After the dinosaur incident, humans are extremely cautious when it comes to an asteroid and our planet. Okay, probably not because of that, but asteroids do pose a major threat to life if they happen to strike the Earth. Ever wondered what should be the plan of action in such a scenario? So, has NASA.
The International Academy of Astronautics will be holding the 2019 Planetary Defense Conference next week, where one of the events is the “asteroid impact exercise” where a fictional but realistic simulation of an asteroid about to crash into Earth will be tested. The scenario has been designed by NASA’s Jet Propulsion Laboratory’s Centre for NEO Studies (CNEOS). The various approaches discussed could eventually act as a solution of saving ourselves from near-Earth Objects (NEO), which are asteroids or comets that come within 50 million kilometres of the Earth’s orbit.
With an estimated 1,000 near-Earth asteroids wider than a kilometre across, even the smallest probability of a collision needs serious attention.
The simulation begins with astronomers ‘discovering’ a potentially hazardous NEO called “2019 PDC”. After tracking it for a few months, they conclude that it has a 1% chance of impact with Earth, in 2027. That is enough likeliness to put humanity at a risk, and a lot of preparation will be needed to actually control an event of this stature.
Agencies like NASA’s Planetary Defense Coordination Office (PDCO), the European Space Agency’s Space Situational Awareness-NEO Segment and the International Asteroid Warning Network (IAWN) will all be a part to the final act. This will be the sixth time NASA participates in a NEO impact exercise, and has learned a few key things. One of them includes what information disaster managers are looking for, which understandably has little to do with the specifications of the asteroid. “What emergency managers want to know is when, where and how an asteroid would impact, and the type and extent of damage that could occur,” said Leviticus Lewis from the Federal Emergency Management Agency (FEMA).
So how do they plan on keeping us safe in case of such an incident? The approach involves smashing into an asteroid or its moon to alter its course trajectory. The first mission is scheduled for June 2021, as a part of NASA’s Double Asteroid Redirection Test (DART). In collaboration with SpaceX, one of the Falcon 9 rockets will be fired in the direction of asteroid Didymos, which will pass by Earth in October 2022 along with its tiny satellite called the “Didymoon”. A system like this where two asteroids are orbiting together is termed as a binary asteroid. While Didymos faces no threat to our planet, it will be a good opportunity to check if the DART spacecraft can actually change the orbit through a technique called “kinetic deflection”. If things go as planned, the 500kg DART will crash into the asteroid’s moon at about 6km/s resulting in a change in orbital velocity, and thus the trajectory of Didymos.
As cool as this mission sounds, it is still pretty ambitious and the success rate might not be very high. The European Space Agency “Hera” will conduct a follow-up mission to check the changes and if the impactor worked. From a distance of around 200 metres, it will deploy lasers, a star-tracker and a thermal infrared camera to check the success of the “asteroid redirect”. We will have to live in a fair bit of suspense though, as Hera’s satellite will reach the asteroid in 2026, some three years after departing from Earth.
