NOTE: I am not a NASA employee. I do not speak for NASA or anyone else. None of these answers represent NASAÕs position, or my employerÕs position, or the position of any organization IÕm familiar with.
Most of this solar system is rock and radiation. ItÕs time to change that. We can bring the vast reaches of space to life, and gather immense wealth in the process. What, exactly, are we waiting for?
In the 1970Õs, the physicist Gerard OÕNeill with the help of NASA and Stanford University showed that it was possible to build giant orbiting spaceships and live in them. Are these projects still exist today for the NASA?
No. NASA is focused on exploration, not colonization. There is one, very small educational project concerned with colonization. Every year NASA Ames Research Center invites 6-12th grade students from around the world to design space settlements they would like to live in. These designs are judged by NASA engineers and scientists. The best receive awards and an invitation to visit NASA Ames. See http://lifesci3.arc.nasa.gov/SpaceSettlement/ for details.
Which would be the advantage and the disadvantages of the life in these space colonies in orbit?
Advantages: wealth, power, growth, survival -- and 0g recreation (there are also great views).
Wealth, power, and growth come from access to the resources of the whole solar system, rather than just Earth. For example, one small asteroid (3554 Amun) has $20 trillion dollars worth of metals. Solar power satellites can supply all the power we need with no greenhouse gasses (or any other emissions), no mining, and no drilling. The materials from the single largest asteroid can build space colonies with living areas totalling more than 150 times the surface area of the Earth.
If we do not colonize space, someday civilization will be destroyed. If nothing else happens, sooner or later a large asteroid will hit us. This has happened many times in the past (it killed the dinosaurs) and will happen again. Space colonies can help in two ways: 1. If Earth is seriously damaged, colonies can help us recover, just as people hurt by the tsunami were helped by unaffected countries. 2. Space colonies need materials to grow. They will have an interest in keeping watch for asteroids and comets that would otherwise strike Earth. When one is found, space colonists can tear it apart and use the materials to build more colonies, eliminating the problem and building valuable real estate at the same time.
0g recreation is just plain fun. Take a look at videos of astronauts playing in 0g at http://www.nas.nasa.gov/About/Education/SpaceSettlement/Video/. ItÕs a blast. Imagine if you had a lot more room and years to get good at it. For example, weightless soccer will be amazing. You launch yourself at the ball and the whole game is played in 3D, not on a flat surface like on Earth. Dance will literally go to new heights. Anyone can jump higher than Baryshnikov, and weightless and low-g dancers will doubtless take advantage of this new freedom of movement. Of course, many will only ask for some privacy and the right company. Honeymoon hotels will be a major attraction for orbital tourists, and space colonists will have access to them at all times.
The view of Earth from space is one of the most beautiful in the galaxy. Everyone who has seen it has been deeply touched. We should all get that chance. Early space colonists will have it every day.
Disadvantages: Particularly at first, each colony will be fairly small Š perhaps a few kilometers across with 5-10,000 people. Only later will colonies the size of a city become practical. Of course, travel to other colonies and Earth should be fairly easy.
The construction of these space colonies brings several important questions : which would be the processes of possible construction? With which materials? Which energy? And which protections against the solar radiations ?
The Moon and Near Earth Asteroids (NEAs) have all the materials we need.
The Moon has ample supplies of metals, silicon, and oxygen. These are available in large quantities in the surface dust, called regolith. Regolith covers the Moon to a depth of at least several meters, and probably much deeper. Unfortunately, the Moon lacks carbon, nitrogen, and has hydrogen for water only at the poles.
Fortunately, some NEAs are actually easier to get to than the Moon, meaning it takes less rocket fuel for a round trip. Asteroids are a much richer source of materials than the Moon. There is ample carbon and water, as well as plenty of metals and other useful materials.
In orbit, solar energy is plentiful and reliable. Unlike Earth, where night and clouds dim the sun frequently, in space the sunÕs energy is constantly available in all orbits except those very close to Earth. While low orbits are often in shadow, high orbits experience eclipse only a few minutes a year, and these are completely predictable. This is why most satellites use solar power. Plans for multi-megawatt solar power satellites have been developed to supply power to Earth. The same ideas and technology will be available for space colonies.
Radiation protection requires about 10 tons of material per square meter of surface area. This is sufficient to reduce radiation to acceptable levels. Almost any material will do. Lunar dust and/or asteroid materials left over from processing are good candidates.
Molecular nanotechnology seems to be a major improvement in manufacturing technology which will facilitate the construction of the space station. Why?
Advanced molecular nanotechnology can make things far lighter and more capable than is possible today. In particular, very advanced molecular nanotechnology should be able to make launch vehicles hundreds of times more efficient than todayÕs shuttle. This would radically reduce the cost of space colonization, making it practical much more quickly than otherwise.
If itÕs possible to build orbital space station, can we also talk about the colonization of the Moon or the planet Mars?
For colonization, the Moon and Mars are far inferior to orbit, at least at first. The biggest problem is gravity. The Moon has 1/6g and Mars 1/3g. We have no idea what will happen to children who grow up in reduced gravity, with one exception: they will be too weak to visit Earth. On Earth they will weigh 3-6 times what their bones and muscles are accustomed to. At best, they will be wheelchair bound. At worst, they will be bed-bound or die of heart failure. Never visiting Earth may be acceptable in a couple hundred years, but not for the first few colonies. How many parents will accept that their children can never visit their homeland, never attend the great universities of Earth, and never enjoy EarthÕs beauty and culture first hand?
Orbital colonies can be rotated to produce pseudo-gravity at any desired level, including 1g. If a child of an orbital colony gets a full scholarship to Harvard, they can go. If they are an Olympic class athlete, they can compete on Earth. If they are a world-class musician, they can tour the great concert halls of our native planet.
In addition, orbital colonies have continuous ample reliable solar energy, terrific views of Earth, weightless recreation, simplified 0g construction, much greater growth potential, and far easier access to Earth during early construction and to market their trade good.
Mankind will colonize orbital space first. Eventually, long after the first wave of colonization, it may make sense to live on the Moon or Mars.
Whether it acts of Mars or an orbiting station, these projects will be very expensive. How to find the financings, knowing that they will probably not be refunded before long years?
There are two ways to fund space colonization:
1. Decide that weÕd rather colonize space than kill each other. The U.S. alone spends over half a trillion dollars per year on defense. This buys a global military empire that could not protect us from nineteen guys with box cutters. Half the US defense budget would easily pay for space colonization in a few decades.
2. Barring a world-wide outbreak of sanity, we can fund colonies one profitable step at a time. One possible sequence of steps:
a. Sub-orbital tourism
b. Orbital tourism (especially 0g honeymoon hotels)
c. Low-g old age homes (no wheelchairs necessary)
d. Lunar mines for solar power satellites (multi-trillion dollar market)
e. Asteroid mines for mineral resources (ditto)
f. Orbital colonies
Transportation from Earth to orbit costs about $20,000 per kg and a few percent of all launches end in a large explosion. This must be fixed. In all of the space age there have only been a few thousand launches. If there had only been a few thousand airplane flights, if only a few thousand cars had been made, if only a few thousand train trips had ever taken place, transportation on Earth would be in a pretty sorry state. We need a lot of launches to get good at it. Tens of thousands. Millions. Launching communication, military, and science satellites will never get us there. The only market big enough is tourism. ThatÕs the ticket to cities in the sky.
Sub-orbital tourism is well on its way. SpaceShipOne, built by Burt RutanÕs team and funded by Paul Allen, can carry three people and has flown into space twice. RutanÕs team is now developing SpaceShipTwo, which is intended to fly paying customers in a few years. The cost is expected to be about $200,000 per flight at first, dropping considerably if there is enough traffic. While that is a great deal of money, many well-off middle class individuals could afford it if they really, really, really wanted to go. Say, bad enough to mortgage the house. A lot of wealthy people could afford it quite easily. If all goes well, flying thousands of tourists into space will give the space industry the experience and profits it needs to develop orbital tourist vehicles.
Orbital tourism has started, but in a very limited way. The Russians have flown two space tourists to the International Space Station (ISS). Both have had a fantastic experience. However, the cost is about $20 million. Large-scale orbital tourism will require much less expensive vehicles. Once available, long periods of weightlessness and literally out-of-this-world views are expected to draw thousands, maybe hundreds of thousands, of people into space for the experience of a lifetime.
These tourists will want nice hotels to stay in. Nice hotels require people to keep them that way. Some of these workers may become the first permanent residents in space. A few are bound to like it and be clever enough to find a way to stay on indefinitely. The first space colonists may be maids, bellhops, and musicians!
Once weightless orbital hotels are commonplace, it will occur to some wealthy people that gravity is a real problem for an aging, weak body. ItÕs gravity that puts you in a wheelchair. Low-g and weightless communities for aging billionaires may be the second wave of permanent residents in space. Eventually, the cost of these communities will come down enough for EarthÕs growing middle-class to enjoy them.
As mentioned before, solar power satellites can supply the Earth with far more energy than we use today without any emissions or mining Š on Earth. Lunar mines can supply the necessary materials. The Moon has everything we need to build a nearly unlimited supply of solar power satellites: metals for structure and silicon for solar cells. Developing solar power satellites and lunar mines will give us experience building large space structures and exploiting solar system rock and radiation.
Asteroids contain vast quantities of almost every sort of material; more than enough to supply Earth and a growing space community for millennia. As we know from the destruction of the dinosaurs, some asteroids come very close to Earth. These can be mined for their metals and other resources at a great profit. The experience gained will provide access to materials the Moon lacks, especially carbon and water; both essential to life.
At this point we have a robust, inexpensive transportation system moving people between Earth and orbit developed by tourism, vast quantities of energy from solar power satellites, and ample supplies of materials from the Moon and asteroids. We just need to put them in a pot, simmer lightly, and voila! Š space colonies.
Of course, even with excellent transportation, plentiful energy, and ample materials, construction of kilometer-scale space colonies will be a monumental engineering task. One that any engineer worth their salt would love to take on. And they will.
In 2004, Burt Rutan, a famous aircraft designer, said that orbital tourism will be largely affordable in 25 years. What do you think about this prediction?
If anyone else made this prediction, I would call it bunk. Coming from Burt, maybe.
Burt built SpaceShipOne, the first, and so far only, private vehicle to take a human into space. Rutan not only put a private manned vehicle into space, he did it for a few tens of millions of dollars and even made a small profit. He and Paul Allen, who financed SpaceShipOne, made ten million dollars for winning the X-Prize, got a couple million more for painting ŌVirginÕ on the tail, and then made even more money selling the technology to Richard Branson. This was a remarkable achievement.
I think it is very likely that Rutan will build practical sub-orbital tourist vehicles, and that this will lead to a profitable business. Orbital flight, however, is much more difficult. Sub-orbital vehicles just go straight up, then straight down again, at relatively low speeds. To stay in orbit, you must go over 25,000 km/hour. Otherwise you fall out of orbit and either burn up in the atmosphere or crash into the ground. Going that fast is not only difficult to do, it means that you re-enter the atmosphere at the same speed. SpaceShipOne re-enters the atmosphere very slowly, so there is little stress on the vehicle and little heat build-up. The same techniques wonÕt work for orbital flight. I donÕt think Burt has solved the problems of orbital flight and return, but he is a brilliant engineer and may come up with something that will work. I certainly hope so.
And, in the future, when can we hope the first operational space colony able to accommodate his first inhabitants?
If we really do get practical orbital tourist vehicles in 25 years, the most difficult problem (transportation from Earth to orbit) will be solved. A colony could conceivably be built within a few decades after that. That means that the younger people on this planet may see space colonies in their lifetime.
There is a way to make it happen faster. Get to work! The rock and radiation is waiting É