Not so long ago, Planetary Resources announced its plans to start production of rare earth elements on meteorites and faced a number of challenges in realizing this goal. But it turns out, back in 1975 NASA, in conjunction with Stanford University (USA) to address this problem and created a working model …
The Agency has concluded that the cost-effective development of the asteroid material it must be delivered into Earth orbit or prilunnuyu where processing will take on a real space colony of at least 10 thousand people. The residence time of the settlement in space experts have estimated as unlimited. Conceptual study of the project was completed to a high standard and has not lost relevance today.
In this regard, NASA conducted a theoretical study of the problem of unlimited residence time of the spacecraft with tens of thousands of people on board in the near-Earth space or prilunnom. The aim was to prepare for the creation of large space stations, including dealing with the processing of asteroid material. Another equally important task would be colonization of the Moon or other regions of the solar system.
The American project (above) is different from the ideas of Tsiolkovsky and "Stars Katz" (bottom) in the main reflector of sunlight, concentrating it on a photocell station when they are in the shade and covering the inner surface of the torus. (Fig. NASA, «TM").
Sounds like a sci-fi story, but in the mid-1970s, NASA and indeed of tackling the problem. And we would not have to return to this subject today, if not intensified in the recent interest in the then report. Oddly enough, no other major research on this topic is still no. And, it seems, the authors wrote in the 70's work is deeply penetrated into the task, at least they managed to avoid many mistakes developers "Biosphere 2".
We recall that in the West in the 1990s began a series of experiments similar to "Biosphere 2", which had a number of smaller-scale Soviet counterparts like the same BIOS-3. All of them, like the later "Mars-500", were designed to identify a variety of medical, psychological and technical aspects of the long stay of the person in an unnatural environment, reminiscent of the one that develops during long space flights. It turned out that a number of aspects of human life support in space in the form of a tried-simply can not function properly for a long time in a closed environment, without having fed from the outside.
In 1975, NASA had hoped to plan the basic parameters of the ship for the colonization of the near space, that is, external financing were not discussed. In the study, management experts have found some non-trivial things. First, it was already clear that the zero-gravity all 10 thousand inhabitants can not hold forever. Therefore, it was decided to make the station a rotating — to create a pseudo-gravity. Second, the provision of gas balance was seen as a problem number one, and she has been given special attention, with a number of unusual findings. Finally, the space needed to accommodate 10 thousand colonists had been planned much more generous than in later experiments, and did not do it on the breadth of the American soul, and for very practical reasons.
The materials were chosen, of course, simple: aluminum alloy exterior design, fabric and plastic materials for interior decoration. However, for the latter were encouraged to undertake studies on the establishment of such polymers, which would appear as a "natural materials" — stone and wood. Why aluminum? The composition of lunar rocks, known even then, spoke of the presence of large reserves on the moon anorthosite — a mineral that contains aluminum. Not to carry greater rigor of the material from the Earth, the space settlement offer to place at L5, very close to the Moon. A mined her anorthosite process directly in the target colony, after the construction of the first production module.
The material is dictated many of the design: one large area immediately eliminated because a sealed volume in this case would have been disproportionate. And it was sealed part of the colony would require walls greatest strength and mass. Weight savings are also made to reduce the requirements to the atmosphere. It was found that for a station with a large internal volume of the mass of the atmosphere will be a huge part of the total weight — up to 88 tonnes, with reliance on the then-available medical data, it was recommended to reduce the air pressure to 0.5 bar, increasing the oxygen, carbon dioxide and lowering — nitrogen. In this case, the required total of 44 tons of atmosphere, and most importantly — to reduce the strength requirements for sealed compartments, allowing to reduce the mass of the structure of the colony to 150 thousand tons in this embodiment, the station itself would weigh less than 200 tonnes, which is worth 20 tons of weight for one person. For comparison, it should be noted that the same ISS has about 417 tons of weight by 6 astronauts, nearly 70 tons of weight on the person. One of the main reasons for the weight of perfection of the project in 1975, except for economies of scale, called the maintenance of the ISS pressure of 1 atm, which forces have a solid and heavy shell.
Even then it was clear that, in addition to kidney stones and certain difficulties in women, weightlessness causes a number of diseases, including muscular dystrophy is not the greatest evil. So, the ship should rotate. But only at its edges will be similar gravity, the central area is left without the pseudo. Therefore, spherical and cylindrical shaped craft unacceptable: too much space can not be used to the full. The main thing is sealed spherical ship must have a large area of strong and heavy walls that can withstand the pressure of the atmosphere. The ideal form of the ship must be a torus (or dumbbell), with two large spherical modules connected by a thin bridge. This came to light when an unexpected problem: a torus must be very, very large, with a diameter of up to 1.8 km (for 10 thousand inhabitants). Dumbbell, however, would be even greater, so the choice was stopped on the torus.
Space colony during construction (top) and after sealing and settlement (bottom). A huge emphasis is placed on the psychological comfort: There's even a decorative ponds and sunlight through the transparent roof with aluminum blinds.
This stemmed from the serious to the interior of the requirements laid by the developers of the concept of the project: According to the research team, to ensure the long-term (years or more) psychological stability colonist of no less than 50 square meters. m only housing (!) and another 15-17 square meters. m providing sealed areas (power unit, etc.). Total area of the pressurized volume of the station was estimated at 670 thousand square meters. m What is interesting, let's insistent recommendation to place hydroponic plants are "integrated", introducing them into the overall landscape of the individual "spots". It was not only in the care of the psyche of the crew: for an unlimited time in orbit failure of various ventilation systems was seen as quite probable. So, the natural replenishment of oxygen and carbon dioxide evacuation became mandatory for sustainable livelihoods.
Most attention was paid to protection from cosmic radiation. According to the authors, the dose of 0.5 rem per year is the maximum allowed for an extended stay of people and electronics in orbit. Therefore the active version of the defense will have to reject: the magnets, which create artificial magnetic field, will eat too much energy. The magnetic field for protection from particles with energies up to 0.5 GeV will require equipment weighing about 10 tons and is still at the same radiation dose exceeds 20 rem per year per person. The required power for the same protection will be very heavy and energy intensive.
So, oddly enough, was chosen passive protection to the required weight of 4.5 tons per square meter. m outer wall of the torus. However, when applied to the entire colony, this means 9.9 million tonnes, which excluded the passive shield delivery of such power from the Earth. However, since the colony aim at the development of the asteroid, there is supposed to deliver and the material of the shield. This would itself shield placed around the torus without imparting rotation, which, in turn, meant that the gap between 1-2 m and a stationary rotating torus protection.
Just note: a dose of 0.5 rem per year adopted by the developers is very low. Even the modern transistor electronics can operate at tens of times higher annual dose of radiation. According to current concepts and standards, the astronaut (and the employee NPP) a year without harm can receive up to 5 rem, which is more than ten times. The authors themselves note that future research can raise the acceptable radiation dose, and this will not only reduce the weight of protection, but also to be able to return to the relevance of its active version. Especially effective in this case they are referred to as annular channels (the perimeter of the torus colonies) with the plasma, and the permanent magnets supported by them in movement, for generating a magnetic field which will repel particles with energies up to 1 GeV. The developers also noted that if such a space colony had to make a trip to the significant distances and at higher speeds, the active protection would be the only possible way: after the barrier of asteroid material, even for up to an annual exposure of astronauts to 5 rem would weigh 990 tonnes — more than five times the colony. So, move it would be almost impossible — at least economically.
By the way, about the economy. The total cost of this massive colony was to be $ 190 billion in 1975 prices. Therefore, the payback period was achieved only after 28 years of continuous operation. Only later was planned profit. In today's money is about equal to the annual U.S. military budget. However, the study authors suggested to construct the station in about a decade. So that the cost of implementing it in the case of our time would have amounted to around one-tenth of U.S. military spending. Of course, it is doubtful that any state in the next century will spend a tenth of its military budget for space. Therefore, for the NASA space colony concept has remained a concept.
Of course plans Planetary Resources, at least the first time will not be as large scale. However, without the establishment of factories, inevitably requiring human presence at least for the repair and adjustment of the equipment is ultimately not enough. The reliability of robotic technology for extraterrestrial planetary bodies is well known, it is enough to recall the story of the "Hayabusa". But even if the plant Planetary Resources will be much less than the project in 1975, the main solutions to this kind of colony as a whole seem to be very close.
In short, despite the antiquity of the project, it could become an essential tool for a new contender for the space of wealth.