EURASIAN NATIONAL UNIVERSITY
Them. L.N. Gumilyov
Physics and Technology Faculty
Department of Space Engineering and Technology
REPORT
BY PRODUCTION
PRACTICE
ASTANA 2016
Introduction………………………………………………………………………...........3
1 General information on the power supply of spacecraft.……………....4
1.1 Primary sources of electricity …………………………………4
1.2 Automation of the power supply system............................................................... ….five
2 Solar space power plants …………..…………………..…......6
2.1 Solar batteries principle of operation and device………….….....6
3 Electrochemical space power plants…………………………..12
3.1 Chemical current sources………………………………………...13
3.2 Silver-zinc batteries…………………....15
3.3 Nickel-cadmium batteries……………………16
3.4 Nickel-hydrogen batteries……………………..17
4 Selection of parameters for solar arrays and buffer storages...………...18
4.1 Calculation of the parameters of the buffer tank………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
4.2 Calculation of parameters of solar panels……………………………..20
Conclusion…………………………………………………………………………….23
List of sources used……………………………………………...24
Specifications...………………………………………………………………………25
INTRODUCTION
One of the most important onboard systems of any spacecraft, which primarily determines its performance characteristics, reliability, service life and economic efficiency, is the power supply system. Therefore, the problems of development, research and creation of spacecraft power supply systems are of paramount importance.
Automation of flight control processes of any spacecraft (SC) is unthinkable without electrical energy. Electrical energy is used to drive all elements of spacecraft devices and equipment (propulsion group, controls, communication systems, instrument complex, heating, etc.).
In general, the power supply system generates energy, transforms and regulates it, stores it for periods of peak demand or work in the shade, and also distributes it throughout the spacecraft. The power supply subsystem may also convert and regulate the voltage, or provide a range of voltage levels. It frequently turns the equipment on and off and, for increased reliability, protects against short circuit and isolate faults. The design of the subsystem depends on cosmic radiation, which causes degradation of solar panels. The lifetime of a chemical battery often limits the life of a spacecraft.
Actual problems are the study of the features of the functioning of sources of electricity for space purposes. The study and exploration of outer space require the development and creation of spacecraft for various purposes. Currently the largest practical use receive automatic unmanned spacecraft to form global system communications, television, navigation and geodesy, information transmission, the study of weather conditions and natural resources of the Earth, as well as deep space exploration. To create them, it is necessary to meet very strict requirements for the accuracy of the orientation of the apparatus in space and the correction of orbital parameters, and this requires an increase in the power supply of spacecraft.
General information about the power supply of spacecraft.
The spacecraft geometry, design, mass, and active lifetime are largely determined by the spacecraft power supply system. Power supply system or otherwise referred to as power supply system (EPS) spacecraft - a spacecraft system that provides power to other systems is one of the critical systems. The failure of the power supply system leads to the failure of the entire apparatus.
The power supply system usually includes: a primary and secondary source of electricity, converting, charging device and automatic control.
1.1 Primary energy sources
Various energy generators are used as primary sources:
Solar panels;
Chemical current sources:
Batteries;
Galvanic elements;
Fuel cells;
Radioisotope energy sources;
Nuclear reactors.
The composition of the primary source includes not only the actual generator of electricity, but also the systems that serve it, for example, the solar array orientation system.
Often, energy sources combine, for example, a solar battery with a chemical battery.
fuel cells
Fuel cells have high weight and size characteristics and power density compared to a pair of solar batteries and a chemical battery, are resistant to overloads, have a stable voltage, and are silent. However, they require a supply of fuel, therefore they are used on vehicles with a period of stay in space from several days to 1-2 months.
Hydrogen-oxygen fuel cells are mainly used, since hydrogen provides the highest calorific value, and, in addition, the water formed as a result of the reaction can be used on manned spacecraft. To ensure the normal operation of fuel cells, it is necessary to ensure the removal of water and heat formed as a result of the reaction. Another limiting factor is the relatively high cost of liquid hydrogen and oxygen, the complexity of their storage.
Radioisotope energy sources
Radioisotope energy sources are mainly used in the following cases:
High flight duration;
Missions to the outer regions of the solar system, where the flux of solar radiation is low;
Reconnaissance satellites with side-scan radar, due to low orbits, cannot use solar panels, but have a high demand for energy.
1.2 Automation of the power supply system
It includes devices for controlling the operation of the power plant, as well as monitoring its parameters. Typical tasks are: maintaining within the specified ranges of system parameters: voltage, temperature, pressure, switching operating modes, for example, switching to a backup power source; failure recognition, emergency protection of power supplies in particular by current; issuing information about the state of the system for telemetry and to the cosmonauts' console. In some cases, it is possible to switch from automatic to manual control either from the cosmonauts' console or by commands from the ground control center.
Similar information.
Image copyright SPL
Space missions lasting several decades - or even longer - will require a new generation of power supplies. The browser decided to figure out what options the designers have.
The power system is a vital component of a spacecraft. These systems must be extremely reliable and designed to work in harsh conditions.
Modern complex devices require more and more energy - what is the future of their power sources?
The average modern smartphone can barely last a day on a single charge. And the Voyager probe, launched 38 years ago, is still transmitting signals to Earth, having already left the solar system.
The Voyager computers are capable of 81,000 operations per second - but the smartphone's processor is seven thousand times faster.
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When designing a phone, of course, it is assumed that it will be regularly recharged and is unlikely to be several million kilometers from the nearest outlet.
It will not work to charge the battery of a spacecraft, which, according to the plan, should be one hundred million kilometers from a current source - it needs to be able to either carry batteries of sufficient capacity on board to work for decades, or generate electricity on its own.
To solve such a design problem, it turns out, is quite difficult.
Some on-board devices need electricity only intermittently, but others need to run constantly.
Receivers and transmitters must always be turned on, and in a manned flight or on a manned space station, also life support and lighting systems.
Image copyright NASA Image caption The engines of the Voyagers are not the most modern, but they have successfully served for 38 years.Dr. Rao Surampudi leads the Energy Technology Program at the Jet Propulsion Laboratory at the California Institute of Technology in the United States. For more than 30 years, he has been developing power systems for various NASA vehicles.
According to him, the energy system usually accounts for about 30% of the total mass of the spacecraft. It solves three main tasks:
- power generation
- electricity storage
- electricity distribution
All these parts of the system are vital to the operation of the apparatus. They should be lightweight, durable and have a high "energy density" - that is, to generate a lot of energy with a fairly small volume.
In addition, they must be reliable, since it is very impractical to send a person into space to fix breakdowns.
The system must not only generate enough power for all needs, but also to do so throughout the entire flight - and it can last for decades, and in the future, perhaps centuries.
"The estimated lifetime should be long - if something breaks, there will be no one to fix it," says Surampudi. under 30".
Image copyright NASA Image caption NASA's asteroid deflection mission will use a new type of solar power that is more efficient and more durable than its predecessorsSpacecraft power systems are under very specific conditions - they must remain operational in the absence of gravity, in a vacuum, under the influence of very intense radiation (which would disable most conventional electronic devices) and extreme temperatures.
“If you land on Venus, then it will be 460 degrees overboard,” says the specialist. “And when landing on Jupiter, the temperature will be minus 150.”
Vehicles headed for the center of the solar system have no shortage of energy harvested by their photovoltaic panels.
These panels look not much different from the solar panels that are installed on the roofs of residential buildings, but at the same time they work with much higher efficiency.
It is very hot near the Sun and photovoltaic panels can overheat. To avoid this, the panels are turned away from the Sun.
In planetary orbit, photovoltaic panels are less efficient: they generate less energy, since from time to time they are fenced off from the Sun by the planet itself. In such situations, a reliable energy storage system is needed.
Atomic Solution
Such a system can be built on the basis of nickel-hydrogen batteries that can withstand more than 50,000 charge cycles and work for more than 15 years.
Unlike conventional batteries, which do not work in space, these batteries are sealed and can function normally in a vacuum.
As you move away from the Sun, the level of solar radiation naturally decreases: for the Earth it is 1374 watts per square meter, for Jupiter it is 50, and for Pluto it is only one watt per square meter.
Therefore, if the device flies beyond the orbit of Jupiter, then atomic power systems are used on it.
The most common of these is the radioisotope thermoelectric generator (RTG) used on the Voyager and Cassini probes and on the Curiosity rover.
Image copyright NASA Image caption An improved radioisotope Stirling generator is being considered as one of the possible power sources for long missions.There are no moving parts in these power supplies. They generate energy through the decay of radioactive isotopes such as plutonium. Their service life exceeds 30 years.
If an RTG cannot be used (for example, if a shield too massive for flight is needed to protect the crew from radiation), and photovoltaic panels are not suitable due to the too large distance from the Sun, then fuel cells can be used.
Hydrogen-oxygen fuel cells were used in the US Gemini and Apollo space programs. Such cells cannot be recharged, but they release a lot of energy, and the by-product of this process is water, which the crew can then drink.
NASA and the Jet Propulsion Laboratory are working to create more powerful, energy-intensive and compact systems with a high working resource.
But new spacecraft need more and more energy: their on-board systems are constantly becoming more complex and consume a lot of electricity.
For long flights, nuclear-electric propulsion may be used
This is especially true for ships that use an electric drive - for example, ion propulsion, first used on the Deep Space 1 probe in 1998 and has since become widely adopted.
Electric motors typically operate by electrically ejecting fuel at high speed, but there are also those that accelerate the apparatus through electrodynamic interaction with magnetic fields planets.
Most terrestrial energy systems are not capable of operating in space. Therefore, any new circuit before being installed on a spacecraft undergoes a series of serious tests.
NASA laboratories are recreating the harsh conditions in which the new device will have to function: it is irradiated with radiation and subjected to extreme temperature changes.
To new frontiers
It is possible that improved radioisotope Stirling generators will be used in future flights. They operate on a principle similar to RTGs, but are much more efficient.
In addition, they can be made very small - although this further complicates the design.
New batteries are also being created for NASA's planned flight to Europa, one of Jupiter's moons. They will be able to work at temperatures from -80 to -100 degrees.
And the new lithium-ion batteries that designers are currently working on will have twice the capacity of the current ones. With their help, astronauts can, for example, spend twice as much time on the lunar surface before returning to the ship to recharge.
Image copyright SPL Image caption To provide energy to such settlements, most likely, new types of fuel will be required.New solar panels are also being designed that could efficiently collect energy in low light and low temperatures - this will allow devices on photovoltaic panels to fly farther from the Sun.
At some stage, NASA intends to establish a permanent base on Mars - and possibly on more distant planets.
The energy systems of such settlements must be much more powerful than those used in space today, and designed for much longer operation.
There is a lot of helium-3 on the Moon - this isotope is rare on Earth and is an ideal fuel for thermonuclear power plants. However, it has not yet been possible to achieve sufficient stability of thermonuclear fusion in order to use this energy source in spacecraft.
In addition, the thermonuclear reactors that exist today occupy the area of an aircraft hangar, and in this form it is impossible to use them for space flights.
Is it possible to use conventional nuclear reactors - especially in vehicles with electric propulsion and in planned missions to the Moon and Mars?
In this case, the colony will not have to maintain a separate source of electricity - the ship's reactor can act in its role.
For long flights, nuclear-electric propulsion may be used.
"The Asteroid Deflection Mission vehicle needs large solar panels to have enough electrical power to maneuver around the asteroid," says Surampudi.
However, we are unlikely to see nuclear-powered spacecraft anytime soon.
"This technology is not well developed yet. We must be absolutely sure of its safety before launching such a device into space," the specialist explains.
Further rigorous testing is needed to ensure that the reactor can withstand the rigors of spaceflight.
All of these promising energy systems will allow spacecraft to last longer and fly farther - but they are still in the early stages of development.
When the tests are successfully completed, such systems will become a mandatory component of flights to Mars - and beyond.
- You can read it on the website.
Development of a competitive space technology requires a transition to new types of batteries that meet the requirements of power supply systems for advanced spacecraft.
Today, spacecraft are used to organize communication systems, navigation, television, study weather conditions and natural resources of the Earth, exploration and study of deep space.
One of the main conditions for such devices is precise orientation in space and correction of motion parameters. This significantly increases the requirements for the power supply system of the apparatus. The problems of the power supply of spacecraft, and, first of all, developments to determine new sources of electricity, are of paramount importance at the world level.
Currently, the main sources of electricity for spacecraft are solar and storage batteries.
Solar batteries have reached the physical limit in terms of their characteristics. Their further improvement is possible with the use of new materials, in particular, gallium arsenide. This will increase the power by 2-3 times solar battery or reduce its size.
Among batteries Nickel-hydrogen batteries are widely used today for spacecraft. However, the mass-energy characteristics of these batteries reached their maximum (70-80 W*h/kg). Their further improvement is very limited and, moreover, requires large financial costs.
In this regard, at present, the space technology market is actively introducing lithium-ion batteries(LIA).
The performance of lithium-ion batteries is much higher than other types of batteries with a similar life and the number of charge-discharge cycles. The specific energy of lithium-ion batteries can reach 130 or more Wh / kg, and the energy efficiency is 95%.
An important fact is that LIBs of the same standard size are able to operate safely under their parallel connection in groups, thus, it is easy to form lithium-ion batteries of various capacities.
One of the main differences between LIB and nickel-hydrogen batteries is the presence of electronic automation units that control and manage the charge-discharge process. They are also responsible for leveling the voltage imbalance of individual LIBs, and ensure the collection and preparation of telemetric information about the main parameters of the battery.
But still, the main advantage of lithium-ion batteries is considered to be weight reduction compared to traditional batteries. According to experts, the use of lithium-ion batteries on telecommunication satellites with a capacity of 15-20 kW will reduce the mass of batteries by 300 kg. Considering that the cost of launching 1 kg of payload into orbit is about 30 thousand dollars, this will significantly reduce financial costs.
One of the leading Russian developers similar storage batteries for space vehicles is OJSC Aviation Electronics and Communication Systems (AVEKS), which is part of KRET. The technological process of manufacturing lithium-ion batteries at the enterprise ensures high reliability and cost reduction.
