Russia has been and remains the leader in the field of nuclear space energy. Organizations such as RSC Energia and Roscosmos have experience in the design, construction, launch and operation of spacecraft equipped with a nuclear source of electricity. A nuclear engine allows you to operate aircraft for many years, repeatedly increasing their practical suitability.
Historical record
The use of nuclear energy in space has ceased to be fiction back in the 70s of the last century. The first nuclear engines in 1970-1988 were launched into space and successfully operated on spacecraft (SC) observation "US-A". They used a system with a Buk thermoelectric nuclear power plant (NPP) with an electric power of 3 kW.
In 1987-1988, two Plasma-A spacecraft with a Topaz 5 kW thermal-emission nuclear power plant underwent space flight tests, during which electric rocket engines (ERE) were powered for the first time from a nuclear energy source.
A complex of ground-based nuclear energy tests of the Yenisei thermionic nuclear installation with a capacity of 5 kW was completed. Based on these technologies, projects of thermionic nuclear power plants with a capacity of 25-100 kW have been developed.
MB "Hercules"
RSC Energia in the 70s began scientific and practical research aimed at creating a powerful nuclear space engine for the Hercules interorbital tug (MB). The work allowed us to make a reserve for many years in terms of a nuclear electric rocket propulsion system (NERP) with a thermionic nuclear power plant with a power of several to hundreds of kilowatts and electric rocket engines with a unit power of tens and hundreds of kilowatts.
Design parameters of MB "Hercules":
- useful electric power of nuclear power plants - 550 kW;
- specific impulse of electric propulsion system - 30 km / s;
- thrust of the electric propulsion system - 26 N;
- resource of nuclear power plants and electric propulsion systems - 16,000 hours;
- working body of electric propulsion system - xenon;
- the mass (dry) of the tugboat is 14.5-15.7 tons, including nuclear power plants - 6.9 tons.
Latest time
In the 21st century, it is time to create a new nuclear engine for space. In October 2009, at a meeting of the Presidential Commission on Modernization and Technological Development of the Russian Economy, the new Russian project “Creating a transport and energy module using a megawatt-class nuclear power plant” was officially approved. The head developers are:
- The reactor facility is NIKIET OJSC.
- A nuclear power plant with a gas turbine energy conversion circuit, an electric propulsion system based on ion electric rocket engines and a nuclear propulsion system as a whole - SSC Research Center named after MV Keldysh ”, which is also the responsible organization for the development of the transport and energy module (TEM) as a whole.
- RSC Energia, as the general designer of the TEM, should develop an automatic device with this module.
Characteristics of the new installation
Russia plans to launch a new nuclear engine for space in commercial operation in the coming years. The alleged characteristics of a gas turbine nuclear power engine are as follows. A gas-cooled fast neutron reactor is used as the reactor, the temperature of the working fluid (He / Xe mixture) in front of the turbine is 1500 K, the conversion efficiency of heat into electrical energy is 35%, and the type of refrigerator-emitter is drip. The mass of the power unit (reactor, radiation protection and conversion system, but without a refrigerator-emitter) is 6,800 kg.
It is planned to use space nuclear engines (nuclear power plants, nuclear power plants together with electric propulsion systems):
- As part of future space vehicles.
- As sources of electricity for energy-intensive systems and spacecraft.
- To solve the first two problems in the transport and energy module for providing electric rocket delivery of heavy spaceships and vehicles to working orbits and further long-term power supply of their equipment.
The principle of operation of a nuclear engine
It is based either on the synthesis of nuclei, or on the use of fission energy of nuclear fuel to form reactive thrust. Distinguish installations pulse-explosive and liquid types. An explosive installation throws miniature atomic bombs into space, which, detonating at a distance of several meters, push the ship forward in an explosive wave. In practice, such devices have not yet been used.
Liquid nuclear engines, by contrast, have long been developed and tested. Back in the 60s, Soviet specialists constructed a workable model RD-0410. Similar systems were developed in the USA. Their principle is based on heating a liquid with a nuclear mini-reactor, it turns into steam and forms a jet stream, which pushes the spacecraft. Although the device is called liquid, hydrogen is usually used as the working fluid. Another purpose of nuclear space installations is to power the on-board electrical network (devices) of ships and satellites.
Heavy telecommunications apparatus for global space communications
At the moment, work is underway on a nuclear engine for space, which is planned to be used in heavy space communications equipment. RSC Energia carried out research and design work on a system of global space communications economically competitive with cheap cellular communications, which was supposed to be achieved by transferring the telephone exchange from Earth to space.
The prerequisites for their creation are:
- almost complete filling of the geostationary orbit (GSO) with working and passive satellites;
- exhaustion of the frequency resource;
- positive experience in the creation and commercial use of informational geostationary satellites of the Yamal series.
When creating the Yamal platform, new technical solutions amounted to 95%, which allowed such devices to become competitive in the global space services market.
It is planned to replace modules with technological communication equipment approximately every seven years. This would make it possible to create systems of 3-4 heavy multifunction satellites on GSO with an increase in the electric power consumed by them. Initially, spacecraft based on solar batteries with a capacity of 30-80 kW were designed. At the next stage, it is planned to use 400 kW nuclear engines with a resource of up to one year in transport mode (for delivery of the base module to GSO) and 150-180 kW in continuous operation mode (at least 10-15 years) as a source of electricity.
Nuclear engines in the Earth's anti-meteorite defense system
Design studies carried out by RSC Energia at the end of the 90s showed that in the creation of an anti-meteorite system to protect the Earth from comet and asteroid nuclei, nuclear-electric installations and nuclear power engines can be used for:
- Creation of a system for monitoring the trajectories of asteroids and comets crossing the Earth’s orbit. To do this, it is proposed to arrange special spacecraft equipped with optical and radar equipment for detecting dangerous objects, calculating the parameters of their trajectories and the initial study of their characteristics. The system may involve a nuclear space engine with a dual-mode thermionic nuclear power plant with a power of 150 kW or more. Its resource must be at least 10 years.
- Tests of means of influence (explosion of a thermonuclear device) on a landfill safe asteroid. The power of a nuclear power engine to deliver a test device to an asteroid test site depends on the mass of the delivered payload (150-500 kW).
- Delivery of standard means of influence (interceptor with a total mass of 15-50 tons) to a dangerous object approaching the Earth. A nuclear engine with a power of 1-10 MW will be required to deliver a thermonuclear charge to a dangerous asteroid, whose surface explosion due to the jet stream of the material of the asteroid can deflect it from the dangerous trajectory.
Deep Space Research Equipment Delivery
The delivery of scientific equipment to space objects (distant planets, periodic comets, asteroids) can be carried out using space stages based on LRE. It is advisable to use nuclear engines for spacecraft when the task is to enter the orbit of a satellite of a celestial body, direct contact with the celestial body, sampling substances and other studies that require an increase in the mass of the research complex, including the landing and take-off stages.
Engine Parameters
The nuclear engine for the research complex’s spaceships will expand the “launch window” (due to the controlled expiration rate of the working fluid), which simplifies planning and reduces the cost of the project. Studies performed by RSC Energia have shown that a 150 kW NREP with a resource of up to three years is a promising means of delivering space modules to the asteroid belt.
At the same time, the delivery of the research apparatus to the orbits of the distant planets of the solar system requires an increase in the life of such a nuclear installation to 5-7 years. It has been proved that the complex with a nuclear power generating facility with a power of about 1 MW as part of a research spacecraft will allow for accelerated delivery in 5-7 years to the orbits of artificial satellites of the most distant planets, planet rovers to the surface of the natural satellites of these planets and the delivery of soil from comets, asteroids, Mercury and satellites of Jupiter and Saturn.
Refillable tug (MB)
One of the most important ways to increase the efficiency of transport operations in space is the reusable use of elements of the transport system. A nuclear engine for spaceships with a capacity of at least 500 kW allows you to create a reusable tugboat and thereby significantly increase the efficiency of a multi-link space transport system. Such a system is especially useful in the program for ensuring large annual cargo flows. An example is the program of moon exploration with the creation and maintenance of a constantly expanding habitable base and experimental technological and industrial complexes.
Cargo calculation
According to the design studies of RSC Energia, during the construction of the base, modules weighing about 10 tons should be delivered to the lunar surface, up to 30 tons into the orbit of the moon. The total cargo flow from the Earth during the construction of the inhabited lunar base and the visited lunar orbital station is estimated at 700-800 tons , and the annual cargo flow to ensure the functioning and development of the base is 400-500 tons.
However, the principle of operation of the nuclear engine does not allow to disperse the transporter quickly enough. Due to the long transportation time and, accordingly, the significant time spent by the payload in the radiation belts of the Earth, not all cargo can be delivered using tugboats with a nuclear engine. Therefore, the cargo flow that can be provided on the basis of nuclear power generation is estimated only at 100-300 tons / year.
Cost effectiveness
As a criterion of economic efficiency of the interorbital transport system, it is advisable to use the value of the unit cost of transporting a unit mass of payload (GH) from the Earth's surface to the target orbit. RSC Energia has developed an economic and mathematical model that takes into account the main cost components in the transport system:
- to create and put into orbit tug modules;
- for the purchase of a working nuclear installation;
- operating costs, as well as R&D expenses and possible capital costs.
Cost indicators depend on the optimal parameters of MB. Using this model, the comparative economic efficiency of the use of a reusable tugboat based on a nuclear power propulsion system with a capacity of about 1 MW and a disposable tugboat based on promising liquid rocket engines was studied in a program to ensure delivery from Earth to the orbit of the moon with a height of 100 km of payload with a total mass of 100 t / year. When using the same launch vehicle with a payload equal to the payload of the Proton-M launch vehicle and a two-launch scheme for constructing a transport system, the unit cost of delivering a unit of mass of payload using a tug-boat based on a nuclear engine will be three times lower than when using disposable tugboats based on rockets with liquid engines of the DM-3 type.
Conclusion
An effective nuclear engine for space helps to solve the Earth’s environmental problems, man’s flight to Mars, the creation of a wireless energy transmission system in space, the implementation with increased safety of the disposal of especially dangerous radioactive waste from terrestrial nuclear energy in space, the creation of a habitable lunar base and the beginning of the industrial exploration of the Moon, ensuring Earth protection from asteroid-comet hazard.