As soon as man learned to put space vehicles into orbit, the question arose about the possibility of their long-term use. Correcting the orbit, transmitting data, supplying electricity to satellites and residential stations required energy. And it was possible to receive it around the clock outside the earth only from the sun. This is how solar panels appeared in space, the first of which were created almost simultaneously with the beginning of the exploration of near-earth space.
Creation and use of photovoltaic panels for extraterrestrial vehicles
The engineers of the USSR became the “pioneers” in the development of this type of photovoltaic system. For the Voskhod and Vostok spacecraft and the Salyut orbital stations, the heliopanels created by the group of physicist N.S. Lidorenko were used. He also made accurate mathematical calculations of the efficiency of solar cells in space for the technologies of that time.
At that time, the efficiency of silicon-based cells barely reached 8-10%, but the design of the modules was highly reliable. The basic ideas and technological solutions of Soviet scientists underlie the current space photovoltaics as well.
Over the past 60 years, similar panels have been equipped with:
- more than 250 interplanetary stations (the only exception is 4 spacecraft launched into deep space and receiving energy from radioactive elements);
- over 3,300 satellites, including Elon Musk’s rapidly growing StarLink group;
- 72 lunar rovers, long-term operation of which required a constant supply of energy;
- 14 rovers, including an American and Chinese one, heading towards Mars in 2020.
Advantages and disadvantages of solar panels in space
Like any other high-tech equipment, PV panels for extraterrestrial space have advantages and disadvantages.
Pros:
- outside the earth there is no atmosphere, rain and clouds, the flow of solar radiation is constant, and therefore the panels generate current around the clock (with the exception of devices on the Moon and Mars);
- insolation in airless space is much higher, which increases the efficiency of using solar cells in space;
- the efficiency of space photovoltaics reaches 40-45%.
Minuses:
- due to huge temperature changes, micro meteorites and hard cosmic radiation, the panels degrade faster;
- solar batteries for space cost a lot by themselves, and their delivery into orbit requires an additional 2-2.5 thousand dollars for each kilogram of mass;
- unfavorable operating conditions force the use of multi-level protection for all elements of the modules, which makes them even more expensive and massive.
However, there is still no worthy alternative to solar panels outside the planet to perform the same tasks.
Space SES of the future
Another incredibly promising area of application of solar cells in space is the creation of large-scale orbital power plants in the near future. The reason for this interest in this project is as follows:
- The power of the radiation flux of our luminary, directed towards the earth, is thousands of times greater than all the energy consumed by humanity.
- The placement of any number of solar panels in orbit is not limited by anything. Theoretically, they can form huge fields with an area of millions of square kilometers.
- Energy will be generated in a 365/24/7 mode, with the possibility of transmitting it to the ground via a microwave beam.
At the moment, the only obstacle to the implementation of such a project is its prohibitive cost. However, in the future, with the advent of technologies such as the “space elevator”, the cost of launching cargo into orbit will become about 1000 times cheaper. And then the creation of such “SES of the future” can turn into reality.
Which solar cells in space are most efficient?
Initially, space panels were created on the basis of monocrystalline silicon. In addition to poor performance, they also had a number of other disadvantages.
Today, photovoltaics for extraterrestrial space uses exclusively thin-film technologies. The cells are based on composites of rare-earth elements of the CIGS type, which are alternating layers of sulfides of gallium, indium, and other rare metals.
This makes it possible to dramatically increase the absorption of photons of different wavelengths, which increases the efficiency and durability of the system by several times.
Such solar panels are more expensive, but in the space industry, price is far from the most important role.