Today’s posting will fit into the general themes of the past couple of days, but will apply them to the issue of space development, which continues to be the focus of at least of cluster of brain cells when I have spare time.
Externalities
One of the issues of the past few days has been the issue of externalities – people performing actions that threaten the life, health, and well-being of others without having to compensate those people for the costs. An industry that produces externalities allows the people involved in that industry to profit from the destruction of the things that are of value to other people. In some cases, it takes their lives.
One aspect of space development is that it is one area of industrial development that it can easily be designed to produce few externalities.
Energy Production
In space, we can expect energy to come primarily from two sources; photovoltaic (the use of solar cells to convert sunlight directly into energy), and solar concentration (the use of mirrors to focus solar energy on a reservoir that turns liquid into steam which turns a turbine. Both of these forms of energy production in space has significant advantages over similar systems on Earth. There are no clouds. There is no night. There is no atmosphere blocking the full force of the sun’s energy.
There are no CO2 emissions to contribute to global warming, no spent nuclear fuel rods that need to be disposed of, no windmills to clutter the landscape and chop up migrating birds, none of the problems with being able to produce energy only when the wind is blowing or the sky is clear, no building of huge reservoirs behind dams, or any of those effects.
There is a problem with getting the energy to those who use it. Some systems advocate beaming the energy down to Earth using microwaves. This would generate some potential externalities. Yet, I tend to think in terms of using the energy where it is harvested.
Space Mining and Manufacturing
A mining and manufacturing ship pulls up to an asteroid. A great many asteroids in space appear to be gravel piles held together by their own gravity. They are a loose collection of dust and rocks waiting to be turned into something useful.
A space manufacturing center would pull up to the asteroid, take these chunks of rock, feed them into a grinder to pulverize them, send them through a (solar powered) processing plant to extract the useful materials (oxygen, water, methane, ammonia, aluminum, iron), and spit the mine tailings out the other end.
However, in space, there is no such thing as a ‘waste product’. One of the things that we need in space is radiation shielding. Radiation shielding consists of think walls of anything you have available which can absorb the high energy particles that otherwise contaminate space. Two aluminum sheets with this space debris sandwiched in between would make useful radiation shielding.
So, everything has a use.
As far as providing for the needs of earth, one way to do so is not to beam energy down to the Earth’s surface, but to drop refined mining material onto the surface – huge chunk of iron or aluminum that has already been mined and refined without contaminating one iota of Earth’s delicate environment.
Where possible, these things can even be molded into their final form in space – into I beams and sheet metal or whatever other materials those living on the surface of the future earth may have a use for.
Externalities in Space
Space itself will have some externalities. The externalities we need to worry about include orbiting debris – bullets and cannonballs travelling at 17,500 miles per hour that are the remnants of spacecraft that have disintegrated, either accidentally or intentionally. Those countries who produce this rubble are forcing others to endure a cost – either the cost of shielding their people and materials, the cost of losing their people and materials, or the cost of not utilizing these resources. These are externalities where those who engage in debris-producing activities expect others to pay for the harm that these people do.
Launch and entry back into the atmosphere will have some effects on the atmosphere, owever, , but it would take a great many launches and entries to compare to the damage done by earth-based energy production, mining, and manufacturing. One of the most useful rocket fuels is a combination of liquid hydrogen and liquid oxygen – which produces water – which is hardly a dangerous chemical to be putting into the air.
I do not know the effects of bring materials back down from space. Over 100 tons of meteors hit the earth’s atmosphere every day, and that seems to produce no ill effects. It will take a while for people to be dropping 100 tons per day down to earth, yet everybody who is interested in space development hopes for the day that this benchmark is passed.
A third externality to be concerned with is obstructing the view. Currently, we can see satellites orbiting the earth. If you look out after sunset or before dawn, while the sky is dark, you can see the occasional satellite drifting across the sky, like an airplane. Now, we do not hear a great deal of concern about airplanes polluting the view of space at night (or of the sky in daylight), and no reason to hold that the sight of a satellite is in any way worse than the site of a plane in the sky.
In these cases, of the externalities we already know to expect, only one of them is a serious threat, that being the creation of orbital debris. Those externalities affect people who put things in space, but have no effect on the earth, other than creating a barrier that prevents people from exploiting space as a way of putting less stress on the Earth.
Timeline
None of this should be considered a suggestion on what humans should try to accomplish in the near future. If that is the objection, then it misses the mark. I fully recognize that it would take a long time for space to reach this level of development. However, in that time, our need for space development might actually be higher than it is now. Over time, we are going to cut deeper and deeper scars into the living earth, unless we are pursuing alternatives that will allow us to leave the earth alone, to some extent.
However, like any investment, the sooner you start, the sooner you will see a return on your investment (if there is a return to be had). The sooner we invest in space-based energy production, mining, and manufacturing, the sooner we will have alternatives to cutting ever larger scars into the living earth.
As my birthday present, I would like to see the appropriate steps made in pursuing these options.
I am not asking for too much, am I?
Alsono Fyfe
ReplyDeleteHappy Birthday. I’d support your birthday wish.
If your wish helps to create the “SPACEHUMAN” backup that you referenced in your story then that alone is sufficient reason to agree with you, even if the effort is not economically neutral or beneficial. Stephen Hawkin would agree. The Moon, Mars and the moons of Jupiter are potential candidates for space settlements.
Orbiting power stations are a fascinating idea. A lot more power is needed if the rest of humanity insists on consuming energy at even a significant fraction of the rate that North Americans and Europeans do. The lack of an atmosphere in space or on the Moon makes both solar and nuclear power more attractive. We just need the technology to send the energy to Earth.
Only time will tell if asteroid mining will be economically viable. I suppose if we were to remove all externalities, the cost of mining on Earth might become sufficiently prohibitive that space mining is competitive. It is by no means certain because those asteroids are a long way off.
(1) We already have the technology to transfer energy directly from space down to earth - microwave transmission. The one issue that I see here is that transmitting large amounts of energy to the Earth's surface will make its own contribution to global warming (though significantly less than the contribution of greenhouse gasses). Note that global warming is not caused by the heat generated from energy production and use, but by the heat trapping effect of CO2.
ReplyDelete(2) In space terms, asteroids are not a long ways off. In fact, there are 600 asteroids closer than the moon. Now, 'distance' in space terms is not measured in terms of miles, but in terms of 'delta-v' (or 'change in veolocity' - the amount of energy it takes to get from where you are to where you want to be). There are 600 asteroids that require less energy to get to than the moon - and significantly less energy to get FROM than the moon because the asteroid has little gravity to fight against.
Some asteroids are not even that far off in terms of distance. We know the orbits of several asteroids that come very close to the Earth - and one (named 2004 MN4) that has a very slight possibility of hitting the Earth on Friday, April 13, 2029.
Microwave (and perhaps laser) power transmission from space to Earth is promising technology but it is an engineering challenge. The cost of constructing the solar power satellites in space is prohibitive because we have to get all the mass into orbit. An SPS is not yet economically viable so we have to consider it an experimental technology.
ReplyDeleteI do not argue that it is not worth the investment. I argue that we have to acknowledge that the investment will be substantial and there is little chance of turning a profit. Public funds should be committed to further research. The construction of an SPS using existing technology is probably a worthwhile international project and an excellent extension to the international space station.
I'm less optimistic about mining asteroids. The thought of mining factories travelling between asteroids is romantic but it may not be feasible. The energy input to reach them and match their velocity is significant. We might instead build permanent factories on very large asteroids and mine them more or less continuously. We then have to input energy to the product to match the velocity of the Earth. A super factory on the Moon is the third alternative but (as you mentioned) we have to overcome the Moon's gravity. The energy input (and thus the cost) is so high that I'm sceptical about space mining in the next century. I remain eager to be convinced that it is viable.
Again, Happy Birthday.
Happy Birthday, Alonzo!
ReplyDeleteSurprised you didn't talk about the space elevator. That would be a way to get finished product from asteroids back to earth safely.
Well, everything I talked about is an engineering challenge - some more than others. I consider the space elevator to be a bit too much of an engineering challenge right now.
ReplyDeleteAs for solar power satellites, I do not anticipate a near-term construction of a system that will transport megawatts of energy to earth. Please note that we already have solar power systems in space - though they are for local use. As local demand picks up, local supply will have to pick up as well.
Eventually (one of these days), somebody is going to get the idea of creating a single power plant and transmitting energy through space to those who demand it - from one satellite to another. This will lower the cost of launching satellites, because they will not need their own solar power generating system any more. It will significantly lower the price of space stations (for tourists and manufacturing).
Note: One use for a space-based research station that I would like to see is for the study of particularly deadly diseases. I would rather have people studying those in deep space than having laboratories here on Earth.
Anyway, I do see space-generated power used more in space than on Earth itself, at least in the foreseeable future.
As for space mining, I see no need for factories that travel from asteroid to asteroid in any short-term schedule. A mining center can hook up to an asteroid that is 5 to 10 km in diameter.
A 1 cubic kilometer asteroid will keep a space mining operation in business for a considerable amount of time. We're not talking about a few years in one location, but decades, even for a small asteroid.