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[smjjames]

It's not just ratings. It's the entire life support system and attendant shielding and heat load. Not only is there no reason to build and test these for automated spacecraft, there's also zero incentive to build the capability to carry them -- of which the added mass is arguably the simplest component to handle of many -- into the hardware launching them.

In a sense, the cost of spaceflight is so high because it's presently necessary that every flight be entirely self-supporting; we need rockets that can reach space from a stationary pad and carry everything required along with them because it's not profitable to leave anything up there for their use. That need not be true of robotic spaceflight for scientific and industrial purposes, but the things rich idiots need to take joyrides and publicity stunts are different, and therefore become economical to supply on an ongoing basis and attendant lower per-flight cost only if there are enough rich idiots to make them so. Air travel at least had the benefit of being uniquely useful for shipping to people in otherwise inaccessible locations and needing a human in every plane and therefore every plane capable of carrying humans. Space travel has neither those uses nor those restrictions.

Unless you're saying we're never going to send people into space again and live entirely planetbound, with theoretical robots doing theoretically everything we might ever want to do, we're going to need to keep developing rockets that can transport people into orbit. I doubt spaceflight will ever be entirely human-free.

Both SpaceX and NASA have indicated plans to land people on mars and colonise, and SpaceX already have sharply driven down launch costs. They're only going to get lower.

You could say that it's a bootstrapping problem, making it work and doing it for the first time is the hardest and steepest part of space colonization. It's not like we don't know what to do, it's just that difficulty slope is a difficult one, and once it gets done, the slope gets easier (or maybe it just seems like it gets easier because you're following in the footsteps of others).

What trekkin is getting at:

There is nothing on the moon that is terrifically valuable that cannot be much less expensively obtained, processed, and used right here on earth. As such, there is no real ECONOMIC reason to go to the moon (other than its strategic locality for other space operations).

Because of that, WHY would people relocate their families, WHY would businesses go there, et al.


You have to think in those terms, not star-struck optimism.

Right NOW, yes, it's not very economically viable, but as technology and techniques improve, it can become viable.

[Trekkin]

What trekkin is getting at:

Don't put words in my mouth, wierd.

What I'm actually getting at is this: unlike every other form of transportation developed to date, including air travel, there's no reason we absolutely have to include humans on every single spacecraft from the get-go. Therefore, unlike air travel, not everything needs to be man-rated or survivable, and much like air travel (see drones, for example) there's quite a lot you can do if you don't need to haul people around and keep them safe: in broad terms, you can go smaller, faster (or with more extreme acceleration, for the knee-jerk pedants), hotter, and lighter. It is therefore inaccurate to assume that space travel will follow some hazy analogy to air travel and become a cheaper form of passenger transport as it becomes more useful, because spacecraft don't need to be nearly as close to being able to carry passengers to be useful.

I'm not saying we're never going to build cheaper ways of getting people into space, but I am saying that we're not going to build them out of repurposed probe launchers.

[Telgin]

I've seen a number of sources say that mining helium-3 on the moon would be profitable and worth exporting back to Earth, but I'm pretty skeptical.  It definitely doesn't seem like the sort of thing that would make such an endeavor really economically viable, anyway, unless I'm way underestimating how much helium-3 there is on the moon.  Maybe lunar installations would make sense as processing facilities or stepping stones to asteroid mining, but that also needs us to develop the tech to mine asteroids first.

Space elevator/launch loop would take care of it.

Too bad those are beyond our capabilities right now, IIRC both require material qualities we don't have.

I know I'm getting a little off topic here, but I'm not convinced a space elevator would really help either.  A launch loop, maybe, since I'm not really familiar with that.  Anyway, a space elevator's big issues, even if we could build one, are capacity and speed.  Most design proposals I've seen have climbers that take days to get to space.  So, if it takes, say 3 days to climb, that's about 120 trips per year.  You now need to send about 650,000 people per trip to break even, divided by however many elevators and climbers you have.  It's going to take a ridiculous capacity to reach a break even point.

All speculative numbers, of course, but I'm just trying to show the scale of the problem.

[wierd]

That is one of the things you were saying, yes--  But you also said this:

Or don't, because quite unlike air travel there's nowhere to go. Everything it is profitable to do in space at scales that actually drive costs down can be done more cheaply, safely, and most importantly less massively by robots.

and this

It's not just ratings. It's the entire life support system and attendant shielding and heat load. Not only is there no reason to build and test these for automated spacecraft, there's also zero incentive to build the capability to carry them -- of which the added mass is arguably the simplest component to handle of many -- into the hardware launching them.

In a sense, the cost of spaceflight is so high because it's presently necessary that every flight be entirely self-supporting; we need rockets that can reach space from a stationary pad and carry everything required along with them because it's not profitable to leave anything up there for their use. That need not be true of robotic spaceflight for scientific and industrial purposes, but the things rich idiots need to take joyrides and publicity stunts are different, and therefore become economical to supply on an ongoing basis and attendant lower per-flight cost only if there are enough rich idiots to make them so. Air travel at least had the benefit of being uniquely useful for shipping to people in otherwise inaccessible locations and needing a human in every plane and therefore every plane capable of carrying humans. Space travel has neither those uses nor those restrictions.

Those are 'connected' to your stated point, but only tangentially.   

Unlike "setting up operations in the Hudson Bay", where there are native resources of considerable value to gather (furs, unique forms of meat and other luxury commodities that can be resold at a high price) the moon has no such prospects. There is no economic reason to outlay the expenses needed to send humans up there. You are correct that robots can do basically anything humans would be doing up there, as it relates to exploration, science, and even some light manufacturing to support those, and that the facilities needed for robots are not at all the kind needed for humans.  To get the kind needed by humans, you need a reason for humans to be there-- to wit--

Why I pointed out the precedent of the victorian mansion.   This was before automation in a lot of tasks, like laundry or kitchen, or cleaning even.  The desire to appear opulent and stately is historically big enough to cause the wealthy to pay to feed, clothe, and house literally hundreds of people-- JUST to maintain their opulent homes.

Right now, most of the very wealthy have ocean front luxury properties of one form or another, (though some do live in deserts already), which will either become underwater, or be otherwise rendered a tax writeoff in the coming decades if the trainwreck of human produced CO2 does not get prevented and cleaned up.

There is only so much real-estate that would be aesthetically pleasing/safe in that future, and so I can easily see how the moon would be attractive. (very hard for the plebians to send pitchforks and torches without rockets, no?)

Sure, it would mean having to resort to the victorian mansion model, with armies of support crew, but again-- it's been done before.

[wierd]

I've seen a number of sources say that mining helium-3 on the moon would be profitable and worth exporting back to Earth, but I'm pretty skeptical.  It definitely doesn't seem like the sort of thing that would make such an endeavor really economically viable, anyway, unless I'm way underestimating how much helium-3 there is on the moon.  Maybe lunar installations would make sense as processing facilities or stepping stones to asteroid mining, but that also needs us to develop the tech to mine asteroids first.

Space elevator/launch loop would take care of it.

Too bad those are beyond our capabilities right now, IIRC both require material qualities we don't have.

I know I'm getting a little off topic here, but I'm not convinced a space elevator would really help either.  A launch loop, maybe, since I'm not really familiar with that.  Anyway, a space elevator's big issues, even if we could build one, are capacity and speed.  Most design proposals I've seen have climbers that take days to get to space.  So, if it takes, say 3 days to climb, that's about 120 trips per year.  You now need to send about 650,000 people per trip to break even, divided by however many elevators and climbers you have.  It's going to take a ridiculous capacity to reach a break even point.

All speculative numbers, of course, but I'm just trying to show the scale of the problem.

Instead of a single carriage going up the elevator, instead, imagine a "circular" train track, spiraling up the thing.   At the top and the bottom the track goes half-way around the circumference of the elevator, which is where pick-ups and dropoffs happen.  The train is continuous operation at a slow but reliable pace.  You could mass-transit stuff into and out or orbit that way.

[smjjames]

I've seen a number of sources say that mining helium-3 on the moon would be profitable and worth exporting back to Earth, but I'm pretty skeptical.  It definitely doesn't seem like the sort of thing that would make such an endeavor really economically viable, anyway, unless I'm way underestimating how much helium-3 there is on the moon.  Maybe lunar installations would make sense as processing facilities or stepping stones to asteroid mining, but that also needs us to develop the tech to mine asteroids first.

That's kind of the crux of the problem, we haven't yet developed technologies that can do it, but we kind of have to go there in order to field test the technologies. Those initial steps wouldn't need humans on site, but given that we haven't yet invented self repairing machines (yes, I know there are self repairing materials around even if it's only in the lab, but that won't help if something REALLY goes wrong), so, we're going to want people there at this technological stage.

Space elevator/launch loop would take care of it.

Too bad those are beyond our capabilities right now, IIRC both require material qualities we don't have.

I know I'm getting a little off topic here, but I'm not convinced a space elevator would really help either.  A launch loop, maybe, since I'm not really familiar with that.  Anyway, a space elevator's big issues, even if we could build one, are capacity and speed.  Most design proposals I've seen have climbers that take days to get to space.  So, if it takes, say 3 days to climb, that's about 120 trips per year.  You now need to send about 650,000 people per trip to break even, divided by however many elevators and climbers you have.  It's going to take a ridiculous capacity to reach a break even point.

All speculative numbers, of course, but I'm just trying to show the scale of the problem.

I wasn't trying to imply earlier that using space travel to relieve population pressure would be viable, just saying that there are more reasons than simply 'it's overcrowded in here!'. Plus describing a type of population pressure, but I think that was actually an economic pressure (or magnet rather) and not a population one.

@wierd: I was actually thinking of the river when I said 'on the Hudson', but the bay makes more sense as far as 'trading outpost'. And I wasn't talking about resources, just that it's a heck of a lot easier to set up an outpost on Earth than it is on the Moon because there are loads of things you'd have to worry or think about you otherwise wouldn't on Earth.

[RadtheCad]

It's not just ratings. It's the entire life support system and attendant shielding and heat load. Not only is there no reason to build and test these for automated spacecraft, there's also zero incentive to build the capability to carry them -- of which the added mass is arguably the simplest component to handle of many -- into the hardware launching them.

In a sense, the cost of spaceflight is so high because it's presently necessary that every flight be entirely self-supporting; we need rockets that can reach space from a stationary pad and carry everything required along with them because it's not profitable to leave anything up there for their use. That need not be true of robotic spaceflight for scientific and industrial purposes, but the things rich idiots need to take joyrides and publicity stunts are different, and therefore become economical to supply on an ongoing basis and attendant lower per-flight cost only if there are enough rich idiots to make them so. Air travel at least had the benefit of being uniquely useful for shipping to people in otherwise inaccessible locations and needing a human in every plane and therefore every plane capable of carrying humans. Space travel has neither those uses nor those restrictions.

The life support and shielding is just part of the payload.  It's not really added mass, just mass that was always part of the equation to begin with. 
I don't really disagree.  Whether rockets tend towards heavy lift will have some influence, as well as how low the launch cost gets.  That'll determine how rich the rich idiots have to be.  Do you have to be a billionaire to go to space?  Or a millionaire?

On a side note, how do human brains rate compared to computers, as spaceship cores?  Ignoring the psychological and ethical problems, brains are very efficient computers that last for decades.  How much mass and power would life support and shielding would a brain need per unit of computation compared to a computer?  I know the power efficiency is many orders of magnitude better, but how about mass efficiency?
I guess this leads into a more general point about organic computers vs. silicon.

[wierd]

Oh no.  Life support, and the need for return fuel, amongst other considerations, makes robot missions and human missions VASTLY different fish.

A robot can handle G forces from turns, acceleration burns, etc--- that would turn a human into pink goo.  It also does not need to be returned to mission control, or otherwise be returned to a staffed facility when the mission is complete, like a human vehicle does.   It can just sail off into interstellar space and never be seen again, and nobody would care.

The cost differences between the two are astounding as a result.  You need only a tiny fraction of the fuel to reach a target location and do some science, for instance. Don't need near the level of power consumption, are less likely to spread research contaminating microbiota all over the solar system, et al.


When it comes to research, robots have humans beat when it comes to data collection.  They are already completely objective in what they report, as they are incapable of intentional bias (there might be bias due to defect, but that's another matter), they can be 100% germ free, they dont need air, food, water, or a place to sleep or shit.  They can theoretically operate non-stop, the infrastructure they need is significantly lighter weight.....  I think you get the idea.

The difference between a human mission and a robot mission, in terms of cost, is comparable to a high end ferrari vs a moped.  Night and day difference.  Also, like the ferrari and the moped-- they are vastly different vehicles, for different purposes.

[Madman198237]

I feel it might be important to point out that wierd has not mentioned the massive advantages humans bring: We are adaptable, and can adapt other things. We can do much more than a robot ever could, given the same tools as the robot. Also, if we see an interesting rock, for example, a human can pick up and then use some scientific instruments on said rock, whereas unless the robot was specifically designed to be able to pick up that rock, it might be unable to do anything except send back some pictures, which is useful but far less useful than the human being. In order to bring that incredibly advanced capability to some place out there in space, though, you do need an order of magnitude or so's additional transport capability.

[wierd]

Here is how I see it, as regards science.

I can see the need for an orbital science station, staffed with humans of various career types. If we are talking a mars mission, I could see a logistics station on phobos or deimos. This solves a number of issues with long-term research.

1) Com delay is reduced from minutes to a fraction of a second.
2) With other satellites in orbit, there is no com blackout
3) There's local raw material to construct additional science instrumentation to send to the planet below
4) very weak gravity well makes launch of instrumentation inexpensive; also facilitates crew rotation (transport vessel does not have to do atmospheric landing and takeoff)
5) physical isolation of humans and their disgusting germs from the planetary environment being studied helps assure that the thing being studied does not get contaminated, and thus ruin future research.

Don't misunderstand me.  There is a need for human spaceflight. Just raw data gathering science missions are not really one of them, outside of logistical support. (like laid out above.)

A small research station on phobos is not geared to become a transport hub, however.  It would be geared to have minimal crew, would expect frequent supply missions, and would have only minimal manufacturing or docking capacity.  Its reason to exist is to move mission control closer to the science, so that you dont spend 90% of your time waiting for the probe to respond to your orders.

[smjjames]

Once colonization becomes a thing, theres going to be people who decide to do it just for the adventure or just find their own reason to go and put a stake in alien ground. But still, it's that whole 'first step' issue that has to be surmounted and there probably won't be a permanent population for a long while once a base starts getting set up on the Moon or wherever as we as a species begin learning how to colonize other worlds.

The whole development of space stations is pretty analogous, there aren't permanent residents yet (primarily due to radiation exposure issues), but people have been staying in the space stations for longer and longer periods of time.

[RadtheCad]

Oh no.  Life support, and the need for return fuel, amongst other considerations, makes robot missions and human missions VASTLY different fish.

A robot can handle G forces from turns, acceleration burns, etc--- that would turn a human into pink goo[..]

I'm not sure if you're replying to me...  please note that I said a human brain, not a human.  And ignoring ethical concerns- given you've cut out someone's brain and stuck it in a probe.  How much hardware do you actually need to recycle waste into sugars and vitamins and hormones and...
Well, probably quite some.  But how much will it mass?

Your g-forces point is probably a killer (is the brain the weak link in the human body when it comes to G-forces?  Does it need to be?) and besides, a normal human mind isn't what you'd want for something like this-  you'd want some mind that can pay attention when needed, and otherwise sleep for weeks on end.
You'd presumably equip it with a normal computer as well, anyway- it's probably just there for quick and flexible response.  It?  They?

But this is getting into way-out-there technology territory.  More realistic than full humans in full human bodies, though.

[Reelya]

Instead of a single carriage going up the elevator, instead, imagine a "circular" train track, spiraling up the thing.   At the top and the bottom the track goes half-way around the circumference of the elevator, which is where pick-ups and dropoffs happen.  The train is continuous operation at a slow but reliable pace.  You could mass-transit stuff into and out or orbit that way.

https://en.wikipedia.org/wiki/Lunar_space_elevator

The Lunar Space Elevator will come first. It's a tether which is feasible with known current materials, much cheaper than an Earth-based elevator, and the end of it is dangling in High Earth Orbit so you only really need to nudge things off the end of them to get them heading towards Earth. Maybe and Earth elevator will be buildable one day, but this thing is far more reasonable and we shouldn't even think about an Earth one before building a moon one.

Maybe if we just build a long enough moon-elevator it will be dangling into Earth's atomsphere so you only need airborne shuttles to dock with it? The advantage would be that the position rotates around the Earth on a monthly basis so it's cheaply accessible to many locations.

[Trekkin]

Oh no.  Life support, and the need for return fuel, amongst other considerations, makes robot missions and human missions VASTLY different fish.

A robot can handle G forces from turns, acceleration burns, etc--- that would turn a human into pink goo[..]

I'm not sure if you're replying to me...  please note that I said a human brain, not a human.  And ignoring ethical concerns- given you've cut out someone's brain and stuck it in a probe.  How much hardware do you actually need to recycle waste into sugars and vitamins and hormones and...
Well, probably quite some.  But how much will it mass?

Given how much of our metabolism the brain uses, the combined mass of the support structure to keep it alive for over multiple years (since anything that wouldn't take that long probably isn't going far enough away for the light lag of remote control to be a problem) and the interfaces for getting data into it and commands out of it, combined with spares for all of that, probably isn't going to weigh meaningfully less than a human, particularly given the added mass of repair armatures. The life-support systems on most seriously designed near/midfuture spacecraft are simultaneously among the more complex and more reparable structures, but that latter part doesn't help if the life it's supporting doesn't have hands.

[smjjames]

Sudden g-forces tend to be more of a problem for the brain than gradual increasing g-forces.

As for total g-forces, there is a point (5gs for most people and 9gs for pilots wearing special suits) where you black out because the blood is being forced into your legs, and lethal g-forces for the brain would be at the same time other organs start getting screwed. The human body can actually handle quite a bit of g-forces, so, if they're in an acceleration couch (in various forms in sci-fi), they'd be fine with some acceleration, but if you want to walk around or otherwise be functional, the threshold isn't very much.