Thousands of near-Earth asteroids are currently known to astronomers, many of which may ultimately pose a potential threat to our existence. According to a group of researchers, high mass objects, or space impactors, might be capable of deflecting some of these impact events, thereby preventing a global extinction event.
Scientists conjecture that a colossal impact transpired almost 65 million years ago, wiping out much of the life that existed on earth at the time. Scientists base some of their evidence on the enormous, prehistoric Chicxulub crater, located in Mexico. The impact has been traced back to the Cretaceous-Paleogene boundary and is approximately 180km in diameter, representing one of the largest impact formations perceived on earth. Estimates suggest the flaming bolide, responsible for creating the aforementioned crater, was 10km wide.
In addition, the presence of shocked quartz and tektites (terrestrial debris) corroborates scientists’ tentative theory that the Chicxulub crater was the result of a massive asteroid/meteor impact. The debate, however, continues to rage over precisely what type of body was involved and whether it was the sole cause of the extinction event.
But how do we prevent these cataclysmic occurrences from befalling mankind? Frank Schäfer of the Fraunhofer Institute for High Speed-Dynamics, in Freiburg, considers he might just have the answer. His institute is a small part of the NEOShield project, which seeks to further our understanding of near-Earth objects and prevent potentially devastating collision events.
Schäfer has been conducting numerous experiments into asteroid deflection, simulating the events using smaller scale models. He equates it to a game of billiards, but on a much grander scale, taking into consideration asteroids that could annihilate entire cities. He looked at an aluminum projectile, capable of soaring to speeds of 10 kilometers per second, to determine the influence of projectiles on rerouting earth-bound objects.
The idea behind the project is to fire an enormous object towards the asteroid, in a bid to trigger its deflection away from earth and prevent damaging impacts and extinction events. Once an object’s trajectory has been confirmed to be inbound for earth, a high-mass space impactor could be propelled towards the asteroid. The kinetic energy of such a device is only part of the reason for the object’s diversion, however. During the artificial impact event, chunks of the asteroid will cast off as debris. This debris will also have its own recoil, which will act to oppose the original trajectory of the asteroid body.
According to The International Business Times, the ejecta could improve the transfer of momentum between the fired missile and the asteroid body by as much as four times. However, during Schäfer’s experimental investigation, this transfer was dependent upon the consistency and porosity of the body in question. The aluminum projectiles were more successful in diverting high density objects, than when compared to objects comprised of highly porous material.
The NEOShield website refers to this technique as a “kinetic impactor mitigation method,” using momentum transfer between a launched spacecraft, or probe, and the near-earth object. The principles behind this method are redundant, however, unless early detection and warning systems are not put in place.
The asteroid body’s trajectory will only change by a small fraction with time. Therefore, according to Schäfer, it is imperative that the spacecraft-asteroid collision event occurs years in advance of its impact with earth to maximize its effect. Therefore, observer spacecraft are imperative to monitor the direction, magnitude, rotation and composition of a dangerous object before launch and after successful collision.
These new techniques are likely to be critical in developing a viable plan to prevent dangerous near-earth objects from colliding with our planet. Almost 10,000 asteroids, which have a trajectory path in close proximity to that of earth’s orbit, have been discovered so far. In the future, these space impactor systems could provide clues as to how much larger asteroids, capable of causing extinction level events, might be diverted.
By: James Fenner