In our Solar System, asteroids are found mostly in a belt located between the orbits of Mars and Jupiter, at a distance between 2 and 4 times the Earth-Sun distance. Although there are others with steep orbits that cross the path of the Earth: they are the Near Earth Objects , Near Earth Objects or NEOs . It is difficult to estimate their number, because in addition to those that return from time to time there are those that approach the Sun for the first time. Of the asteroids whose orbital movement brings them relatively close to the Earth, it is estimated that there are about 1,000 , although only we have discovered a fourth part. The ones we have found range in size from 32 km to less than 100 m (the two largest known are 1036 Ganymede, at 32 km, and 433 Eros, at 23 km). The reason we don’t know of smaller asteroids is not because they don’t exist but because they are hard to find.
Of all these, the ones that interest us are those that receive the name of EROs, Easily Recoverable Objects . Defined as such in 2013, this chosen subgroup of NEOs currently comprises just over a dozen asteroids. They are so defined because they are potentially exploitable with our current technology. In other words, if we wanted to (and had the money) we could move them from their orbit to a more accessible one and lower their speed to a more acceptable less than 1,700 km/h . An example is the asteroid 16 Psyche, with a mass of 17 trillion kilos. Why is it so interesting? Because it is essentially composed of iron and nickel, so it could supply our planet with these elements for several million years.
Of course, to ensure a continuous flow of raw materials , the most appropriate thing is to install mining bases in the places where these asteroids are found. Doing so is going to require all of our inventiveness.
The problems of a mining base in space
The biggest problem with this type of facility is the supply of water and oxygen . Some have proposed the capture of other types of objects, comets. We know that they are composed mainly of ice, frozen carbon monoxide and dioxide, methane and ammonia, to which must be added other volatile elements such as oxygen, sulfur and nitrogen and substances such as silicates, polycyclic aromatic hydrocarbons, amorphous carbon, iron, magnesium, sodium and metallic sulfates such as pyrite, then are also good candidates for mining. Luckily , the abundance of ice in comets largely ensures the survival of a mining settlement: from it you get the water to live and the oxygen to breathe . However, such a base has the important handicap of obtaining energy. In fact, the most limiting factor for colony size in the outer regions of any star system is access to a continuous and stable source of energy. The only viable option is for it to be provided by a nuclear fusion reactor – assuming we manage to build one in the next 40 years: a medium-sized comet contains on the order of 50 to 100,000 tons of deuterium, the best fuel for fusion.
A separate issue is life in these settlements. Those who were there would have to know a little about everything: the practical application of the old adage of ‘apprentice in much master of nothing’, because they could not be subject to the arrival of help from, possibly, the Mars base. Peter Hyams’s film, starring Sean Conery, Zero Atmosphere (1981) is the one that has best recreated what life could be like in a similar environment. Defined as a space western – we could say that it is a science-fiction remake of Alone in the face of danger – it shows life in a mining colony on Io , the volcanic moon of Jupiter. The production design reflected a dark, claustrophobic and isolated environment, which is exactly what one will find in those latitudes. Of course, Hyams decided to give a dark tone to an industrial future where large corporations seek maximum profit at the expense of their workers , who are expendable. There are things that do not change, not even in space.
Life in that environment, in which the population would not be very extensive, would have a major problem: the feeling of loneliness that will undoubtedly overwhelm the colonist will be the main battle horse in this type of space exploitation. We can imagine a simile with a condition that now exists on Earth: life in the Australian outback, the outback – a loose term for something that is out and back . In this case the fundamental difference is the climatic one: from the cold of space to 40 degrees in the shade. But the feeling of loneliness, of not having anything else to do after work, will be very similar. According to those who live there, like the Spanish electrician Manuel De La Vara, the hardest thing is “not having anyone, being alone and having nothing to do once you finish the job” . The psychological risks of living in such an extreme environment are enormous and that is why there are organizations like Frontier Services , linked to the Presbyterian Church, which has been traveling through the outback for more than a century assisting those who succumb to loneliness and isolation. How to solve this problem in space is another matter.
Of course, all this happens because we can move regularly through our near space, and that depends on whether we are able to find the Holy Grail of space adventure: an economically affordable propulsion method . We must find a viable alternative to current liquid fuels, or discover something that is more efficient than what we already have, since it is unfeasible to travel to the stars in a vehicle in which 98% of its mass is fuel…
There are those who say, and they are not without reason, that all this colonizing of the solar system is a waste of time and money, and they remember the words that one of the pioneers of radio astronomy, Edward Purcell, said in 1960: “ All this history from traveling the universe clad in spacesuits must go back to where it came from: the cereal boxes .” Interestingly, one of the most passionate defenses that we should ride among the stars is that of Jeffrey Sinclair, commander of the Babylon 5 station in the sci-fi series of the same name: “Ask 10 different scientists about the environment, the control of population, genetics… and you’ll get 10 different answers. But there’s one thing every scientist on the planet agrees on, whether it’s 100, 1,000, or a million years from now. Eventually the Sun will cool down and go out. and when that happens it will not only be the end of us, but the end of Marilyn Monroe, Lao-Tzu, Einstein, Nelson Mandela, Buddy Holly, Aristophanes…, and all of this will have been for nothing if we don’t reach the stars .”
Lewis, J. S. (1997) Mining the sky, Basic Books
Sivolella, D. (2019) Space Mining and Manufacturing, Springer