Classic space operas ignore the difficult realities of space travel, assuming that all the potential kinks have been worked out through and that future societies have developed new "black box" technologies (as in wormholes and their navigation, warp speed leaps through space, handheld devices that translate alien languages and diagnose obscure ailments on the fly, transporters that disassemble human bodies and reassemble them many miles away). Suspension of disbelief is willing but often strained.
With a new Star Trek film in theatres this week, I've been thinking about the question that most challenges my own suspension of disbelief. As someone who thinks more and more about the need for systems to be sustainable, and as someone primed by the "Spaceship Earth" metaphor, I want to understand how the Enterprise maintains a viable internal ecology. The ship spends most of its time in space, there seem to be few returns to planet Earth, and while much is made of the search for dilithium crystals, it's never obvious how basic life support issues - air, water, food, waste disposal - are handled.
As I was straining to engineer the sustainable Starship Enterprise in my head, I realized there must be an easier way: crowdsource! So we're having a contest, the winner of which will get a no-prize (nodding to Stan Lee and Marvel Comics) and be featured in an upcoming Worldchanging "roundup" post.
To win a no-prize, just describe a credible system for overall environmental sustainability and stability within the Starship Enterprise. Send your description to contest //at// worldchanging.com. Send no later than May 11, 2009. We'll post the winner by May 22.
Photo credit: flickr/jeffc5000, Creative Commons license.
Has Worldchanging sold out?
Great challenge so thought I'd add on a concept they used in the movie quite extensively but never explained how it worked too. The concept of the food replicator and I'm assuming that meant also a food and/or waste disposal unit as well. (funny never saw anyone go into or come out or even speak of a bathroom session or area in all those movies. I guess they just held it during each episode.)
We can then assume by extrapolation the same principle was probably used for air and purification as well. If they could create and rearrange entire eco and living environments in the holo-decks chambers they sure could do this for the star trek ship.
Remember how the units created food and it's utensils on demand from a few button pushes. That principle of creating and rearranging solid matter from computer stored atomic replication patterns has to be part of the answer you are seeking for a sustainable long range green spaceship.
Oh my kingdom for just one of those food replicators.
Of course the replication process would take huge amounts of energy, not to mention warp speed and the ship itself and it's huge weapons system all used energy, which was produced from those dilithium crystals colliding and/or helping mix, or acting as a catalyst in the matter/anti-matter chambers at the bowels of the engineering department of the ship.
So there you have it a sustainable environment from what was depicted as almost free unlimited energy.
This was fun thinking through,
TCM & Associates, Inc.
I see Robert (above) beat me to it--they have replicators that can directly synthesize matter from energy. Unfortunately, the Star Trek universe is filled with magical technologies that solve most of their problems.
Except seatbelts. I never understood why they don't have seatbelts, given that the "inertial dampeners" always fail. Or actual cybernetics or genetic engineering. For all its techno-fetishism, Star Trek generally treats anything that alters humans as pretty evil. Well, now I'm going off topic. :)
Even with the replicators, there are several points in the "canon" where they mention how the ships have to dock for maintenance and restocking (very unspecific tho) upon occasion.
But the point here is to exercise more imagination than the writers at Paramount, I suppose! :)
Congratulations to our contest winner, Tom Craver from Chandler, Arizona. Here's his entry in full:
"The Enterprise does things by brute force, loosely modeled on the nuclear powered air craft carrier Enterprise. In other words, Enterprise is based on a 1960’s vision of the future, where energy was expected to be incredibly abundant. That future could still happen, out in space, or if human population eventually retrenches to sub-billion person levels, or if we discover some cheap and clean source of energy, such as aneutronic fusion power.
When you have a really abundant energy supply - nuclear or anti-matter in the cases considered - pretty much everything else becomes easy. You can filter and freeze and boil and otherwise process to recycle air and water all you need. The original starship Enterprise simply relied on carrying a large supply of food – again following the aircraft carrier model. Wastes could be partially recycled, or simply dumped into a convenient sun, or “beamed down” at the next port of call, to be processed. Later they added the matter replicator to recycle wastes into food and other goods - probably after someone pointed out that it was an obvious extension of the magical matter transporter technology they’d had from the first in the series.
Now if you are actually looking for something on which to model systems for “Spaceship Earth”, you might instead focus on the more realistic idea of a ‘generation ship’ – i.e. a star ship that takes centuries to deliver colonists to another star system, using existing or very near future technology. No warp drive, no matter transporter/replicator, no anti-matter or even fusion power, no nanotechnology, no other technologies that we don’t have at least a good idea how to make today. That’s not completely fair, since we will almost certainly develop *some* new technologies that could make a “Gship” work better, by the time we might consider launching one. But it’s a reasonable place to start from, and ensures a better match to Spaceship Earth today.
Once again, the energy supply is central to the design. In deep space, the Gship won’t be able to use solar/wind/hydro/geo power, and certainly couldn’t rely on fossil fuels. That pretty limits them much to nuclear power. We’ll ignore fusion power for the moment since we don’t know how to do that yet – though there are signs that we’re finally getting closer. We will just assume the Gship would use nuclear fission power.
But current fission plants only consume a small fraction of the energy available in Uranium – leaving the rest to slowly decay away over millennia as “radioactive waste” (mainly due to a ban on fuel recycling). There are new “deep burn” fission plant designs that will consume nearly all the available fission energy, and thereby produce much less radioactive waste with a shorter half-life. So let’s take that as a starting point – cleaner, more efficient nuclear fission, providing sustained, reliable, long term power. The Gship would have multiple small fission plants for redundancy – at least three, perhaps five if the ship is large enough. And it will need to have sufficient industrial capabilities on board to rebuild the nuclear power plants, as we know that exposure to neutrons tends to degrade metals in nuclear power plants, and cooling systems can corrode. In other words, for this aspect of the Gship, “sustainability” requires maintaining adequate technological prowess over centuries in a closed ship – which makes it primarily a sociological/psychological issue.
Despite having more efficient nuclear fission plants, the Gship can only carry so much nuclear fuel, and will need enough to last 100 or 200 years as it crawls slowly between the stars. So unlike the Enterprise, a Gship needs to use energy as efficiently as possible. So Gship design will be all about efficiency and recycling. Of course, you may not consider nuclear power “green” enough for Spaceship Earth, but at least with the new generation of nuclear power that is becoming a reasonable point to debate – especially as more and more we’re recognizing that “green” energy technologies (wind, hydro, solar, etc) can have large environmental impacts due to the scale they typically need in order to tap relatively diffuse energy sources.
The first thing the Gship designers need to consider is temperature regulation. With a nuclear reactor and living people and all their support systems on board, staying warm will not be a problem. Eliminating heat will be the focus – the Gship will be designed with large surfaces to radiate heat away. On Earth, we’re stuck with a spherical atmospheric interface to space, and we get a copious supply of sunlight adding heat. About our only option is to control how much heat is produced or retained near or on the Earth’s surface. Fortunately, the size of the Earth and its atmosphere, and the influence of solar irradiation and naturally existing atmospheric components, dominate Earth’s thermal regulatory system. There are things we can do that will turn the temperature up (or down) a bit, but we have to work hard at it. If one were to think of all fossil fuel use to date as if it had been a deliberate effort to warm the planet by increasing carbon dioxide, we have expended an incredible amount of effort with relatively minor results. That’s the good news. The bad news would be that we might have to work about that hard to remove the added carbon dioxide if we want to turn the temperature back down. So the Gship designers have it a bit easier than “Eship”.
With a general approach to temperature management figured out, the Gship designers would probably think about the air supply next. In this, they have a significant advantage – they can use heat radiators exposed to space and kept at about 194 degrees Kelvin, so that carbon dioxide can simply be frozen out of the air. The dry ice can be collected into closed chambers and allowed to warm to become a high pressure liquid that will pump itself around the Gship for cooling. But ultimately the CO2 needs to be processed into food, to close the cycle. (There’s more to air processing, such as filtering out dust, pyrolyzing organic molecules, and so forth – but basically this comes down to having systems to scrub the air of pollutants – an engineering task, not something requiring new science. On Earth, we can generally just limit the amount of pollutants we introduce into the air, and Earth’s biosphere will eventually take care of the rest of the cleaning job.)
Human wastes could be dealt with in a variety of ways, but the primary approach is to efficiently remove all water, then pyrolyze the remaining solid wastes to a sterile ash and steam, carbon dioxide and nitrogen. The ash would mostly consist of trace minerals that would be used in synthesizing food. To minimize long term metal accumulations in the system, which could become poisonous, most food and waste processing equipment would need to be ceramic or glass lined – or there would could be a metal leeching system. Certainly metals like lead and mercury would be kept away from those systems and any passenger contact.
The Gship designers would be foolish to rely on ordinary plants to do their carbon dioxide and other waste processing. Creating a balanced ecology large enough to handle all conversion of CO2 and wastes to food and clean air, and continue doing it for centuries in an artificial environment, is too much to expect. Plants are simply too inefficient, and too subject to problems like disease and insect infestations. Assuming your basic power supply is electricity, you would need to convert the energy to light, then the plants would convert a fraction of that light to chemical energy, which they would normally use to build stems and leaves and finally some food – if you’re lucky.
A more efficient approach to food production and CO2 recycling could make use of power plant “waste heat” to drive chemical reactions producing organic molecules. That would likely require a combination of conventional chemical processing, and use of organisms such as those found in deep sea vents, to produce edible sugars, starches, fats, proteins, etc. Suitably combined, those could be directly consumed, forming the bulk of diet for passengers. However, people will probably also want conventional fruits and vegetables, and some real meat. And the passengers would want to maintain a “semi-natural” area – perhaps a low-gravity “garden dome” – where plants can be grown and appreciated. However, the food productivity of such a dome would be relatively low for the energy input.
One compromise approach, providing “natural” fruits and vegetables, would require the use of genetically altered plants, that would grow no leaves or stems – just “Fruits And Roots”. Instead of depending on photosynthesis, FAR plants would be hydroponically fed “plant food” – basically the same organic chemicals produced by photosynthesis, primarily ATP (adenosine triphosphate) and sugars that can be broken down to ATP. ATP can be produced by chemically combining adenosine diphosphate and adenosine monophosphate and CO2 – the components that ATP breaks down into, which can be collected from the altered plants and recycled – to supply the energy a plant needs to grow its fruit. (Another variant on this would be plants genetically altered to directly use electricity instead of sunlight to generate ATP, but this is a bit more speculative.)
Back on planet Earth, FAR plants could be grown in towers inside cities (and unlike unrealistic photosynthesis-based “tower farm” schemes, they would not require such a large empty volume around them to admit sunlight that they almost might as well use flat fields). The “plant food” supply could be brought into town on rail cars from out-lying factories adjacent to nuclear power plants, where wastes are also processed. In this way, efficient food production could take place with minimal energy spent on production and transport, and minimal land area impact.
The main issue with this approach is the question of sustainability. So long as we can maintain a high level technological civilization, that should not be a problem. But as a “fallback”, shifting to such a system should be balanced by allowing a large amount of agricultural land to revert to wilderness, preserving genetic diversity in case a global disaster strikes that throws humanity back to a more primitive level. (The Gship would not have that option – but at least it doesn’t need to be able to sustain it forever – just until it gets to a new world.) Of course, eventually Earth would run out of fission fuel for nuclear reactors, and if fusion power is not worked out, it would be necessary to change over to a solar energy based civilization, but solar thermal chemical processing should still be able to efficiently generate the FAR plant food more efficiently than farming.
On a Gship, population would necessarily be tightly limited – and with a highly-productive FAR food production system on Earth, it would be necessary to insure that population is equally controlled, or soon there would be no room left for nature. As with the Gship, it appears that the most effective and humane method of encouraging population control is to provide education, jobs, and a high standard of living - but limit available personal space. This could be done on Earth by keeping cities high-rise, multi-leveled and compact (perhaps 1 km across), and planting a 2 km wide “park zone” between the high density cities. With plenty of natural scenery within easy walking or biking distance, fast transport between city centers, lots of public space to enjoy, and a city scale not amenable to high levels of crime, there would be little incentive to build or move to sprawling suburbs. Families would tend to limit the number of children they have, in order to avoid being over-crowded at home – but large public spaces could keep the city itself feeling relatively open and far more convenient than suburbs. Similar principles would be applied to a Gship, so that people never need feel trapped.
About 20 000 such cities, each with a population around 500 000, would accommodate ten billion people on 180 000sq-km of land, including the park lands. With efficient city-based food production, agricultural areas would largely be abandoned, as their economic purpose ends. (This has already happened in some US states, and mirrors what happened when powered farm equipment eliminated the need for large amounts of farm labor.) Such a city-system would also provide a means to allow Earth’s human population to slowly shrink back toward perhaps 1 billion – by tearing down buildings (and eventually cities) to keep available private space per person constant. A similar “excess capacity, artificially limited” approach would be needed on a generation ship, in case some disaster reduces available resources.
Overall, the generation starship model stands as a better model for Spaceship Earth than the aircraft carrier/starship Enterprise."