Photo by Jason Major
Technology / Asteroids

Cosmic Bombs: Defending the Earth from the Asteroid Threat

Last February, a meteor exploded 28 miles above the city of Chelyabinsk, Russia, producing a devastating shockwave that knocked people off their feet and shattered windows throughout the city. Traveling at 12 miles per second, the 20-meter wide space rock exploded with the energy of around 500 kilotons. At its peak, the streaking fireball glowed 30 times brighter than the sun and caused 1,210 cited injuries, mostly from falling building debris, flying glass, and extreme burns.

The unforeseen catastrophe sparked an international outcry for protection against asteroids. NASA has long urged government officials to implement an asteroid-fighting group, and the incident in Chelyabisnk  prompted the United Nations General Assembly to approve the creation of an International Asteroid Warning Group, which will collaborate with the UN Committee on the Peaceful Uses of Outer Space (COPUOUS), formed in 1959 shortly after the launch of Sputnik to organize international negotiation on the peaceful uses of outer space. Under the plan, nations will discuss and share information about hazardous space rocks. If they detect a dangerous asteroid within earth’s vicinity, COPUOUS will help the International Asteroid Warning group coordinate missions to deflect the asteroid.

While the United Nations has successfully orchestrated the political collaborations to form a plan of detection and deflection, the components still require research funding and delegation until they can be implemented. Perhaps the most incomplete portion of the plan is the preparation stage, which calls on individual countries to conduct research pertaining to asteroid detection and develop backup plans in case the International Asteroid Warning Group fails to detect an asteroid. At present, however, no country has delegated the task of planetary defense to a particular agency, and NASA’s duties do not include the deflection of asteroids. COPUOUS, for its part, has organized a plan of its own to conduct research and delegate tasks to nations, but lacks the capacity to enforce this strategy. Additionally, the Association of Space Explorers is pressuring the United Nations to set up deflection missions to test the technologies for pushing hazardous rocks off course.

While governments have yet to prioritize the threat of asteroids enough to organize committees and fund resources to preventing galactic threats, astronauts and scientists have long contemplated methods of detection and deflection. The world’s first asteroid-fighting nonprofit, B612, founded by former astronaut Ed Lu, has offered to privately finance an asteroid-detecting infrared telescope, the Sentinel Space Telescope, which is expected to be completed by 2017 and launched the following year. The Sentinel Space Telescope allows scientists to view and track 90 percent of the asteroids larger than 140 meters in Earth’s region of the solar system. The Sentinel will be launched into a Venus-like orbit around the sun, and will operate for five and a half years, during which the telescope will create a map of the solar system around Earth.

After detecting the asteroid, deflection is the last, and possibly most complicated component of defending Earth. If spotted five or ten years away, slight alterations to an asteroid’s pathway can sufficiently derail its movement toward the Earth. COPUOS has developed multiple potential methods to detect the asteroid, such as using a nuclear explosive device to deflect the space-rock. This plan would not aim to destroy it through a nuclear explosion, which would cause chunks of debris to head towards the earth. Instead, scientists believe that a blast’s intense radiation could steer the asteroid in different direction.

A slightly simpler solution would be to shoot a kinetic interceptor towards the asteroid in order to nudge it off course. According to a one mile-per-hour(AP Style?) impact would be enough to divert an asteroid by 170,000 miles if it were hit 20 years before its predicted collision.

A slightly more unconventional approach suggests painting the asteroid different colors. Because black is known to absorb solar radiation and white to reflect it, painting part of an asteroid white would create a push from solar radiation in the direction of the black section. Paint alone could cause the asteroid to veer off its original path, and save earth from a catastrophe. An alternative method involving the radiation of the Sun involves attaching a solar sail to the surface of the asteroid. The structure, once unfurled, would reflect solar radiation and gently push an asteroid out of its original path. While we’ve landed unmanned vessels on asteroids before, experts question our ability to get close enough to an asteroid to paint it or attach something as complex as a solar sail.

If none of these work, NASA could shoot a large probe into the atmosphere in the vicinity of the asteroid. The probe would not crash into it, rather, it would move to a “station-keeping position” near the space rock, pulling it into orbit using its own gravity. This probe would have to be shot directly into the path of the asteroid in order to push against the asteroid enough to counter any towing action by gravitational pull.

With all these potential solutions in mind, Lu remains on guard. “There are 100 times more asteroids out there than we have found,” he warns. “There are about one million asteroids large enough to destroy New York City or larger.” The implementation of the International Asteroid Warning group is a step in the right direction. While the International Asteroid Warning Group, COPUOUS and the Association of Space Explorers is encouraging authorities and countries to begin to take action through funding research and creating committees, leaders are skeptical of investing money in preventing a threat that is deemed unimportant compared to other security issues. Thorough research is necessary to implement any of these strategies, and the time is now to begin protecting earth from galactic dangers.