Alternative, at times unusual, mitigation methods
People have come up with many interesting ideas to help save the Earth from an asteroid impact. Some time will be spent during the NEOShield project to filter through some of the more exotic of these ideas to see if there are any that could be applied to a real mission, capable of moving an asteroid from its initial course.
Here are some that will be considered.
Moving asteroids with lasers:
There are two broad ideas discussed in papers related to moving asteroids with lasers. Using lasers to boil off material from the asteroid surface can move an asteroid as the gas behaves just like propellant. Also, the light itself can exert a small force, so large enough lasers could potentially move smaller asteroids.
Focusing the Sun’s energy:
The use of large mirrors or lenses to concentrate the Sun’s energy onto an asteroid using single or multiple spacecraft is an idea that has been discussed in numerous publications.
Changing an asteroid’s thermal properties:
The orbit of an asteroid is effected by its thermal properties so it stands to reason that changing the overall thermal properties of an asteroid should result in a change of its orbit. Many ideas have been suggested as to how this can be achieved: from painting an asteroid white, to shading it from the Sun.
Electrostatic methods are often described as having much greater potential than gravity-based methods of asteroid deflection since the electrostatic force is so much stronger than gravity. The project will explore the effectiveness of using electrostatics to push an asteroid off course.
The purpose of investigating the more exotic alternative methods of moving an asteroid is to ensure the NEOShield project is comprehensive. It is not intended to dismiss any ideas out of hand, but instead to ensure that the best methods of asteroid deflection are carried forward into the future.
(Image courtesy Astrium)