Logvinenko A. A., Mitikov U. A., Timoshenko Zh. I.

Oles Honchar Dnipropetrovsk National University

PERSPECTIVES OF NUCLEAR ROCKET ENGINES DEVELOPMENT

The propulsion system on the spacecraft Board are designed to create thrust force or momentum. The type of propulsion thrust divided into chemical (DS) and non-chemical (NCHRD). DS are divided into liquid (LRE), solid fuel (RESF) and combined (MRC). In its turn, non-chemical propulsion share on nuclear (YARD) and electric (ERD). The great scientist Konstantin Tsiolkovsky a century ago created the first model of the propulsion system, which worked on firm and liquid fuel. Then, in the second half of the 20th century thousands of flights using primarily the solid-propellant LPRE were made.

Currently, however, for flights to other planets, not to mention the stars, the use of solid-propellant rocket engine becoms more disadvantageous though many of KMG were developed. Most likely, possibilities of rocket engines and solid rocket motor has come to end. The reason here is that the specific impulse of all chemical KMG low and does not exceed 5000 m/s, which requires for the development of a sufficiently high speeds of long-term operation of the remote control and consequently large reserves of fuel or, as it is in space, the necessary large number of Tsiolkovsky, i.e. the ratio of the mass of filled missiles to the empty weight. So PH Energy, leading to a low orbit 100 tons of payload, has a launch mass of about 3 000 tonnes, which provides for a number of Tsiolkovsky is within 30.

For a flight to the example on Mars number Tsiolkovsky should be even higher, reaching values of 30 to 50. Easy to appreciate that when the useful cargo of about 1 000 tons, and within a certain limit varies minimum mass required to meet the needs of the crew, launched to Mars with consideration of fuel supplies for your return flight to Earth, initial mass of the SPACECRAFT should be not less than 30 000 to 50 000 tons, which obviously is beyond the level of development of modern space exploration, based on application of solid-propellant LPRE.

Thus, to achieve manned by crews even the nearest planets is necessary to develop PH engines on the principles of non chemical control. The most promising in this respect are electric jet engines (ERD), laser jet engines (JPL) and the nuclear jet (YARD).

The YARD has received its name due to the fact that create thrust through the use of nuclear energy, i.e. energy, released in nuclear reactions. In a General sense under these reactions refers to any change of the energy state atomic nuclei, as well as turning one of the cores in to the other, related to reconstruction of the structure of nuclei or modifying the number contained in them elementary particles nucleons. Moreover, nuclear reactions as known can occur either spontaneously (i. e. spontaneously) or be caused artificially, for example, the bombardment of some other nuclei (or elementary particles). Nuclear reactions of fission and fusion on the energy surpass chemical occure reaction respectively in the millions and ten millions of times. This is explained by the fact that the energy of the chemical bonds of the atoms in molecules is many times less energy nuclear communication of nucleons in the nucleus. Nuclear energy in the rocket engines can be used in two ways:

1. The released energy is used to heat the working fluid, which is then expanded in the nozzle, as well as in a conventional rocket engine.

2. Nuclear energy is converted into electrical and then used for ionization and acceleration of particles of a working body.

Finally, the momentum created by fission products formed in the process of nuclear fission reaction.

At present, the problem of radiation protection of spacecraft from the YARD is in principle are also solved. The fundamental problems associated with the maintenance of the YARD on the test benches and pads. Although the operating YARD is a danger to the service personnel» within a day after the end of work in the YARD without any means of individual protection to be within a few tens of minutes at a distance of 50 m from the YARD and even to approach him. The simplest means of protection allow maintenance personnel to enter into the working area of the YARD shortly after the tests.

Most likely that in the near future the solid-phase YARD will become one of the most common RD. Solid-phase YARD can be used as vehicles for long-range flights, for example, on such planets like Neptune, Pluto, and even to fly beyond the Solar System.