New Delhi: Asteroids have a variety of compositions, and can be carbonaceous, silicaceous or metallic. They can also be compact objects or loosely-held together rubble piles. NASA is developing a number of innovative techniques to deflect asteroids, including kinetic impactors, gravity tractors, ion-beam shepherds and nuclear explosives. Directed energy machines are among the promising methods for deflecting asteroids, but scientists have to first understand how these energy pulses can deflect the various types of asteroids. Demonstrating such technologies in space is expensive and challenging, which is why researchers at the US Sandia National Laboratories are finding out through experiments in a controlled lab environment.
The researchers used the Z machine at Sandia which is the most powerful pulsed-power machine on the Earth. The machine fires rapid pulses of X-rays. The researchers used a sophisticated technique called X-ray scissors to briefly suspend material simulating asteroids, to counter the influence of gravity. In the experiment, the researchers placed a tenth of a gram of silica on a fine foil eight times thinner than human hair, and then fired the X-rays at the foil. The foil instantly vapourised, allowing the researchers to carefully measure how the simulated asteroid responded to the energy burst. The burst of X-rays lasted for 20 millionths of a second, measuring 12.5 millimetres across, or about the width of a finger.
Tabulating the responses of asteroids
The researchers now want to use the same technique to discover how simulated material of various different kinds of asteroids will respond to the X-ray pulses. This data will provide scientists with valuable insights on the amount of energy necessary to deflect any given asteroid, once its composition has been determined using remote observations or flybys. Lesser energy is required to push a potential impactor on a safer trajectory, provided it is detected early. This is why it is necessary to improve planetary defence capabilities to track and identify potentially hazardous asteroids, years, and preferably decades in advance. A simulated NASA exercise conducted earlier in the year indicated that the world governments will respond sluggishly to a potential impactor.
