Space mining is an idea that began taking hold at the turn of the century, and 10 years ago, it was passionately discussed. Many argued that space mining could revolutionise the commercial space economy by employing robots and private astronauts to explore and mine near-Earth asteroids (NEAs) for precious metals and even rare earth metals. Since then, however, there has been little noticeable progress. This idea again made its way into public discourse this weekend as an NEA — called 4660 Nereus — passed the Earth. Scientists believe the egg-shaped asteroid with a diameter of 330m holds precious metals worth an estimated $5 billion (roughly Rs. 3.78 lakh crore).

Nereus at no point came dangerously close to Earth. At its closest, it was 3.9 million kilometres away — about 10 times the distance between the Earth and the Moon. Scientists say it would again pass by Earth in 39 years from now — and at that time it could be possible to launch “space miners” to see how we can use those precious metal deposits on this asteroid.

According to a report by Asterank, which has a scientific and economic database of over 6 lakh asteroids, Nereus is composed of $4.71 billion (roughly Rs. 3.56 lakh crores) worth of iron, cobalt, and nickel. But further research after the recent flyby will throw more light on its characteristics.

Franck Marchis, chief science officer for Unistellar, which makes digital telescopes, told Forbes that Nereus will be flying only 1.2 million kilometres from the Earth in February 2060, when “space miners” could attempt to land on it. “As a regular guest of our planet, Nereus could play a significant role in the future of space exploration, providing key resources,” said Marchis.

Another topic that worth noting is how Nereus’ recurrent flybys affect the Earth’s safety. The asteroid has been classified as “potentially hazardous.” Even when the asteroid passes the Earth in 2060, it will be five times the distance between the Earth and the Moon. Objects that come close to Earth and are large enough to cause substantial damage are classified as “possibly hazardous.” This suggests the danger that objects like Nereus can cause in future since they cross Earth’s orbit at some point.