP software was fairly accurate in its predictions. “We are at the stage where we need to start looking at building larger demonstrators. Stojan and I proposed putting a device on a lunar surface as a technology demonstration for the plasma mitigation method. Sometimes, you’ve just got to focus on applications that perhaps you don’t want to do first,” said Fry.
It is only a small scale model, but your comment really doesn't warrant such certainty about simulation only.
