As reported by SciTechDaily, this new decision method “takes into account an asteroid’s mass and momentum, its proximity to a gravitational keyhole, [the small window in which a planet’s gravity could alter an orbit of an asteroid to cause it to collide with the planet on a future orbital pass,] 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.”
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These researchers applied this new method to Apophis and Bennu, near-Earth asteroids that are the target of OSIRIS-REx, an operational NASA mission that is attempting to return a sample of Bennu’s surface to earth by 2023.
“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.”
in 2007, NASA stated the most effective way to deflect an asteroid would be to launch a nuclear bomb into space, which would knock the asteroid in question off its deadly path. However, Earth would then have to deal with any nuclear fallout from the bomb.
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The second best option was a “kinetic impactor,” which is a “spacecraft, rocket, or other projectile that, if aimed at just the right direction, with adequate speed, should collide with the asteroid, transfer some fraction of its momentum, and veer it off course.”
The problem with the kinetic impactor solution is that “properties of the asteroid, such as its mass, momentum, trajectory, and surface composition must be known ‘as precisely as possible.'”
These new mission possibilities include a basic kinetic impactor to deflect the asteroid off-course, sending a scout first to measure the asteroid before building a projectile to hit it away, and sending two scouts – one to measure and one to hit it slightly off its path before a larger projectile is launched.
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For Apophis and Bennu, such things were measured as the distances between each asteroid and their respective gravitational keyhole, as well as the “safe harbor” region, the time when the asteroid would need to be deflected to avoid disaster.
For Apophis, if it will pass through a keyhole in five years or more, there would be enough time for the two scout plan. If the keyhole passage would be two to five years, the one scout plan may be the best option. However, if it passes through its keyhole in one year or less, it may be too late according to the researchers.
This breakthrough would put at ease many, especially from scares like the “potentially hazardous” asteroid that was approaching Earth, even though it was around 3.6 million miles away.
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Adam Bankhurst is a news writer for IGN who can’t wait and is so excited he just can’t hide it. You can follow him on Twitter @AdamBankhurst and on Twitch.
