[ExI] simulation as an improvement over reality
sjatkins at mac.com
Thu Dec 30 23:12:11 UTC 2010
On Dec 30, 2010, at 5:41 AM, Eugen Leitl wrote:
> On Thu, Dec 30, 2010 at 03:46:41AM -0800, Samantha Atkins wrote:
>> Sure. Someday. But not first to attempt to gain cheap
>> and plentiful enough energy to keep our technological
> I mentioned the threshold to SPS to be PV contribution to total
> at high multiple 10% across industrialized nations. Right now
> Germany barely managed 2%, peaking at 20% in rare days.
As you know, PV is not cost competitive generally speaking with other means of generating electricity today. Until it is it will not be rational to raise the percentage of all power that comes from solar very high. Remember that the wealth (in the sense of quality of life, options and ability to do things) of any population is directly dependent on per capital energy availability which in turn is dependent on the cost of that energy.
> I doubt the exponential trend can keep up, since there are
> no scaling laws to help you. Even if you can ink up km^2,
> you still have to put them up, wire them up to the grid
> and/or buffer the power.
>> momentum up. We need that long before we are capable
>> of deploying SPS systems in GEO and/or on the moon.
> I agree. How quickly the need arises depends on ability
> to transport energy over long distances (high-voltage
> DC, hydrogen pipeline) or buffer them. Supercaps might
> make a difference, but you'll probably need large-scale
> cheap electrochemical energy sources. Availability of
> either in time frame required is not guaranteed.
Miniature nuclear burry and forget plants help some too. The demand for energy is increasing and Peak Oil is real. Unless we want much hotter energy wars and massive economic consequences than we now experience we must replace oil and its derivatives especially as the primary means of motive (transportation) power. Make the transportation grid more expensive and a lot of our civilization and trade patterns begin to fall apart.
>>>> The reason is that we don't have the robotics
>>> I don't think it's a hard problem these days.
>>> There have been a number of past bootstrap
>>> plans, see http://www.molecularassembler.com/KSRM.htm
>> Lets see. 4000 - 20000 metric tons of panels,
>> concentrators, antennae and so on for an SPS.
> In general you would want to use um-thin layers of
> photosynthetic material (probably also doubling
> as solar sais), and with phased-array microwave
> radiators (capable of realtime beamforming to track
> groundside rectenna arrays with smooth handover)
> integrated into the bottom of same array.
You can't us the thin and lightest options if they need to be rad hard for the GEO environment.
> The difficulty would be in fabricating these and
> assembling them into packages which can be launched
> via linear motor (with some rocket assist), and
> can be aerobraked.
>From earth or moon? Linear motor from earth would likely be too heavy acceleration for such structures.
> You would be probably easier to fabricate metal
> and semiconductor-grade silicon ingots and insert
> them into suitable Earth orbits, to be processed
OK. Much more infrastructure required to be in space then, including partial fab plants it sounds like.
>> Assuming you can get it out of the gravity well
> Out of the lunar gravity well. Dropping them
> into the Earth well is much easier, with
Which presumes significant infrastructure and advanced manufacturing on the moon which is at least a generation away currently. What is your favorite proposal for getting massive amounts of gear to the moon? Ocean based nuclear gun, Orion?
>> (or mine and manufacture in near earth space)
> That might make sense, since making very large
> extremely thin panels might require microgravity.
>> then there is a huge need for workers / devices
> Teleoperation. Even easier in LEO.
SPS will be in GEO, not LEO. Mining earth asteroids is deep space work. Lower delta V to exploit them than trips to/from the moon but longer travel times for most of them.
>> of some kind to assemble and maintain all that
>> lot in GEO or on the moon. We don't have
> GEO is too far.
GEO is essential for SBSP beamed to earth.
>> anywhere near that many astronauts and do not field
> Monkeys will stay on the ground. Teleoperation
> platform can be handed over 24/7/365 for
> groundside crews.
Again, not fast enough for space operations we do today. And we don't have the teleop tools to operate in that environment either. If we did then space walks to fix various gear or pulling along side with a manned shuttle and robotic arm would be unnecessary.
>> them for space walks in GEO on an extended basis
>> in any case (much harsher radiation danger than LEO).
>> So having humans do it is not going to cut it, not
>> in the next decade or two at least.
> I think space monkeys is going to become an even
> rarer species with each coming decade.
Yeah, IFF we develop the autonomous and self propelled (for some varieties) space robotics.
>>>> or huge (and expendable) human astronaut population
>>> Space suits don't really work, so why not use
>>> teleoperation? Even NASA has wisened up meanwhile
>> You can't beyond a certain range for anything requiring
>> relatively continuous adjustments. But you can run more
> Yes, which is why I keep harping about the next rock
> from here. 2.5 pingpong times are still doable with
> trained operators, but they also give you incentives
> to install local reflexes into the teleoperated system,
> turning the human operator increasingly into a planner,
> and the remote system as a (pretty dumb) executor of
> a plan.
>> nearly autonomous bots at greater distance. But we don't
>> have hardly any construction bots fully proven out in space.
>> Some of the attempts have had serious problems such as
>> joints that freeze up if the power ever drops.
> The problems with UHV are pretty much fixed (though of
> course you have to design for that). Working in abrasive
> dust environments, with electrostatic charging, and also
> in cryogenic, very cold environments (<90 K in polar
> lunar craters) will pose some challenges.
>>> And of course there's not much point in teleoperating
>>> the robot from nearby pressurized vessel, if you could
>>> leave the human at home. The Moon is close enough
>>> for teleoperation,
>> Not for a lot of teleoperated processes.
> There are not a lot of teleoperated processes
> on this planet. There are very few humans hurtling
> through the thermosphere, with very little time
> spent outside. They're still using robotics arms
> and you'll notice that the R2 will become a permanent
> resident on ISS.
Yes and they accomplish very very little. Replacing a few parts becomes a newsworthy event. Sad, isn't it? Robonaut is flawed. Too great an attempt to use the same human tools when having humans do such work was suboptimal in the first place.
>> If it is then why don't we have tele-operated rigs
>> running all over it now?
> Because we no longer can go to the Moon. You would first
> need to expand DTN-capable Internet networks to lunar
> orbit (there are experimental Cisco boxes in LEO already),
> and be able to soft-land instruments and robotics platforms.
>> For an SPS in GEO
> GEO is too far. And already too crowded.
It is a very large volume and not nearly as crowded as LEO.
>> the break even size is around 2 - 4 GWs.
> I have not seen an EROEI calculation for a
> lunar launch, but any self-rep system with a
> closure over unity is the ultimate free lunch.
Self-rep? Dreamer. :)
>> That is a very large space structure to
>> assemble and maintain.
> You would want as many small (>100 m) platforms
> as possible in as low an orbit as possible.
> You need 2-3 of them permanently in line of sight
> for a smooth handover. You'll need hundreds to
> thousands of these.
You are station keeping these how? At what altitude? Hundreds of thousands of such objects are not a navigational space hazard to from earth surface why?
> You would also use them to kill GPS, Iridium,
> and satellite Internet providers. Later, cloud
> services. And so on.
Are there some design specs for such that address all the issues? Iridium and others have tried for such approaches to a subset of the problems without much success. How would this be different?
>> Molecular assembler? Fine. But Drexler, Merkle,
>> and Frietas seem to be predicting no less than
>> three decades to get to machine phase. I don't
>> think we can wait that long to exploit near-earth space.
> I see you haven't read the link. The full-text online
> book is a literature review of self-replicators in general,
> including space-based manufacturing.
It is speculative future stuff requiring many steps we do not have now and will not have for at least a couple of decades according to some of the same authors. If you found something different in the paper where such things can be built in this decade then please point them out. My quick scan did not find them.
>>> At this point, it's largely a question of budget.
>>> There's a second Moon race of sorts on, Japan,
>>> India and China (and Europe) being the main participants.
>> Personally I think the moon is the wrong target for
>> doing near earth space infrastructure. There is more
>> variety of useful and lucrative material in near earth
> Material transport is to be avoided, initially.
> Material trasport to Earth will never amount to much,
> in my opinion. There is an incentive to move heavy
> industry and associated contamination outside of
> Earth's ecosystem, and only deploy prefabricated
> and fabricated components. Also, if we are at that
> point, the human era is shortly over, anyway.
> You'll notice that the ecosystem itself does little
> matter transport, prefering to utilize materials
> in situ.
The point though is where you get the material and delta V to build out space infrastructure. This is more easily accessible in shorter term from mining near earth asteroids.
> The nearest (2.5 s relativistic pingpoing) rock is
> the Moon. It doesn't have microgravity, which is an
> advantage if you're learning the ropes.
Relativistic ping pong is not the best/only way to measure "near" in terms of exploitable characteristics.
> After you've got nearly autonomous system and experience
> in microgravity manufacturing, the whole solar system
> is yours.
>> asteroids more easy to get to. No problem with doing
>> both but I think the bounty of near earth asteroids
>> is very seriously overlooked.
> I used to think that the asteroids were the way to go.
> However, the Moon is the gateway.
Why? And why not use the asteroids as step one to rich inner system space infrastructure before or at least in parallel with exploiting the moon? Heavy metals are not known to be all that available on the moon. Neither are as easily reachable volatiles. I don't think it is an either or but I think it would be very irrational to not exploit the near earth asteroids.
>>>> how you are going to create the ability to mine,
>>>> process, assemble and maintain all this infrastructure
>>>> and in what steps.
>>> The basic idea of ISRU is to reduce mass transfer.
>>> It's pretty obvious that you don't need to fabricate
>>> control logic locally, and for e.g. PV panel production
>>> the silicon (or other materials) can initially be
>>> transported from Earth.
>> At $2000 - $10000 / kg?
> Thin-film CdTe is some 10 g/m^2. So a ~kg buys
> you around 100 m^2 of solar panels, if sputtered
> on regolith glass. If you're bootstrapping
> power plant capacity to power your manufacturing
> capacity, any kg less reduces your bootstrap costs.
> I'm assuming >100 kg packages semi-soft-landed
> (300 g would do) on lunar surface.
>>> We know there's a lot of
>>> volatiles at the pole(s), which is incidentally
>>> one of the few places in the Solar system where
>>> ancient crater cryotraps sit right next to the
>>> peak of eternal sunlight.
>> There are a lot of volatiles in your average near
> Well, there's a lot of hydrocarbons on Titan.
>> earth asteroid and a lot cheaper to extract.
> We know it will be very cheap to extract, microwave
> heating and condensing in adjacent polar cryotrap
> will do.
Lunar makeup does not include as high concentration of many useful resources as the asteroids. High concentration makes for cheaper per ton extraction / refining.
>> Volatiles for delta V to move the lot (or the
>> extracted materials you wish) to where it is needed.
> We need volates for wet industrial processes (e.g.
> electrolysis and hydrogen for oxide reduction,
> and such) and maybe some oxygen/hydrogen to
> make it to Earth's atmosphere.
You need volatiles for delta V to do significant inners system space infrastructure and travel.
>>> So that looks like the best place to start.
>>> The bootstrap won't be completely scripted,
>>> since there will be always surprises, improvisations
>>> and optimisations.
>> We don't have the means to do this yet,
> If we wait much longer, we'll never will.
We cant' go faster than we have the means to do so. What are the missing pieces? Can we lay them out and set up web and literature crawlers to note when each (or suitable substitutes) comes online? Do we have or can we find mission experts to create at least plausible skeleton plans? I am less concerned with expanding beyond the solar system dreams than with realizable R&D and workable engineering/capitalization plans from where we are right now. Yes, let us dream big but also ground these dreams in actionable steps.
>> principally we don't have cheap enough
>> launch or the assembler/maintainers in
> Chemical rockets to make it to LEO and
> plasma thrusters to make it to low lunar
> orbit are all we're going to get.
There are non-rocket means that may be plausible and cheaper. LEO is not the place of primary interest, it is only a transfer point if we are after building out near earth and lunar infrastructure. It is great for some projects effecting earth only but not for much more as I see it.
> So your only other variable to minimize
> the total number of tranfers, and mass
> trasfered. That is a function of
> telecommunication, computation, and
> All of this can be done down here.
> But for 1/6th g you can simulate the Moon
> environment in lunar simulators, at a tiny
> fraction of costs it would have cost you to
> test-drive your gear under real conditions.
I don't want to be stuck in a 1/6 G gravity well any more than in a full G for very long.
>> space or on the moon. They can't be
>> human in a timely manner in the quantity
> There's no need for humans on the Moon for
> the foreseeable time, if ever. I do not
> think there will be permanently manned
> presence outside of the inner solar system
> (Moon and Mars).
Moon, Mars, space colonies. If you have ample materials in near-earth space then building habitats and manufacturing centers in the LaGrange points becomes tractable.
> You want to go to the stars, you have
> to lose this mansuit.
>> needed. Thus, robots - much better robots.
>> More than a few humans are too expensive
>> and difficult to maintain in space or
>> on the moon until substantial infrastructure
>> is already in place.
> Yes, robots. And then, robots which are
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