NASA will be able to colonise space by creating “petrol stations” around the solar system using asteroids, a leading Cambridge professor revealed during a radio broadcast.
The idea of mining the planets, Moon, asteroids, and comets for their valuable mineral resources is not new. Science fiction writers began weaving tales of space mines, worked by crusty, usually antisocial old prospectors, in the 1930s.
Asteroids are rocky, airless worlds that orbit our Sun, but are too small to be called planets. Tens of thousands of these minor planets are gathered in the main asteroid belt, a vast doughnut-shaped ring between the orbits of Mars and Jupiter. Asteroids that pass close to Earth are called Near-Earth Objects, or NEOs. There are millions of them flying around space and their collisions – known as impact events – have played a significant role in shaping many planets.
The asteroids are composed of iron, nickel, platinum, and other metals, as well as sulphur, aluminium oxide, carbon compounds, and other minerals. Many asteroids also contain smaller amounts of volatile's, including hydrogen, oxygen, and water.
Carolin Crawford, a UK astrophysicist researcher based at the University of Cambridge has an answer to the problem.
She envisages a future where space agencies like NASA use asteroids to extract vital materials instead of digging deeper into the Earth.
The 55-year-old explained her theory during a BBC Radio 4 “In Our Time” broadcast on asteroids.
She said in 2005: “It is a very interesting possibility when you look at our mineral resources on Earth, they haven’t run out yet, but give them a couple of centuries and they will be in short supply.
“You could set up a mining camp on one of these asteroids and get billions of tonnes of high-grade metal and there is also water to sustain the camp.
“Or we could tow an asteroid to orbit around Earth as a little petrol station for future missions.”
A race is on to mine billions of dollars in resources from the solar system’s asteroids, fuelling our future among the stars. Asteroid mining company Planetary Resources estimates that the 16,000 rocks near Earth could hold two trillion metric tons of water. A widely cited Goldman Sachs report says that a football field-sized asteroid could contain “$25 billion to $50 billion worth of platinum.”
Fore example the smallest known M-type asteroid—Amun 3554 is about 1.2 miles across and has a mass of about 30 billion tons. To put this large tonnage in perspective, imagine that the raw materials from the mining operation are loaded into a fleet of space shuttles like those that were part of NASA's fleet. The cargo bay of a typical shuttle holds about twenty-five tons. It would take four hundred shuttles, therefore, to haul ten thousand tons of asteroidal material; and it would take 1.2 billion shuttles to carry all of the materials mined from Amun 3554.
Regarding the materials themselves, Amun's total tonnage breaks down into many different metals. The most abundant of these are iron and nickel, which alone would have a market value of about $8 trillion. Supplies of another metal, cobalt, on Amun would be worth perhaps $6 trillion. Then there are rarer metals such as platinum, iridium, osmium, and palladium, which together would add another $6 trillion to the investors' profits. The nonmetals, including carbon, nitrogen, sulphur, phosphorus, oxygen, hydrogen, and gallium, would be worth at least $2 trillion.
Ms Crawford even took the idea one step further, detailing how the theory could help further exploration of space.
She added: “So it is a supply of mineral resources and we are going to need these if we want to colonise the solar system.
The recent discovery of an asteroid wrapped in a layer of water ice has revived the possibility that some space rocks would be great potential pit stops as well as semi-permanent mining camps.
If a space destination has water, that means astronauts travelling there could potentially use it for drinking and washing. But much more importantly, some may offer, for example, a ready source of rocket propellant — made from separating water into hydrogen and oxygen, that are expensive to bring from Earth.
“If we are building large space structures and need lots of rocket fuel, it does not make sense to launch it up to space.
To extract the water, astronauts or robots would collect samples of the dirt or rock and grind them up into a powder. Then, the material would need to be heated ? possibly with a microwave to drive off the water so it can be collected. Finally, the water must be cleaned so that few impurities are left. To get to a usable fuel, water must be broken down through a process called electrolysis, converting the H2O in to Hydrogen and Oxygen. Electrolysis units are fairly standard pieces of equipment that are often used in life-support systems.
Once these steps are taken and a sample of water is available, actually turning it into rocket fuel isn't that hard.
An asteroids relatively small mass means their gravitational field is weak, so in this respect, at least, they are much easier than larger bodies such as the moon to land on and leave, making asteroids perfect refuelling stations.
“Why not just use what is already up there? It’s easily extracted from small objects that don’t have a lot of gravity.
“These asteroids are not just iron and nickel but they also have platinum – which we use as a catalyst converter.
“All these elements are in the core of the Earth where we cannot get to.
“It is easier to develop a system to go to the asteroid, than penetrating to the great depths of the Earth’s core.”
Asteroids could be put to continued use after they have been stripped of they're host minerals as permanent. human habitats. Hollowed asteroids used as habitats are standard fare in science fiction. Often such habitats are made from a nickel-iron asteroid using heat and internal pressure to expand it into a thin spherical shell. Frequently heat is supplied by focused solar radiation or by nuclear devices.
A sufficiently large asteroid would also provide good protection against interstellar radiation and micro-meteorites.
Spinning the asteroid has been the traditional way to obtain artificial gravity. More recently a number of people have recognized that spinning a structure inside a hollowed out cavity of the asteroid is a lot easier and maintains the low gravity environment of the asteroid on the surface, which has manufacturing advantages.