Solaren corporation has signed a deal with Pacific Gas & Electric to orbit a 200 megawatt solar power satellite by 2016.  I mention this not because the news is amazing (it was inevitable, really) but because their plan gives me some nice numbers to plug into my Verne gun calculations. 

You might remember my enthusiasm over Next Big Future's recent discussion of Project Orion and the spinoff notion of using nuclear bombs to loft very large payloads into space (wheeee!).  I called this idea the Verne gun in a feeble public relations attempt.  Anyway, Brian Wang's calculations over at NBF gave a figure of 280,000 tons as the lift-capacity of a single 10-megaton bomb.  At the time, I suggested using ten or so of these suckers to lift an entire continental powersat infrastructure into space.  But I didn't have hard numbers about how much mass equaled how much power.

Solaren have conveniently stated that their 200 megawatt, self-assembling power transmitter could go up in five launches of 25 tons each.  Solar power satellites are far more efficient per-solar-cell than ground-based plants, so they have a much smaller industrial footprint and almost no environmental footprint at all.  They run 24 hours a day.  So that means that the engineers at Solaren can do 200 megawatts of baseline power with 125 tons orbited.  To put it another way:

1 gigawatt baseline power = 625 orbited tons

Launching this much mass using conventional rockets is expensive, but obviously not entirely out of line, or they wouldn't be doing it.  But, here's a question:  how much baseline power (97% uptime) could be orbited using a 10 megaton Verne shot?  The answer: 448 gigawatts.  

The United States currently uses 4 terawatts of power per year.  About half of that is coal.  So four firings of the Verne gun could orbit enough power to obsolete the entire American coal-power system.

The big problem wouldn't be radiation from the launches (which would be effectively zero) but the astronomical insurance costs attendant on putting so many eggs in one launch basket.  Maybe a few dozen 100 kiloton shots would be better...

With the addition of its final set of solar panels, the international space station is slated to become the second brightest object in the night sky--brighter than Venus.  Now, admittedly the ISS is the size of a football field, but it's also three hundred kilometers away from the Earth directly above the plane of its orbit--but much further away for most of the people who see it.  Thousands of kilometers, for most of us.

Consider this:  on any given night, you can look up (if you're not in a city that already drowns the stars) and see satellites.  They're hundreds of kilometers away, and the biggest are no larger than a compact car--yet you can see them.  Most are the size of a barrel, but perfectly visible.

Consider Bradley Edwards' ribbon design for the space elevator cable.  This would be a meter or two wide and curved, so that it is effectively visible from all angles.  So it's about the width of a barrel, but infinitely longer.  Its reflective surface over one kilometer's distance would be at least as great as the ISS; but please multiply that light output by 35,000 because that's how many kilometers long it would have to be.  A Hoytether (open meshwork) design would presumably reflect less, but how much less?

You could paint the ribbon black.  Then again, how much would a coating weigh that had to cover 1 meter x 35 million meters of area?  The black coating would heat the cable because the sun is so intense in orbit, so you wouldn't want it to be totally absorptive.  But here's the thing:

The moon is black.

Actually, overall the moon's surface is about the shade of an asphalt highway. It absorbs almost all the light that hits it.  The moon appears pearly white to us only because of the tiny fraction of light that's reflected off the lunar blacktop.  So even a mostly-black ribbon would look brilliantly white to us on the ground.

As if all this were not enough, the only practical means of powering the climber cars (which would be visible too) appears to be multi-megawatt lasers, aimed at solar cell arrays on the climbers.  As Wikipedia puts it:

The proposed method is laser power beaming, using megawatt powered free electron or solid state lasers in combination with adaptive mirrors approximately 10 m wide and a photovoltaic array on the climber tuned to the laser frequency for efficiency.

So, the climbers are in the cross-hairs of, essentially, a set of a huge spotlights.  Maybe you could use infrared or ultraviolet lasers, but if not, then even for the most efficient solar cells (40% or thereabouts) 60% of the laser light will be absorbed or reflected.  Add to that light from the sun reflecting off the (presumably large) collectors, and you get something fiercely bright climbing the already bright cable.

This issue doesn't just affect the space elevator, by the way.  It's also relevant to any substantial effort to place solar power satellites at geosynchronous orbit.  Their immense surface area would pretty much guarantee that they'd shed a vast amount of light on the Earth.

But why should we care?  Here again we can refer to Wikipedia, in its entry on light pollution:

Life exists with natural patterns of light and dark, so disruption of those patterns influences many aspects of animal behavior.  Light pollution can confuse animal navigation, alter competitive interactions, change predator-prey relations, and influence animal physiology.

...Studies suggest that light pollution around lakes prevents zooplankton, such as Daphnia, from eating surface algae, helping cause algal blooms that can kill off the lakes' plants and lower water quality.

Lots of other life forms are affect--everything from birds to frogs.  It doesn't take very much light to have a big effect. So, in the absence of any direct physical effects, the space elevator would still have a large, if not catastrophic, ecological impact.

I wish this weren't true.  I'm a big fan of the elevator, and an even bigger fan of solar power satellites.  But the devil, as they say, is in the details.  If these structures cause the amount of light pollution I'm suggesting, then they are very far from being green options for energy and transport--regardless of how much carbon they may offset.

Further to the discussion about Brian Wang's treatment of Orion and its offshoot, the Verne gun, if you look at the comments to my previous post, Adam Crowl suggests that peak acceleration for Brian's gun would be about 3700 gravities.  He also suggests ways of reducing that, primarily by using a nuclear charge to energize hydrogen gas and have that push the ship.  (I'm not sure that's the most efficient way to go, though, because the Orion design depends on the efficiency of energy transfer to the pusher plate and requires close proximity to the charge.)

In any case, this figure of 3700 g's suggests something: some things would be able to take it (like hardened electronics, tight rolls of thin-film solar cells, and liquids like water or rocket fuel) but others (like people and furniture) would not.  In one of Brian's latest posts, he talks about the Mercury laser, which might make practical laser-initiated fusion happen.  This piece makes me wonder what the total mass of the system minus the supporting building structure would be (because that bears on how practical it would be for fusion powered spacecraft) but also reminds me that laser launch systems have only been waiting for this one development to become practical. 

So here's the plan:  launch a few hundred thousand tonnes of rugged stuff using the Verne gun, and send up the rest a tonne at a time using a laser launch system.  You can even run the laser launch system off renewables if you want to be green; and after the first few launches, you end up running it off beamed power from the first solar power sat you put up.  True bootstrapping through hybrid launch technology.

I have to admit I got a bit ahead of myself in the post below, in which I renamed the nuclear cannon the Verne gun and described some of what you could do with it.  As it stands, the idea would only work for cargoes that could withstand tens of thousands of g's of acceleration---which in practice would amount to fuel, raw iron and a few other simple items like that.  Still valuable to orbit, but a bit limiting.

So, here's a proposal to refine the idea a bit:  the sabot.  In this variation of the Verne gun, you don't try to reach escape velocity.  The blast that sends up the ship only needs to loft it about 100 kilometers---above the atmosphere, but not into orbit.  The bulk of the ship's mass is in fact acceleration padding--a sabot or shell around a more conventional rocket-powered craft.  After an initial acceleration (still on the order of hundreds of g's at least) the sabot separates from the cargo at 100 kilometers, lightening the load and permitting the contained rockets to fire.  This lighter craft then enters orbit under rocket power.

An alternative to rockets would be to catch the ship at the top of its trajectory using an orbiting tether (a huge one, if we're catching tens or hundreds of thousands of tonnes!).  In either case, the acceleration shielding for the initial launch falls back into the ocean and what enters space is pure cargo.

Using a sabot might allow us to launch more fragile cargoes than the straight shot version.  I now doubt that you could launch, for instance, solar power sats without a sabot, though sending up a space elevator would probably still work.

Toby Buckell informs me, by the way, that Niven and Pournelle used the idea of the nuclear cannon in their alien-invasion novel Footfall.  Let's get precedent straight here---as far as I know, they did it first in science fiction.

Recently I talked about one of my favourite blogs, Brian Wang's Next Big Future.  He and his team are a veritable fountain of ideas, and this week they've outdone themselves with a series of pieces on Project Orion and its offshoots.  Now, I freely admit that they've done all the heavy lifting here (so to speak) but I'm going to take one of their ideas and run with it anyway.

A couple of the salient posts on Project Orion are The Nuclear Orion Home Run Shot, and Pieces of a True Nuclear Cannon.  Now, Orion was the 1950s-era American project to build a nuclear-bomb powered spacecraft.  Three facts stand out about the project:

1. It could have worked, and would have put unlimited amounts of mass into space for less than $1 a kilo.
2. The biggest vessel contemplated by the Orion team would have weighed 8 million tonnes, and would have been bigger than the Great Pyramid.
3. The sucker wouldn't have incinerated, flattened, and irradiated nearly as much real estate as you might think.

Still, for some reason the project was canceled around 1964.

In contemplating the glory that almost was, it's tempting to imagine what could have been accomplished with Orion.  One thought I had was that, well, maybe you could just use it once:  do the full-out 8-million tonne monster and use it to launch, in one shot, enough solar satellite infrastructure to obsolete every North American coal plant overnight.  According to a rational moral calculus, if Orion works it should be used in such a way, because the number of people who would die worldwide from the beast's fallout would be trivial compared to the number saved by reductions in air pollution from coal.  (Three million people die from air pollution each year; what they point out over at Next Big Future is that Orion could be calibrated to limit its fallout deaths to no more than a few dozen per launch, even for the biggest ship).

Still, there would be some place on Earth that would suffer from such a launch, and one thing we've learned is there is no truly "empty" land.  Even if our moral calculus could be extended to other species that would be saved by greening our power, it would be better if there were some way to launch such huge masses without exposing the biosphere to nuclear explosions and fallout at all.

There is.  I call it the Verne gun because frankly, a name like THE ATOMIC CANNON would just not go over well in certain circles.  In any case, the principle is the same as Verne's original idea, but using modern technology:  you set off a nuclear charge underground where the blast, heat, radiation and fallout can all be contained, and use Orion-type technology to direct its energy into orbiting a very big, very heavy spacecraft.  This vessel would experience hundreds to thousands of g's of acceleration--you couldn't put humans in it.  But Wang calculates that a 10 megaton bomb could put 280,000 tons into orbit with zero radiation escape into the biosphere.  Since dozens of bombs were exploded in exactly this way from the 50's to the 70's, we know this can be done.  And Orion's researchers proved nearly every one of their theories about Orion.  What they couldn't test at the time can now be simulated accurately by today's supercomputers, without the need for a test program.

Such an orbital gun could be used multiple times.  Here's what you could do if you could put 280,000 tons into orbit in one shot:

• Put 1.5 terawatts of clean solar power into orbit with less than ten launches.  Obsolete coal and petroleum power production with green baseline power, using less than a 10th the number of solar cells as you'd have to install on Earth to capture the same amount of sunlight.
• Orbit an entire space elevator with one launch.  Set it up, retire the gun, and get on with a clean space age.
• Do the same thing with an orbiting greenhouse infrastructure.  Drop solar-powered mass drivers on the moon to feed a continual stream of building material to the building sites.
  
• Orbit fuel depots to drop the price of conventional rocketry to orbit through the floor.  One shot and access to space for NASA becomes 10 times cheaper.
• Send up a telescope so big that it can image the continents of planets circling other stars.
  
• Put up one or more of those cool gigantic orbiting space station wheels that are showcased so dramatically in the movie 2001:  A Space Odyssey.
• Send an entire colony's worth of material to the moon or Mars.  With a second shot, put up an interplanetary cycler ring, tether launch system or other permanent mechanism for shuttling people to and from the colonies.
• Toss a couple hundred thousand tons of nuclear waste into the sun, where it won't bother us anymore.  (Trust me, the sun won't notice.)
• Launch an empty Orion ship, send its fuel up the safer space elevator, and send an expedition to Saturn, or a probe to the next star.
  

I'm not going to suggest orbiting a sunshade to head off global warming, because that's no solution for problems like ocean acidification.  --In any case, you can certainly think up other cool stuff we could do; and notice that some of these options, like orbiting fuel depots or a space elevator, can easily bootstrap us out of having to use the gun more than once or twice.

Oh, and of course, there's one more thing you could do with it, but since you'd need to get signoff from all the members of the nuclear club to use it at all, this one's a bit less likely:

• Orbit a huge frikkin death star platform with ATOMIC LASERS and MISSILE RACKS and RAIL GUNS and aim them at anybody you don't like.
  

If the Conservatives had come up with the Green Shift policy, I would be voting Conservative.  If the NDP had come up with it, I'd be voting NDP.  In fact, in Canada it's the Green Party that first developed the idea of a revenue-neutral transition from taxing income to taxing waste.  Who came up with it doesn't matter.  What matters is that it happen, and soon.

The fact is that tax plans like this are not new.  Germany has been employing a similar tax for ten years now, and Germany's record with green tech is stellar:  250,000 jobs directly relating to sustainable technologies is nothing to sneeze at.  Other countries that are either enacting such measures now or are intensively studying them include the UK, Portugal, and the Netherlands. 

The devil's always in the details, but tax shifts like this are fundamentally simpler than other measures the provinces are already planning, such as the cap and trade market for carbon that is a major goal of the Western Climate Initiative (which 70% of Canadians now belong to).  Tax shifting is simple:  the government stops taxing you for being productive, and starts taxing you for being wasteful.  This means more money in our pockets for at least two reasons:  first, the carbon tax is immediately offset by income and business tax reductions; secondly, making waste expensive gives companies incentive to become more efficient, and efficiency drives down costs.  This is why costs don't get passed on to the consumer, and it is why everything eventually becomes cheaper rather than more expensive.

When demand for fossil fuels increases, their prices go up.  When demand for renewables like wind or solar power increases... their prices go down.

You can have more money in your pocket while making a huge difference to the environment.  And this tax would not apply to gasoline.

The reason the Conservatives are complaining about the "Green Shift" proposal is that it would have been a perfect policy for them--more money all around with less of a hit on the consumer--but they didn't think of it first.