Researchers have discovered thousands of near-Earth asteroids and some of those objects may, potentially, pose a threat to the planet. Deflecting an asteroid could prevent a catastrophe on Earth and researchers are currently testing possible methods to push a potential threat off course and way from the planet.
Frank Schäfer, from the Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI in Freiburg, has researching asteroid deflection in a lab on a much smaller scale. The institute is a part of the international NEOShield Project which researches possible defense, or detection methods, of near-Earth Objects (NEOs).
Instead of lasers, or advanced technology, Schäfer is focusing on objects with heavy mass that can crash into these asteroids, causing them to change their trajectory safely away from Earth. Schäfer describes the asteroid deflection as having the same principles as a game of billiards, except with large space probes and an asteroid threat to Earth.
The experiments focus on an object with a lot of mass crashing into an asteroid at a fast speed. When the object hits the asteroid, there is some debris that gets knocked off the asteroid which helps propel the potential threat away from Earth. Schäfer said in a statement, “During impact, not only does the probe transfer its own momentum to the asteroid, there is also the recoil of detached material from the crater, which is ejected against the direction of the impact. This recoil effect acts like a turbocharger on the deviation of the asteroid.”
The ejected material greatly enhances the momentum transfer, up to four times the amount, which could help the feasibility of such a project as the object does not have to be as massive to effectively push an asteroid away. The experiments testing momentum transfer revealed objects made with more porous material, such as concrete, had less momentum transfer than objects made of denser material. Researchers used an aluminum projectile that could reach speeds of 10 km/s (around 6 miles per second) and these projectiles pushed the asteroids just enough to prevent a collision with Earth.
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The biggest factor involved with asteroid deflection is detection. “The impact of a space probe would change the speed of the asteroid by just a few centimeters per second. But that’s enough to deflect its course to a significant degree over a longer period. So if we want to stop an asteroid on collision course with the Earth from hitting us, we’ll need to fire at it many years ahead of time,” said Schäfer. While the idea of lasers being used to deflect asteroids could become a reality, it may be more practical to use a large space probe to avoid any doomsday scenario.