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Solar panels may refer to a number of different energy-generating devices; namely solar thermal energy panels, photovoltaic modules or sets of solar photovoltaic modules electrically connected together and mounted on a support. The latter of which is the solar panel that most people are referring to when thinking of adding solar panels to their residencies.
When multiple solar panels are connected together in a large network, the power they can generate is sufficient to run a vast amount of applications. To maximize their efficiency, solar panels are orientated towards the Sun.
Solar panels are widely used in spacecrafts, especially those sent into the inner solar system, e.g, Juno, Magellan, Mars Global Surveyor and the Mars Observer.
Solar Panel Technology
Photovoltaic cells in solar panels capture sunlights. Using semiconductors, the light is then converted into direct current electricity. On spacecraft, there is a tracking mechanism embedded into the solar panels to ensure that they are always facing the Sun regardless of where the spacecraft is positioned.
The main functions of solar panels on spacecraft are as follows:
- To power sensors, heating/cooling systems and telemeters
- To provide power for spacecraft propulsion
Solar panels are the most expensive subsystems on a spacecraft due to the materials used to produce them and the labor expenses associated with their design and production. Therefore it is very important to ensure that solar panels on spacecraft are sturdy, durable and able to withstand constant exposure to solar radiation and other space elements.
Gallium arsenide was coventionally used in solar cells. Nowadays, advanced multiband-gap cells with the capability of trapping the largest possible spectrum of light are being used. These cells are far more efficient than their gallium arsenide predecessors able to reach upwards of 30%.
In order to optimize their functionality, spacecrafts also have solar concentrators. Using Fresnel lenses designed to capture large amounts of sunlight, they concentrate it onto smaller spots on the solar panels. NASA's Deep Space 1 experimental spacecraft used solar concentrators with 720 lenses directing sunlight onto 3,600 solar cells. This allowed 2,500 W of power to be generated to run the spacecraft's engine.
Future of Solar Panels
Geoff Landis, from NASA's Glenn Research Center, envisages a future where spacecrafts are able to travelo beyond our solar system thanks to advanced solar cells. Being made from advanced thin films, future solar cells will be extremely lightweight and able to collect a great deal more solar power than current ones.
Chair of the US-based Institute for Ethics and Emerging Technologies, George Dvorsky, believes that it may be possible to construct a vast array of independent solar panels which orbit in a dense formation around the sun such that they could provide the Earth with more energy than we would ever need. However, for this concept to become a reality, Mercury would have to be destroyed!
Thanks to innovations with reneweable energy, solar panels are rapidly developing. With the advancement in materials and technology, scientists may be able to achieve as much if not more than the far-fetched ideas of Dvorsky.
Sources and Further Reading