Showing posts with label space technology. Show all posts
Showing posts with label space technology. Show all posts

Friday, January 4, 2019

Revisiting a Heated Debate

Concept of a solar reflector in high orbit.

Once upon a time, the debate over global warming and climatic change was mildly amusing to me. I could point out the false assumptions, the inadequate science, the contrarian historical evidence, and the typical human arrogance wrapped up in the matter, but I’ve grown very tired of it all now. As I noted several years ago, the obvious and most practical “solution” is already at hand, and I will revisit that in part today.

First, though, I put solution in quotes above because the most important potentially false assumption is that global warming is a problem at all. It may well be, but the facts are not yet in evidence for such a conclusion. Our models are inadequate and have failed to accurately predict outcomes thus far. Alarmism simply isn’t warranted.

Nevertheless, as I’ve previously stipulated, climatic change is something we should be concerned about. There is ample historical evidence for this, and in the longest term, we will have to actively manage the climatic conditions of our habitats, wherever or whatever they may be, if we would have human life and civilization continue indefinitely into the future. The short-term risks, though, are minimal and probably self-correcting.

The real problem, in my opinion, is that legitimate scientific inquiry and concern have been co-opted by political factions that are anti-capitalist and to some degree anti-human. They would slow, halt, or even reverse economic development for a variety of reasons, ranging from misguided environmentalism to outright misanthropy. These factions have spread the dubious alarm and fanned the flames of fear to engender public support for their political goals—and if their most radical proposals are enacted, billions of people will have to die. We will have replaced a remotely possible climatic catastrophe with a very certain political catastrophe.

For the most part, the way to mitigate potential climatic disasters is to keep doing what we have been doing throughout much of the modern era: lifting more and more people out of poverty through global economic development, reducing environmental pollution through improvements in energy technologies, and adapting to ecological changes when necessary. While our times are historically exceptional, these processes aren’t anywhere close to their theoretical limits. Taking the optimistic view, human civilization is only at the end of its beginning.

No! We’re at the beginning of the end! If we don’t do something right now, global warming will lead to mass extinctions and render the planet uninhabitable! Or so the alarmists would have us think. This doomsaying would be laughable … if it weren’t becoming the mainstream narrative believed by so many otherwise reasonable people.

That brings me back to the most obvious and practical solution to the technical problem of climatic management. The primary driver of climatic effects and cycles is solar radiation, sunlight. If we want to control or at least manage the terrestrial climate, the simplest and most direct way would be to control insolation, the amount of sunlight that reaches Earth’s surface.

There are several so-called geoengineering proposals that could achieve this, but the safest and most straightforward would be a series of orbital reflectors or shades. A constellation of such satellites could regulate global temperatures in a dynamic and very controllable manner, decreasing or increasing insolation as required. It’s a solution that would be both elegant and permanent.

The cost of such a program would not be insubstantial, but it wouldn’t be outrageous either. The technological concepts are decades old and would require no scientific breakthroughs to implement. I expect that initial development and deployment of the system would require less than $100 billion. Ongoing maintenance should be considerably less expensive, and follow-on benefits could likely repay the investments.

Solar-power satellite (explainingthefuture.com).

An array of solar reflectors would work well in conjunction with another proposed space-technology asset, the solar-power satellite. A fleet of these spacecraft could collect solar energy in space and beam it as microwaves to receiving stations, where it would be converted to clean electrical energy. While certainly not the only way to improve solar-power generation on Earth, space-based collection and re-transmission would overcome the reliability/availability problem that local ground-based collectors will always face.

Solar power holds a lot of promise even without on-orbit generation, but it probably can’t supplant hydrocarbon fuels in all applications. The real breakthrough in energy technology will be controlled nuclear fusion. Effective long-term implementation of that technology will also almost certainly require the exploitation of extraterrestrial resources, but the implications of essentially unlimited energy are staggering.

The availability of energy is at the root of all economic systems. The modern economic revolution is due in large part to the high energy density and relatively easy accessibility of our hydrocarbon fuels. Again, despite the doomsaying, petroleum is not going to be exhausted anytime soon. In fact, given unlimited energy, non-terrestrial resources and high-energy conversion methods can deliver virtually endless supplies. That’s when pollution and climatic effects should become our primary concerns.

A fusion-powered infrastructure would open a range of possibilities. Indoor, climate-controlled farming would become viable almost anywhere on the planet … and beyond. High-intensity water-purification and desalination processes would become affordable. Pollution reduction and capture technologies would become similarly inexpensive. And, of course, as basic survival needs became vastly easier to meet, societies would have more wealth to direct toward solving secondary and tertiary social problems.

In fact, the chief dilemma human civilization will face in the future may be surviving its own prosperity.

Wednesday, February 27, 2013

Relative Frequencies and Magnitudes of Bolide Explosions and Impact Events

The Great Daylight Fireball of 1972.

In light of the destructive bolide explosion over Chelyabinsk in Russia earlier this month, I have reviewed the recent history of meteoric events. From A.D. 1908 to 2013, there have been 11 confirmed events with potential explosive equivalencies greater than or equal to 10 kilotons of TNT. These are summarized below and suggest an observed frequency of such incidents that is somewhat higher than previous conservative predictions.

Eight of the observed explosions or impact events occurred over the greater Eurasian expanse. This continental zone includes just over 10.3 percent of the planet’s surface area. Extrapolating from these data yields an estimate of about seven such intermediate incidents per decade, which is not much lower than the number allegedly observed by military satellites. During the 105-year period bracketed by the Tunguska and Chelyabinsk explosions, there were also at least four bolides that exceeded 100kt equivalencies.

1908 Tunguska Event 15 Mt
1930 Curuçá River bolide explosion 5 Mt
1932 Arroyomolinos de León bolide 190 kt
1947 Sikhote-Alin impact 10 kt
1972 Great Daylight Fireball 80 kt
1993 Lugo bolide explosion 10 kt
1994 Marshall Islands Fireball 11 kt
2002 Eastern Mediterranean Event 20 kt
2004 Antarctic bolide explosion 12 kt
2009 Sulawesi bolide explosion 50 kt
2013 Chelyabinsk bolide explosion 500 kt
2016 South Atlantic fireball 13 kt

The Great Daylight Fireball of 1972 was caused by a near-Earth asteroid that passed harmlessly through the atmosphere over North America at least 35 miles above the surface. Estimates of its potential damage vary wildly, but I have selected a number in the upper range. Given the speed and luminosity of the bolide, had it grazed the planet at a more acute angle, I expect that the results would have been spectacular and potentially devastating.

As the Chelyabinsk explosion has proven, these intermediate objects present a very real danger. They are smaller, harder to detect, and much more common than the potential doomsday asteroids we can spot now. And we still lack the infrastructure to stop either of these threats.

Updated to include the South Atlantic fireball of 2016, which exploded several hundred miles southeast of Brazil (http://neo.jpl.nasa.gov/fireballs/).

Monday, June 18, 2012

Ending a Heated Debate

A few "geoengineering" possibilities.

I must confess that the debate over anthropogenic global warming (climatic change for those of you who’ve shivered through recent summers) has been entertaining. The only thing more amusing than human arrogance is even more human arrogance. Be that as it may, I think the time has come to end the debate.

For the record, human activity obviously affects the global climate. Of course, everything affects the global climate, so that information is not terribly instructive. Where do human influences rank among the various factors? Only the arrogant can provide a definitive answer. However, we should still acknowledge that solar output and orbital dynamics generally have the greatest impact on climatic cycles—an important fact that I will return to shortly.

Since it’s the popular thing to do, I’ll go ahead and assume that anthropogenic climatic change is a bad thing and that we should probably do something about it. Now, though, I will buck the trend and dismiss the mainstream solutions as atmospheric alchemy. Arbitrarily reducing carbon-dioxide emissions over the short term will have a very small effect on global temperatures and will be prohibitively expensive.

Dr. Bjørn Lomborg meets Vice President Al Gore.

Rather than spending hundreds of billions or even trillions of dollars for minimal benefit, why not spend only tens of billions on mitigation efforts and on general economic development? As Bjørn Lomborg has cogently argued, focusing on these goals would have a much greater positive effect at only a fraction of the cost. (Dr. Lomborg is also rightly critical of proposed cap-and-trade schemes, which are ripe for corruption.) Yeah, that’s just wishful thinking.

So let’s spend a bunch of money on prevention, but let’s use science instead of alchemy. That brings me back to the sun, since controlling insolation would be the most cost-effective method of regulating global temperatures. Several “geoengineering” schemes have been proposed to accomplish this goal, but one stands above the rest.

The International Space Station.

A constellation of solar reflectors in orbit could shade the Earth and reduce global temperatures in a dynamic and very controllable manner. Such a system could probably be developed and deployed for the price of a low-budget manned Mars landing (around $50 billion). Ongoing maintenance of the infrastructure should cost significantly less than that. This would keep us within Dr. Lomborg’s suggestion of cost-effective solutions without the more politically difficult challenge of defeating the institutionalized corruption that stands in the way of his more noble goals.

An orbital sunshade may sound like science fiction, but it makes a lot more sense than mucking about blindly with complex atmospheric chemistry. Insolation could be decreased or increased as needed, allowing for long-term climatic regulation (and other potential benefits). Combined with ongoing pollution controls, a soletta program would provide an elegant and permanent solution to the problem of global warming.

So the debate is over. If you want to control the climate, control the amount of sunlight that reaches the planet’s surface. Doing so would cost a fraction of other less effective solutions.