Mulling the unthinkable: capturing an asteroid!

Next time when your kids ask you to bring them a star from the sky, you don’t have to shrug and walk away. Tell them to wait, instead.

A group of Chinese scientists are mulling a bold idea to capture a small near-Earth asteroid, which might be a potential threat, and bring it back to Earth to exploit its resources.

“Sounds like science-fiction, but I believe it can be realized,” said Li Mingtao, a researcher at the National Space Science Center under the Chinese Academy of Sciences.

Li and his team raised the audacious idea in a contest of innovative future technologies recently held in Shenzhen, south China’s Guangdong Province, and entered the finals with another 59 projects. The contest encouraged young Chinese scientists to conceive groundbreaking technologies and trigger innovation.

The process could start with a spacecraft carrying a huge bag to wrap a small asteroid and push it back over the Earth. Then it would unfold a heat shield to reduce the velocity of the asteroid when it enters the Earth’s atmosphere, and control it to land in a no-human zone, Li explained.

Huang Wei, chief engineer at an institute of the China Academy of Space Technology, said the idea is very creative and could help promote the development of space technologies.

Li said many key technologies would have to be tackled to achieve the goal. One challenge would be finding a suitable target. The smaller an asteroid, the more difficult it is to discover. Telescopes on the ground can only find small asteroids when they come very close.

Hardest challenge

Li is working with space engineers at the Qian Xuesen Laboratory of Space Technology, under the China Aerospace Science and Technology Corporation, to draw up a plan for a satellite constellation on the heliocentric Venus-like orbit. The satellites will be used to search for and analyze near-Earth small celestial bodies with a diameter around 10 meters.

He said the hardest challenge might be the control of the asteroid after it enters the Earth’s atmosphere. They must design a heat shield, and drop the speed of the asteroid from 12.5km per second to about 140 meters per second before it touches down at a designated area.

To analyze the feasibility of the plan, Li’s team has targeted a small asteroid more than 100 million km away. It’s about 6.4 meters in diameter and weighs several hundred tons.

The asteroid’s main components are still not clear. Li calculated the proper time to launch an asteroid catcher would be 2029, and it could be brought back to Earth in 2034.

Some near-Earth asteroids are at risk of colliding with Earth. An asteroid entered the Earth’s atmosphere over Russia in February 2013, and exploded above Chelyabinsk, leaving more than 1,500 people injured and about 3,000 buildings damaged.