Two NCSU Researchers Believe They've Discovered A Realistic Approach To Stopping A Deadly Asteroid Strike

RALEIGH—Growing fears of an earth-bound killer asteroid has abounded for years, but as technology has advanced, so has astronomers’ knowledge of how many potential threats could loom in our future, in which an asteroid hurtling in from space could actually strike the Earth causing cataclysmic destruction.


Such scenarios have also played out on the big screen where an impending asteroid strike incites helpless panic. Some such films play heavily on science fiction while others offer potential considered possible among scientist.


In some storylines, the heroes saves the Earth from impending doom such as in the blockbuster movie, Armageddon. In this 1998 film, an oil-drilling team ventures into space, rendezvous with the asteroid with hopes of blowing it up in dramatic Hollywood fashion with a nuclear weapon. 


While using a large explosion has been suggested, inherent risks are associated on both a political and scientific nature. Not only would there be significant ramifications for one country to take it upon itself to use nuclear weapon technology to conduct such a feat, blowing up an enormous asteroid would only create many smaller, yet still dangerous pieces of debris. Other possibilities have been to attach rockets to “steer” an ominous asteroid onto a slightly different trajectory that would miss the Earth. Other seemingly great ideas would likely be more suited for a sci-fi movie rather than a realistic solution.


Enter David French. In a recent study conducted at North Carolina State University (NCSU), a plausible idea has developed that may save the world from annihilation or at spare a particular geographic region from unspeakable damage.


French, who is a doctoral candidate in aerospace engineering at NCSU has determined a way to divert asteroids and other threatening celestial objects from impacting Earth. Instead of using explosives, rockets or other fanciful ideas, French has determined that using a tether and ballast could, as French explains, “change the object’s center of mass, effectively changing the object’s orbit and allowing it to pass by the Earth, rather than impacting it.”


While asteroids may not seem to be that great a threat, NASA’s Near Earth Object Program has identified more than 1,000 “potentially hazardous asteroids” and more are being discovered all the time. According to French, while the vast majority of these objects do not seem to pose an immediate threat, there are risks of trajectory changes effected by gravitational pull, solar wind push or other causes that could alter the path, bringing a large asteroid very close to the Earth or even raise the risks of impact.


French, along with NC State Associate Professor of Mechanical and Aerospace Engineering Andre Mazzoleni, studied the “tether and ballast” system and its potentials for success and found that the theory could actually work.

"Using a tether somewhere between 1,000 kilometers (roughly the distance from Raleigh to Miami) to 100,000 kilometers (you could wrap this around the Earth two and a half times) to divert an asteroid sounds extreme. But compare it to other schemes," French says, "They are all pretty far out. Other schemes include: a call for painting the asteroids in order to alter how light may influence their orbit; a plan that would guide a second asteroid into the threatening one; and of course, there are nukes. Nuclear weapons are an intriguing possibility, but have considerable political and technical obstacles. Would the rest of the world trust us to nuke an asteroid? Would we trust anyone else? And would the asteroid break into multiple asteroids, giving us more problems to solve?"

Such Earth strikes have occurred before with devastating results.  A very large asteroid is contributed with the extinction of dinosaurs millions of years ago. As early as 1907, a mysterious airburst from an apparent comet flattened a forest in Siberia the approximate geographic size of New York City.


As recently as March 2009, a cosmic surprise whizzed by Earth, only 40,000 miles away or about one-seventh the distance to the Moon. The relatively small asteroid was discovered only a couple of days before passing close to the Earth and some experts proclaim that if it had struck the Earth or entered its atmosphere, it could have had the explosive effect of a nuclear blast.


The research entitled, “Trajectory Diversion of an Earth-Threatening Asteroid via Elastic, Massive Tether-Ballast System,” will be presented in September at the American Institute of Aeronautics and Astronautics SPACE 2009 Conference and Exposition in Pasadena, CA.