[ExI] simulation as an improvement over reality
sjatkins at mac.com
Thu Dec 30 11:46:41 UTC 2010
On Dec 28, 2010, at 11:00 AM, Eugen Leitl wrote:
> On Tue, Dec 28, 2010 at 10:00:52AM -0800, Samantha Atkins wrote:
>>> It is quite obvious that once terrestrial photovoltaics
>>> deployment will run into high 10% there *will* be SPS
>>> constellations (built in situ from lunar material),
>>> and soon also telecommunication, computing,
>>> storage, quite literally becoming the cloud of nodes in
>>> Earth-Moon system (most of us should be able to see
>>> the beginning of this), and soon elsewhere.
>> That is not at all obvious.
> If we don't do that, we won't amount
> to more than a footnote in universe's
Sure. Someday. But not first to attempt to gain cheap and plentiful enough energy to keep our technological momentum up. We need that long before we are capable of deploying SPS systems in GEO and/or on the moon.
>> 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. Assuming you can get it out of the gravity well (or mine and manufacture in near earth space) then there is a huge need for workers / devices of some kind to assemble and maintain all that lot in GEO or on the moon. We don't have anywhere near that many astronauts and do not field 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.
>> 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 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.
> 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. If it is then why don't we have tele-operated rigs running all over it now?
> and there's already the incentive
> to augment remote control with (faster) local
> reflexes. The degree of autonomy will only
> increase from there.
>> to assemble and maintain such vast structures in space.
> The nodes themselves aren't particularly big.
> About the biggest part is electromagnetic launchers,
> which are strictly modular.
For an SPS in GEO the break even size is around 2 - 4 GWs. That is a very large space structure to assemble and maintain.
>> Until and unless we have major space robotics
> Major space robotics starts with decent
> Earth-side robotics. We have had some really
> nice progress in the last couple decades.
Sure, although space robots have additional challenges.
>> this will not remotely happen. I am very concerned
>> in my focus with how exactly we get from the nitty
>> gritty "here" to any sort of of interesting and fun
>> to fantasize about "there". Show me the path, especially
> See http://www.molecularassembler.com/KSRM.htm
> and the NASA ISRU (in situ resource utilization)
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.
> 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 asteroids more easy to get to. No problem with doing both but I think the bounty of near earth asteroids is very seriously overlooked.
>> 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?
> 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 earth asteroid and a lot cheaper to extract. Volatiles for delta V to move the lot (or the extracted materials you wish) to where it is needed.
> 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, principally we don't have cheap enough launch or the assembler/maintainers in space or on the moon. They can't be human in a timely manner in the quantity 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.
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