The blockbuster film Armageddon depicted how the Earth was faced with the threat of a direct collision with a giant asteroid from space. The disaster was averted, however, through the efforts of several government agencies that blew up the massive space rock using a nuclear device.
In case of a similar event happening in real life, the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) have both devised their own contingency plan to prevent a worldwide catastrophe.
While NASA's plan adopts elements from the film Armageddon, especially the use of satellites to set off nuclear explosions on asteroids, the ESA's plan features a gentler strategy of using a device called a kinetic impactor to blast space rocks with projectiles in order to deflect them from Earth.
The space agency's proposal, called Asteroid Impact Mission (AIM), also includes a plan to pull asteroids closer to the planet for prospecting if they are discovered to be rich in minerals.
The ESA's first target for the AIM is a pair of asteroids known as Didymos, which was spotted by different telescopes from the world.
The main body of the space rock measures at 800 meters (half a mile) in diameter, and it is orbited by a 170-meter (approx. 558 feet) moon named Didymoon. Both objects were at a location favorable for observation by Earth scientists March to June.
Meanwhile, NASA is also studying the binary system for its planned Double Asteroid Redirection Test (DART) that is expected to reach Didymoon by October 2022.
Understanding the orbit of Didymoon is vital in the planning of missions to determine the proper approach of the spacecraft as well as to identify when the asteroid moon will be covered in shadow.
The ESA has collected data on the approximate mass of the Didymos bodies. These will be examined together with earlier optical and radar data in order to refine the system's orbital period and the density of the Didymos.
Further observations of the binary system of Didymos will be continued in 2017.
"Every year, more than 1,000 new NEOs are discovered," the ESA's Gerhard Drolshagen said.
"Most of them are some tens of metres in size and have the potential to cause damage on the ground. Sooner or later, one may actually hit Earth.
Experts estimate that there are around 600,000 identified asteroids that exist in the Solar System. More than 12,000 of these space rocks are considered near-Earth objects (NEO) because of their orbit's close proximity with the Earth's path.
