Special Equipment Which Uses Concentrated Solar Light for Earth Protection Against Asteroids-Advanced Design and Technology
This paper presents advanced design and technology of special equipment (here called ‘cannon’) which uses concentrated solar light for destruction of dangerous asteroids. According to Einstein General Theory of Relativity, elliptical orbit of any cosmic body is rotating around ellipse center (i.e. the perihelion of orbit is moving continuously). On the other hand, the trajectories of cosmic bodies are permanently affected by the gravity of other cosmic bodies which are moving, too. In the case o asteroids which have relatively small masses, orbit changes can be important leading to the danger of collision with Earth. At this moment our civilization has practically no efficient and reliable mean to destroy or diverge the dangerous asteroids form their collision trajectory with Earth. The idea of the cannon which uses concentrated solar light for Earth protection against asteroids is a new one. This idea was presented for the first time by the authors of this paper in 2014. Mainly, this equipment is composed of one large and one small parabolic mirror having the same focal point and coincident axes. The mirrors are positioned face to face i.e., the concave side of the large parabolic mirror is oriented to the concave side of the small parabolic mirror. The light rays coming from Sun are focalized by the large parabolic mirror to its focal point. The light rays are then reflected by the small parabolic mirror (which has the same focal point as the large parabolic mirror) in parallel rays along the parabola axis. The beam of concentrated light having diameter ‘d’ equally to the diameter of small parabolic mirror passes through one hole having diameter ‘d+’ placed in the center of large parabolic mirror. An articulated mirror tube is fixed on the convex side of the large parabolic mirror by means of a spherical articulation. This mirror tube is used for directing of the concentrated light beam toward the asteroid. The power of canon is of the order of terawatts and it can vaporize for example an iron asteroid of 100 tones in seconds. If asteroid too heavy, the concentrated light beam can vaporize only locally the asteroid matter and the reaction force created by vapours will deviate the asteroid from the collision trajectory with Earth. Due to the high speed of light, this type of canon can hit the asteroid when it is still at a long distance by Earth. The cannon can be built on an orbit around the Earth and then it can be placed on a solar orbit as the Kepler telescope. When such a cannon is placed permanently on a terrestrial orbit, it can be used for cleaning of space surrounded by debris. In this paper are done calculations of cannon mass, power and heat transfer for several diameters of the large and small parabolic mirrors. The paper presents advanced design of mirrors based on hexagonal, square or triangular cells and a new technology for manufacturing of reflecting foils of mirrors. The resistance structure of mirrors is composed of multiple hexagonal, square or triangular cells made of titanium tubes having very thin walls. The titanium tubes are gold plated for a good reflectivity. The reflective material of mirrors is a gold plated graphene foil which is lighter and stronger than the classic material Mylar. The gold has a high reflectivity and the graphene strongly dissipates the heat in space through radiation as a black body. In this way, the both parabolic mirrors are intensively cooled. The gold plated graphene foil is stretched on the hexagonal, square or triangular cells composing the resistance structure of mirrors. This equipment which will operate near Earth will be the subject of natural bombardment with particles of the so called unorganized matter of Universe (micrometeorites, interplanetary dust and gas, solar wind, cosmic radiation, etc.). The effect of unorganized matter on equipment integrity and operating capacity is be analysed in this paper. This analyse will permit evaluation of equipment active life in space. The advanced design and technology presented in this paper is a basis for development of design and technology of real equipment placed in space for Earth protection against asteroids and cleaning the space by debris.