Researchers at Massachusetts Institute of Technology (MIT)have developed a computer program that will help to decide the best mission for deflecting a catastrophic asteroid collision or in simple words an incoming asteroid towards earth. The name of the program is “decision map”.
According to a report, there are as many as two or three new asteroids discovered every night. These are called ‘Near Earth Objects’. It is inevitable that one of these asteroids will eventually end drifting into a collision course with Earth.
“People have mostly considered strategies of last-minute deflection when the asteroid has already passed through a keyhole and is heading toward a collision with Earth,” says Sung Wook Paek, lead author of the study and a former graduate student in MIT’s Department of Aeronautics and Astronautics. “I’m interested in preventing keyhole passage well before Earth impact. It’s like a preemptive strike, with less mess” , reported MIT news
The “decision map” would take into account an asteroid’s mass and momentum, its proximity to a gravitational keyhole, and the amount of warning time that scientists have of an impending collision — all of which have degrees of uncertainty, which the researchers also factor in to identify the most successful mission for a given asteroid.
A gravitational keyhole is a tiny region of space where a planet’s gravity would alter the orbit of a passing asteroid such that the asteroid would collide with that planet on a given future orbital pass. If asteroids can be detected before reaching this point, they can be redirected with minor changes in course—sometimes as little as a few centimeters per second.
The researchers applied their method to Apophis and Bennu, the near-Earth asteroids, the latter of which is the target of OSIRIS-REx, an operational NASA mission that plans to return a sample of Bennu’s surface material to Earth in 2023.
REXIS, an instrument designed and built by students at MIT, is also part of this mission and its task is to characterise the abundance of chemical elements at the surface.
The most effective method till now proposed by NASA in 2007 to U.S. Congress is to send a nuclear missile to detonate on the asteroid surface.
This option would also leave a substantial amount of nuclear debris in orbit around the planet, which would eventually reenter the atmosphere and cause a number of complications, making it the most controversial and least likely.
The researchers tested their simulation on Apophis and Bennu, two of only a handful of asteroids for which the locations of their gravitational keyholes with respect to Earth are known.
- Using a “kinetic impactor,” or a projectile sent into space to attempt to divert the asteroid.
- Sending a “scout” first to gain specific measurements of the asteroid so a more accurate projectile can be used.
- Sending two scouts: one to measure the asteroid and the other to push it slightly off course before a large projectile can be used to ensure it misses Earth, like a game of cosmic billiards.
They say time is the most important factor in determining which method would be best.
If a planet-killer asteroid was more than five years away from entering Earth’s gravitational keyhole, sending two scouts and a projectile would be the way to go, the MIT researchers concluded. If we have between two and five years, sending a single scout and a projectile is the safer option. With one year or less, Paek said it may be too late to do anything at all.
The research paper is appearing this month in the journal Acta Astronautica.