A system for Earth defense from asteroid and comet hazard on the base of super-power gamma-laser
The report on international programme for Earth defense from asteroid-comet hazard
Space Laser
The report on international programme for Earth defense from asteroid-comet threat is prepared under a Russian Federation patent from 27.12.2004 (RU 2243621 C1 “Method and device for generation of directed and coherent gamma-radiation”. In this patent under physico-mathematical and quantum analysis as well as work over constructional and technical details there is shown a unique and real way of defense a human civilization from a ruthless outer space.
Today a threat of Earth collision with outer space objects is concerned by the world community as a really existing one. The problem is that there has been no proper defense method until nowadays. A purpose of this paper is to present an effective, financially and technically realizable solution of this problem which was processed by Russian scientists. It is a matter of integration of scientific, technical and financial capabilities of international scientific community for creation of a weapon for the Earth defense - a high-powered compact space laser. The paper is focused on showing proofs for current possibility and necessity of launching a practical work in this direction.
The authors of the laser used a complex approach in physical target setting for nuclear charges development. A detailed analysis of physical processes in the moment of a nuclear explosion allowed the authors to combine physically a nuclear pumping zone with a crystal – an active medium of the laser. Such a combination allows getting a powered impulse beam of directional and coherent X-ray emission and gamma rays with emissive power of 1017Watt / cm2.
A device represent a monocrystal of uranium hydride in the form of cylinder with such critical geometrical dimensions under which a path length of a neutron coincides with typical cross section of a reactor and a source of prompt neutrons for initiating a wavefront of chain fission reaction along the reactor (Fig. 1).
Figure 1.
General physical illustration of beaming and emitting a directional and coherent X-ray and gamma rays
In the process of slowing down neutrons of the source up to thermal energies on hydrogen nucleuses there formed a neutron wave of coherent neutrons yielded in the result of diffraction scattering within intercrystalline planes. Neutrons of the neutron wave are absorbed by heavy nucleuses and cause initiating a wave front of coherent excited nuclei (likeness of inverse population) and as a consequence a wave front of chain fission reactions with fast neutrons emission (likeness of positive feedback and intensification) and coherent emission of gamma-quantums.
A direction of neutron motion along the reactor with following directed emission is determined from one hand by small slowing-down length of prompt neutrons comparable with the reactor diameter and from the other hand by cylindrical shape of the device. Thus design dimensions of the reactor fit with critical geometrical dimensions of the monocrystal of uranium hydride and accordingly with dimensions of gamma-laser’s active medium. The neutron wave moves with a speed of thermal neutrons along the monocrystal from its beginnings due to slowing down prompt neutrons of the internal source. The wave is intensified in the result of initiating of a chain fission reaction of uranium nuclei and yielded as a beam of coherent neutrons from the opposite end. Simultaneously with the motion of the neutron wave a wave of chain fission reaction and coherent gamma-quantums there initiated. The rest of neutrons and emissions disperse.
After above-mentioned wave processes a motion of reactor’s evaporation front (nuclear explosion front) takes place due to absorption of debris’s energy as a result of initiating a chain fission reaction. A motion speed of the evaporation front increases as far as moving along the reactor. A volume of a radiant flux of prompt neutrons of the source is chosen in such a way as the evaporation front could not reach and destroy the neutron wave.
A beam of both coherent and noncoherent X-ray and gamma radiation coming out from the action end face of the laser as well as a beam of coherent thermal neutrons has a destructive force of about of 105 km. The duration of its impact is determined by the time the neutron wave moves from the point of its formation to the action end face and is equal to about of 10-3 s. The emission of X-ray and gamma-quantums moves in space with the velocity of light and carries sufficiently a large part of nuclear explosion energy.
A method for increasing an explosion time from 10-9 s to 10-3 s is the main factor which provides efficiency of the device. In particular increase in time of pumping allows to transform effectively nuclear explosion energy into a laser beam of gamma-quantums (by analogy with physical processes in quantum electronics).
Basic construction diagram of the gamma-laser is presented on Fig. 2 – “An isometry of the gamma-laser device in axial section in a prelaunch (precritical) state” and Fig.3 - “An isometry of the gamma-laser device in axial section in the moment of start, at the time of a contact of active medium butt-end of the monocrystal with the surface of the prompt neutrons source”.
Figure 2.
An isometry of the gamma-laser device in axial section in a prelaunch (precritical) state
Figure 3.
An isometry of the gamma-laser device in axial section in the moment of start, at the time of a contact of active medium butt-end of the monocrystal with the surface of the prompt neutrons source
A presented method of increasing duration of nuclear explosion approximately in million times (from one milliardth to one thousandth of a second) also critical dimensions and geometry of the reactor-crystal allow to transform effectively the energy of nuclear reaction into laser’s gamma beam with a cross-section of 3 centimeters and a rate of flow approximately of 1017 watt for a square centimeter which is approximately equal to explosion of a megaton nuclear bomb. In Russia there are technologies and experience for creation of a specific material for the crystal of such a laser. For all that the weight of the crystal is only about one hundred kilograms.
A deflection or a destruction of a comet nucleus or dangerous asteroid by the laser’s impact combines in it a relative simplicity of a distance impact with an effectiveness of a deep thermonuclear explosion (Fig. 4). From one hand when the beam impacts under a dangerous space object from a formed well with depth of many meters there is occur an outflow of an object substance heated up to one hundred thousand degrees. As a consequence a jet draft occurs, which changes in a required way a moving trajectory of the dangerous object. From the other hand spreading in the object shock waves will destruct it from inside causing loses of its surface.
Figure 4.
General illustration of processes inside an asteroid-target (hazardous near-Earth object – HNEO) under the gamma-laser’s beam impact
Equipped with such a laser space devices may become a key element of the Earth defense system from asteroid-comet hazard. Super power gamma laser allows to intercept dangerous for the Earth objects in the widest range of relevant velocities and trajectories, at significant mistakes of calculated meeting point, at distances of hundreds and thousands kilometers from the object, staying far away from a zone of possible damage of interceptor-device by particles, which sometimes surround space objects for instance comet nucleus.
Not large mass and dimensions parameters of the laser device give wide possibilities of variation necessary impacts upon the object by implementing “battery fire” of several lasers settled under one device-interceptor or consecutively “fire” the object from several small devices. It becomes possible to use light and middle rockets with short time of readiness for leading out a device to a meeting trajectory with the object, also becomes possible to use rockets of a middle class for leading out interceptors to high velocities trajectories of “the sooner meeting” for an earlier impact upon the dangerous object.
Relative cheapness of the system at criteria costs/result, high ecological safety caused by a stability of the device for destruction as a result of a rocket crash, possibility of carrying out a wide range of non-nuclear tests of the system’s separate elements at the first stage gives a base for a state that the presented project is the most perspective nowadays.
Basic parameters of the device
The parameter
Volume
Wave length
10-13 cm (for Γ-quantum the energetic parameter is used)
Quantum energy
9-10 MeV
Energy density
1015 - 1017 W/sm2
Diffraction scattering
< 10-10
Equivalent energy of nuclear explosion
1 MT
Γ-radiation efficiency (the power radiated to the total power)
30%
Impulse duration
10-3 s
Amount of impulses
1
Maximum distance of effective impact on the object
108 m
Material of a reactor-crystal
uranium hydride monocrystal
Total weight of a reactor-crystal
100 kg
Length of crystal-reactor
100 cm
Reactor diameter
3 cm
Broad-brush estimates for superdense and ultrastrong object (“the worst variant”) with a diameter of 100 meters showed following results:
Characteristics of an object
The parameter
Volume
Density
20 g/cm3
Diameter of an object
100 m
Electronic charge of object matter
100
Velocity of sound in an object substance
3-5 km/s
Critical mechanic durability
103J/sm3 (for ordinary substance ~102J/sm3)
Transpiration temperature of the object substance
5 000 K
Physics of interaction
The parameter
Volume
Multiple Compton scattering at electrons
to depth of 0.3 - 4 m
Heat conduction of a beam
to depth of 4 - 7 m
Electronic charge of object matter
3-5 km/s
Temperature of heating at depth of 0.3 - 10 m
up to 100 000 K
Diameter of produced channel
1 - 2 m
Pressure in the channel
105- 107 J/cm2
Critical length of destroying material by impact wave
3 m
The amount of impulses necessary for giving to an object velocity of 1 m/s caused by the occurrence of jet traction from a hole (without taking into account actions of a shock wave)
10 - 20
Calculations also show that for objects of normal density and strength the necessary amount of impulses of action decreases for the order. Besides a complete destroying of an object to small components (as a result of action of shock waves from individual impulses) is probable for "standard" space objects of size about tens - hundreds meters (Fig. 5).
Figure 2.
An isometry of the gamma-laser device in axial section in a prelaunch (precritical) state
Application of the device (transferring a significant part of nuclear explosion energy to significant distances) for impact on dangerous space object opens a range of advantages in comparison with other methods of impact (including nuclear and the kinetic impacts):
- application of the device in the widest range of cross velocities and trajectories (of a device-interceptor and dangerous object) is possible;
- application of the device in case of significant mistakes of the calculated point of a meeting is possible;
- application of the device in case of significant distances from an object is possible, staying outside of a zone of probable damaging a device - interceptor by particles which may surround some space objects, for example comet nucleus.
Small mass-dimensional parameters of the device that allow:
- to scale necessary power influence on the object by using several devices on the one device - interceptor or consecutive influencing on the object by several light devices - interceptors;
- to use small and medium-lift launch vehicle with short term of readiness for start-up (including typical strategic ballistic missiles) for ascent to a trajectory of a meeting with object;
- to assign to devices - interceptors, if necessary, significant speeds with use of trajectories of "prompt meeting" for earlier influence on dangerous object;
- high reliability of the device and simplicity of its application;
- an opportunity of realization a wide spectrum of tests (in case of achievement the certain political conditions, including trial device tests);
- relative cheapness at criterion "expense/result" in comparison with other systems;
- an opportunity of creation a grouping of devices - interceptors of long constant readiness on the basis of the device;
- destruction tolerance of the device resulting case of failure of the rocket - carrier at a stage of ascent the object to a trajectory of a meeting with a dangerous space object;
- an opportunity of realization the universal control of safety at all stages of the manipulation with the device by standard ways and the means that used today to nuclear devices of low power.
Collisions of the Earth with asteroids took place in the past and will happen in the future. Nobody knows when but it will happen inevitably. May be in hundreds years time or may be next Friday the mankind will be given a dare - a dare of the heaven in the true sense of the word.
Today we would have no chance. It is a great luck to catch sight of an “Apocalypse star” for a half-year before a collision and for smaller objects this period may be weeks or even days. Space interceptors with thermonuclear bombs or superheavy kinetic shell similar to the Deep Impact but in thousand times more massive in theory could take away the threat of a collision in favorable conditions but for their development and construction many years and billions of dollars are needed. Calls to begin a creation of such a global defense system beforehand “to be on the safe side” are not reasonable. However when the threat will become obvious there will be no time to do something. A system of interception of hazardous space objects based on a technology of the high-powered gamma-laser is cheaper in ranges and more effective. It is not difficult to stock up such a system beforehand. It is time.
Vice-president “S.P. Korolev Rocket & Space Corporation ENERGIA”,
ńurator, technical advisor to the project "Gamma-laser" implemented by
non-profit organization to support scientific technical research
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