Asteroids are made up of the same materials as Earth, and other planets, but in different quantities. Our planet’s gravitational pull has resulted in most of its iron-loving materials being sucked to the core billions of years ago. This left the crust almost completely depleted of these elements. Without a gravitational pull, the metals on asteroids have remained close to the surface. Over millions of years, asteroid impacts deposited metals on the Earth’s crust. These have since been extracted in large quantities, and the resources are once again running out.
Space corporations are currently looking into the possibility of asteroid mining which would consist of taking metals, and other useful materials, from the surface of the asteroids. These extractions can be used in space, or taken back to Earth, and include: water and oxygen to sustain astronauts while in space, gold and palladium to send back to Earth, iron and titanium for space construction and hydrogen and ammonia as rocket propellant. The asteroids that are closest to our planet, would be the first targets. Investors believe that once asteroid mining has been perfected, it will become a trillion dollar industry.
There are three types of asteroids that are being considered for mining:
C- type – These asteroids have an abundance of water, and would be ideal places to refill astronaut supplies during space exploration. The option of stopping for water would greatly reduce mission costs. In addition, they also have organic carbon which would allow food growth.
S-Type – The surface of these asteroids is full of numerous metals, such as cobalt, nickel, gold and platinum.
M-Type – A source of up to ten times the amount of metal on S-type Asteroids.
Scientists have come up with three ways in which asteroid mining can be performed: mining the asteroid and bring the raw materials back to Earth, processing the materials before leaving to produce propellant to fuel the return trip or transporting the asteroid to a safe orbit around the moon, or our planet, where it would then be studied and mined.
A leader in space exploration, NASA has been researching asteroid mining for many years. They have already launched OSIRIS-REx on September 8, 2016, to facilitate the study of asteroid 101955 Bennu. The spacecraft will return to Earth with a sample of its surface in 2023, so that it can be studied in detail. If OSIRIS-REx is successful it will be the first mission that has brought an asteroid sample back to Earth.
NASA is also currently working on a mission called the Asteroid Redirect Mission (ARM). The aim of this project is for a spacecraft to use robotic arms and anchoring grippers which it will be fitted with, to retrieve a 4 metre boulder from a near-earth asteroid. The boulder will then be transported to a stable lunar orbit for analysis by robotic probes and future missions. ARM will be launched in December 2020.