AHC: Space-based Solar Power is online!

[unclepatrick]

This is the 100 timeline that interested me enough to Subscribe to.
I am going to have to reread the posting before commenting. Interesting discussion.

[Michel Van]

Originally Posted by SunilTanna

You don't need to bring all the materials up from Earth when there's a ready made raw materials dump only 1/4 million miles way.

yes it sound very good to use the Moon as resource.
But it has very high cost over U$500 Billion, why ?

you need to launch all stuff not only in orbit, but also to moon and land it there.
then send astronauts to Moon, who build from that stuff factories, Habitat, nuclear reactors and a launch system.
Manufacture from raw material, parts and launch them into GEO
That's would be a Railgun or Mass driver http://en.wikipedia.org/wiki/Mass_driver
But for this infrastructure need really huge launch rocket like AMLLV with 1600 tons payload.
To launch the hardware, nuclear engine tugs, Lunar landers and there needed fuel.
and you need a lot fuel because the Moon has also gravity field.

is more economic to build parts on earth and launch it
or
look for a Asteroid in near Earth space and dock a factories on it, who start to build a SPS out of it.

[Dathi THorfinnsson]

Originally Posted by Michel Van

yes it sound very good to use the Moon as resource.
But it has very high cost over U$500 Billion, why ?

you need to launch all stuff not only in orbit, but also to moon and land it there.
then send astronauts to Moon, who build from that stuff factories, Habitat, nuclear reactors and a launch system.
Manufacture from raw material, parts and launch them into GEO
That's would be a Railgun or Mass driver http://en.wikipedia.org/wiki/Mass_driver
But for this infrastructure need really huge launch rocket like AMLLV with 1600 tons payload.
To launch the hardware, nuclear engine tugs, Lunar landers and there needed fuel.
and you need a lot fuel because the Moon has also gravity field.

is more economic to build parts on earth and launch it
or
look for a Asteroid in near Earth space and dock a factories on it, who start to build a SPS out of it.

ONeill wanted moon sourced materials to build sps to justify his l5 colony.

While his costs are incredibly optimistic, shall we say, his point that launching stuff from earth with rockets is EXPENSIVE and always will be. If you are building enough powersats to be worthwhile, launching once the mass needed for a lunar base, and using lunar materials to build your space infrastructure makes a LOT of sense.

If you arent building that many, theres no real point, except as a demo or prestige project, or thinly veiled military project.

[Shevek23]

Um, OK. Let's imagine the ASBs make us a nice Moon colony, to pick a population out of a hat, let's say it has 10,000 human beings living sustainably on it. Presumably they have whatever degree of infrastructure they need, enough greenhouses and solar panels and suitable pressure suits and radiation-sheltered habitats and sufficient water reserves and so forth, they are located wherever on the Moon this stuff would most logically have been developed. They know themselves to be Earth-related, say they are first generation and believe they were born on Earth and have emotional ties to wherever they think they came from.

So, wow, suddenly there's a permanent human presence in space for free.

We call them up on the radio. "Hi guys! Would you be so kind as to launch a whole bunch of metal and silicon into geosynchronous orbit around Earth so we can fabricate solar power stations? And oh hey by the way, it seems it would be damn expensive for us to even send up construction workers or feed them once there too, so would y'all mind sending out a big work team down there too to actually make the things for us? We'd really appreciate it!"

They call back "Well, gosh. That sounds like fun! Unfortunately, this living on the Moon stuff isn't entirely easy you know, we've got a lot of work to do just building more pressures and prospecting for the better metals and making sure we can find enough ice reserves to balance our losses plus of course our population is growing, gotta think of the kids too. Could y'all maybe offer us something to make it worth our while?"

Us: "Um, money? Money in the bank?"

Them: "Money's nice, but what can it buy us that we need up here? Could you maybe send us some water? We've got plans to go hiking out to the asteroids and bringing back a nice icy one, but that's a big project, one we'd have to put on hold to make your power plants, so if you could ship us some water we'd appreciate it. Also I haven't had any real coffee in 15 years..."

Us: We look at the options of launch systems we've developed so far, and groan. We look at the myriads of possible launch systems and get into catfights about what the real advantages and drawbacks of each are. We say

"Can we get back to you on that?"

Moral of the story--to benefit Earth people, we need systems to launch both cargo and humans to orbit and back, period.

Obviously in a real-world, non-ASB scenario where if there is going to be this useful moon colony, we have to first launch it, they have to be kept alive while they figure out how to develop Lunar resources to keep themselves alive, before they can turn to leveraging Terran resources into orbital production. It makes sense to me that on a sufficiently large scale of total investment, Lunar resources can indeed lower the total costs per unit. But only if we are making a whole hell of a lot of units!

With or without magic ASB colonies, we need to face the question of how to efficiently, economically get stuff into orbit. We may need to face the reality that the cheapest way possible still costs a pretty penny.

[MattII]

Originally Posted by Dathi THorfinnsson

While his costs are incredibly optimistic, shall we say, his point that launching stuff from earth with rockets is EXPENSIVE and always will be. If you are building enough powersats to be worthwhile, launching once the mass needed for a lunar base, and using lunar materials to build your space infrastructure makes a LOT of sense.

Except that lunar regolith is hugely abrasive, so you're going to need a colossal industry compared to earth, especially as you have to produce everything you need, including life-support equipment, much of which mother terra provides free of charge.

[SunilTanna]

Originally Posted by MattII

Except that that's even more costly, because now you're basically transshipping the thing into orbit via the moon.

Also, to do any good this thing has to be in GEO, LEO just won't cut it.

No you're not. You send a small automated manufacturing plant to the moon, as well as build a simple launch facility, like a catapult. Both operations are designed to operate with little or no ongoing support/replenishment from Earth.

The manufacturing plant mass produces solar panels, sticks them on the catapult, which flings them into Earth orbit.

In Earth orbit you assemble the panels into solar power arrays.

The panels are essentially free (or more precisely are a fixed cost regardless of how many solar power stations you build in earth orbit - so incentive to builds lots of power stations), since once you've made the initial investment in lunar plant, it costs you nothing extra to get more, since you don't have get them out of the Earth's gravity well.

[MattII]

Originally Posted by SunilTanna

No you're not. You send a small automated manufacturing plant to the moon, as well as build a simple launch facility, like a catapult. Both operations are designed to operate with little or no ongoing support/replenishment from Earth.

I'll give you six months at most before something screws up, and much less if you don't seal the joints properly and regolith gets in.

The manufacturing plant mass produces solar panels, sticks them on the catapult, which flings them into Earth orbit.

leaving aside the issue of repair, you'll still need humans up there for oversight and QC work.

In Earth orbit you assemble the panels into solar power arrays.

right, except you get the angle or power wrong by a fraction of a degree and that stuff is going to miss its target and spiral in towards earth, or else head out on an impromptu tour of the universe.

The panels are essentially free (or more precisely are a fixed cost regardless of how many solar power stations you build in earth orbit - so incentive to builds lots of power stations), since once you've made the initial investment in lunar plant, it costs you nothing extra to get more, since you don't have get them out of the Earth's gravity well.

Well, except the frequent repair parts for every bit of equipment that has come into contact with raw regolith.

[Michel Van]

Here data about Delta V to launch stuff in Orbit, GEO, Moon etc.

10000 meter/sec From Earth to low orbit for very heavy Lift rocket
here the payload is tugged to site with NTR or Ion engine
2300 meter/sec from Low to GTO (AndyC TL with Molniya orbit)
3800 meter/sec from Low to GEO
4800 meter/sec to moon orbit and back, with use of aerobraking in Earth Atmosphere
3200 meter/sec landing and start on the Moon
source Atomic Rocket http://www.projectrho.com/public_htm...et/mission.php

So higher the number so higher is need of fuel in orbit
12300 meter/sec from Earth into Molniya orbit - AndyC TL
13800 meter/sec from Earth to GEO or to a asteroid near Earth
18000 meter/sec use of Moon as Source with Chemical landers. with use of aerobraking in Earth Atmosphere
this number is for transport of Hardware to Moon, not transport from the Moon !
the SPS parts are launch with Mass driver from moon and make aerobraking in Earth Atmosphere to get in GTO
Here they assemble by robot to SPS module and tug in GEO. (because the parts fly true Van Allen radiation belt !!!)
http://en.wikipedia.org/wiki/Van_Allen_radiation_belt

[Asnys]

(Cough) That was AndyC's TL, not mine. I just endorsed it.

[AndyC]

Originally Posted by Michel Van

Here data about Delta V to launch stuff in Orbit, GEO, Moon etc.
2300 meter/sec from Low to GTO (Asnys TL with Molniya orbit)
http://www.projectrho.com/public_htm...et/mission.php

Cool. Looks like my wet-finger guess wasn't far off: From Encyclopaedia Astronautica, N-1 Basic Block A: 92.7 tonnes to LEO; Isp (vacuum): 311s

Gives a burnout mass of 43.5 tonnes for a 2300 m/s delta vee once in LEO.

[Michel Van]

Originally Posted by Asnys

(Cough) That was AndyC's TL, not mine. I just endorsed it.

UPPS : mixup,
i fix the post. sorry about that !