How to capture an asteroid and protect the home planet

It may seem more science fiction than real space exploration but NASA announced last month its plans to identify an asteroid,capture it,nudge it into our planetary region and then set it to orbit the moon. With this ambitious project,the US government aims to learn to identify asteroids heading towards Earth,change their course,and put them in a close enough orbit for astronauts to visit and space entrepreneurs to mine.

WHY AN ASTEROID CAPTURE?

Asteroids are among the oldest objects in the solar system. To get them close enough for study will allow scientists to understand what early solar system was like.

* Space scientists need prototypes to prepare for an eventual landing on Mars,yet another American space dream. An asteroid orbiting the moon,or at the second LaGrange point will be an ideal destination.

Story continues below this ad

* Orion capsule and Space Launch System,being developed by NASA for deep space exploration,will also find use.

* For planetary defence. Asteroid impacts are of increasing concern. In February,an 11,000-tonne meteorite exploded 10 km above Chelyabinsk,Russia. This explosion was 20 to 30 times more powerful than Little Boy dropped on Hiroshima. Sixteen hours later,a much bigger asteroid passed by Earth.

* For space mining by commercial space companies for the rare and valuable metals in asteroids.

Timeline

Target selection 2014

Probe launched into orbit by a solar electric propulsion system in 2017 to rendezvous with a 10-metre wide asteroid around 2019

Asteroid capture 2019

First astronaut visit to relocated rock 2021

THE CANDIDATE

Story continues below this ad

Target will be an asteroid of 500 to 1,000 tonnes. The rock needs to weigh less than 1,000 tonnes because of the limited size and nudging power of the capsule that will perform the capture.

* Asteroid needs to be on a trajectory that takes it close to the Earth and moon even without the nudge.

* Largest concentration of asteroids in our solar system is in the belt between Mars and Jupiter. But NASA is looking for an asteroid closer home.

* Consistency of captured asteroid: dried mud.

* The most desirable asteroids are the carbonaceous C-type asteroids. Carbonaceous asteroids have the most diverse composition containing a rich mixture of volatiles,complex organic molecules,dry rock,and metals.

CAPTURE MECHANISM

Story continues below this ad

The capture mechanism will include inflatable arms,a high-strength bag assembly and cinching cables.

When inflated,the arms will provide strength to hold open the 15-metre bag. The bag can accommodate a wide variety of asteroid shapes.

The captured asteroid will be moved from its original orbit to a new location near the moon or the La Grange point.

Compiled by: Priyanka Kotamraju