While the Planetary Resources only recently announced their intention to engage in the production of platinum and constantly rising in price of rare earth elements on asteroids, NASA back in 1975 in conjunction with Stanford University (USA) studied theoretically the problem.

The Agency concluded that for the cost-effective development asteroid material it should be delivered to low earth or Preluna orbit, where the processing will take over this space colony comprising not less than 10 thousand people. Stay settlements in space experts assessed as unlimited. Conceptual development of the project was performed at a high level and has not lost its relevance today.

In this regard, NASA conducted a theoretical study of the problem of unlimited duration of stay of a spacecraft with tens of thousands of people on Board in the near-earth or Preluna space. The aim was to prepare for the creation of large orbital stations involved including processing asteroid material. Another, not less important task could become colonization of the moon or other areas of the Solar system.

Sounds like the SF story, but in the mid-1970s, NASA really seriously address the problem. And we would not return to this subject today, if not increased in recent interest to the then report. Strangely enough, no major studies on this topic is still there. And, it seems that the authors are written in the 70 works very deep insight into the task, at least they managed to avoid many errors developers "Biosphere-2".

Let's remind: in the West in the 1990s began a series of experiments such as "Biosphere 2, have had a number of smaller Soviet counterparts like the BIOS-3. All of them later "Mars-500", were designed to detect various medical, psychological and technical aspects of a long stay of a person in an unnatural environment resembling the one that is formed during long space flights. It was found that a number of aspects of life-support of the person in space in the tested as simply cannot function normally for a long time in a closed environment, without external feed.

In 1975, NASA had hoped to plan the main parameters of the ship to colonize the middle of the space, that is about the external recharge it was not. In the course of research the specialists of the Department found a number of non-trivial things. First, it was already clear that in weightlessness all 10 thousand inhabitants forever to keep the impossible. It was therefore decided to make the station rotary - to create pseudographical. Secondly, securing the gas balance was considered as a problem №1, and she was given special attention, with a number of unusual findings. Finally, the space required to accommodate 10 thousand colonists was planned much more generous than in later experiments, and did it not to the latitude of the American soul, but for very practical reasons.

The materials were chosen, of course, is simple: aluminum alloy for external designs, fabric and plastics for interiors. However, in the latter respect, it was recommended to undertake research on creation of such polymers, which would appear as a "natural materials - stone and wood. Why aluminum? The composition of lunar rocks, known already, talked about the presence on the moon, large quantities of anorthosite - mineral containing aluminum. In order not to transport most of the materials from the Earth, space settlement was proposed to place in the point L5, very close to the moon. And extracted it anorthosite be processed directly in the construction of the colony, after the construction of the first production module.

The material was dictated, and many special design features: one large field was rejected because a sealed volume in this case would be disproportionately large. And it was sealed part of the colony would require walls greatest strength and mass. The weight savings are also made to reduce the requirements to the atmosphere. It turned out that for the station with a large internal volume of the atmosphere's mass will be a huge part of the total weight up to 88 thousand tons based on the available time of medical data was recommended to reduce atmospheric pressure of 0.5 ATM, increasing the concentration of oxygen, carbon dioxide and a low - nitrogen. In this case it was needed just 44 tons of atmospheres, and more importantly, decreased strength requirements sealed compartments, which allowed to reduce the weight of the structure of the colony to 150 thousand T. In this version actually the station would weigh less than 200 thousand t, that gives to 20 tons of weight on one person. For comparison it should be noted that the same ISS has about 417 tons of weight on 6 astronauts, nearly 70 tons of pulp per person. One of the main reasons of such weight perfection project 1975, in addition to economies of scale, let's call the maintenance of the ISS pressure of 1 ATM, forcing to have a solid and heavy shell.

Already then it was clear that, in addition to kidney stones and known difficulties in women, gravity causes a number of diseases, of which muscular dystrophy is not the greatest evil. Hence, the ship should rotate. But only by its edges will be similar gravity, and the Central region will remain without pseudographical. Therefore, spherical and cylindrical shape of a ship is unacceptable: too much space cannot be used fully. Important: sealed spherical ship must have a huge area of heavy and solid walls, able to withstand the pressure of the atmosphere. The ideal shape of a ship must be torus (or dumbbell), with two big spherical modules, connected by a thin crosspiece. When this was discovered unexpected problem: the tor should be very, very large, with a diameter of 1.8 km (10 thousand inhabitants). The dumbbell, however, would be even more so the choice was Torah.

Space colony in the period of construction (top) and after sealing and settlement (bottom). Great importance attached psychological comfort: there's even a decorative water and sunlight through the transparent roof with aluminum blinds.
Space colony in the period of construction (top) and after sealing and settlement (bottom). Great importance attached psychological comfort: there's even a decorative water and sunlight through the transparent roof with aluminum blinds.

It flowed from a serious requirements to inner space, founded by the developers of the concept of the project: according to the research team, to ensure long-term (years and more) psychological stability colonist was required not less than 50 sq only housing (!) and on 15-17 sq. m sealed providing areas (energy sector and so on). Total area sealed volume station was estimated at 670 thousand square meters That is interesting, given the insistent recommendation to place hydroponic plants "integrated", introducing them in the overall landscape separate "spots". It was not only in the care of the psyche of the crew: with unlimited time on orbit failure of certain systems of ventilation was seen as likely. So, the natural replenishment of oxygen and evacuation of carbon dioxide became mandatory for sustainable livelihoods.

The closest attention was paid to protection from space radiation. According to the authors, the dose of 0.5 REM per year is the maximum for a long stay of people and electronics in orbit. Therefore, active protection option will be rejected: the magnets, creating an artificial magnetic field, will eat too much energy. Magnetic field to protect against particles with energies of 0.5 GeV will require equipment weighing about 10 thousand tons And still dose will exceed 20 REM per year per person. Need the same power protection will be very heavy and energy-intensive.

So, oddly enough, was selected passive protection, with the required weight of 4.5 tons per sq. m of the outer walls of the Torah. However, in applying to the entire colony it means to 9.9 million tons, which excluded delivery passive shield such power from the Earth. However, because the colony was aimed at the development of asteroids, from the same was supposed to deliver and material shield. In this case, the shield would be placed around the Torah without giving rotation, which, in turn, meant that the gap in 1-2 m rotating between Thor and motionless protection.

Just note: the dose of 0.5 REM per year, adopted by developers, is very low. Even modern transistor electronics can work with dozens of times greater annual dose of radiation. According to current concepts and norms, cosmonaut (or worker NPP) a year without harm can get up to 5 REM, which is ten times more. The authors themselves point out that future research can raise the acceptable dose of radiation, and this does not only reduce the weight of protection, but also will be able to return the relevance of its active option. Especially effective in this case they call ring-shaped channels (on the perimeter of the Torah colony) with plasma held magnets and supported them in motion, to generate a magnetic field that will repel particles with energies up to 1 GeV. The developers also noted that if the space colony of this kind would need to travel at significant distances and high velocity, active protection would be the only possible solution: the barrier of the asteroid material, even calculated at the annual exposure of astronauts 5 REM, weighed would 990 thousand tons - five times greater than the colony. So, to move it would be almost impossible - at least economically.

By the way, about the economy. The total value of such a large colony was to be $190 billion in the prices of 1975. Therefore the payback period was achieved only after 28 years of continuous operation. And then there was a profit. In today's money this is about equal to the U.S. annual military budget. However, the authors of the study suggested to build the station in about a decade. So expenses on it in case of implementation in our time would be somewhere one-tenth of the military expenditure of the United States. Of course, it is doubtful that some state in the next century will spend a tenth of its military budget for the space. Therefore, for NASA's concept of a space colony remained concept.

Of course, plans Planetary Resources, at least at first, will not be as large. However, without generating plants, will inevitably require human presence at least for repair and adjustment of equipment, ultimately not do. The reliability of robotic technology for extraterrestrial planetary bodies is well-known, it is enough to recall the story of the " Habusu". But even if the plant Planetary Resources will be much less project 1975, the main decisions for such colonies in the whole, to be very close.

In short, despite the antiquity of the project, it can become an important resource for the new candidate for the space of wealth.

Based on the materials of the project Space Settlements: A Design Study.