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One of the primary methods of creating power in space is by solar panels. However upon reading more about silicon based solar panels I got to know how even small dust particles can ruin the whole system. In space however dust is highly abrasive which increases the cost of mantainance of these solar panels. My question (1st part): a new alternative to silicon based panels, namely perovskites doesn't pose this problem but currently this these solar panels are quite unstable. So which of these solar panels are more suitable for space. My question (2nd part): for energy storage of batteries is preferable option. However for large space colonies is a Thermal Energy Storage System system preferred over batteries? (Since the extra heat can be rejected to these systems and heat can also be take from these systems to maintain temperature) For both the questions, please suggest a better alternative.

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closed as too broad by Jan Doggen, peterh, Steve Linton, Nathan Tuggy, Jack Jun 8 '18 at 9:09

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ "I got to know how even small dust particles can ruin the whole system." What do you mean by this? Can you add a link to what you've read on that, and why "...perovskites doesn't pose this problem..."? Do you mean during use in space, or during the manufacturing process? $\endgroup$ – uhoh Apr 14 '18 at 12:57
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    $\begingroup$ Is this not a solved problem? RTG, (small), or 'real' fission reactors, (large)? $\endgroup$ – Martin James Apr 20 '18 at 12:27
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    $\begingroup$ You should probably ask two separate questions, since they are only loosely related. $\endgroup$ – Antzi May 9 '18 at 2:01
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I'll address the 1st part of your question first. This is a much more complex issue than the question implies. Asking, "...which of these solar panels are more suitable for space?" is similar to asking, "What type of house is best for living on Earth?" The best type of house depends on where on Earth it will be! Similarly, the best type of solar cell depends on where in space it will be providing power.

The "where?" question has to do with the environment the cells will operate in. The environmental conditions of principal interest to power system engineers are sunlight intensity, temperature, and radiation. If the panels will operate in a region of high-velocity dust particles, that dust can influence the array design as well.

Sunlight intensity has a huge impact on array design. Solar cells have powered spacecraft at heliocentric distances all the way from Mercury (and even a bit closer, to ~0.3 AU) to Jupiter (~5.2 AU), for a factor of ~300 difference in sunlight intensity. Different cell chemistries and structures (such as single-junction or multi-junction) are better in different parts of that range.

Sunlight intensity is closely related to temperature: typically, in the absence of a relatively dense atmosphere or some kind of concentrator, higher solar intensities produce warmer arrays. This can be modified somewhat by controlling the thermal radiation from the arrays' back sides, either by insulating to keep them warmer or providing a high-emissivity radiating surface material to keep them cooler, or by off-pointing the arrays to keep them cooler by reducing the total sunlight power impinging on them. There are limits to keeping arrays warm without concentrators: insulate as you like on the back side, at 20 AU the arrays will not be at room temperature!

The combination of low solar intensity and low temperature is a problem of special interest to outer solar system exploration, with an assigned name: Low Intensity Low Temperature (this reference also treats radiation effects), "LILT". As intensity and temperature decrease, cell performance decreases, and the magnitude of the decrease differs significantly from cell to cell. In a given string of several cells (to get the voltage up to where it's needed), the worst performer limits the string performance. Hence the "selection program" approach used by Juno: you test each individual cell (Wow! Expensive!), and the bad performers are tossed out. Actually, those bad performers work just fine under "normal" intensity and temperature conditions, so they are sent back to the manufacturer for use in other, less demanding applications. Some chemistries, such as GaAs, do better than others under these conditions, especially the multi-junction types such as used on the Dawn spacecraft. If research produces a perovskite chemistry that is amenable to the multi-junction architecture, they might do well also.

Why not just use concentrators in the outer solar system, avoiding the LILT effects? Like spacecraft directional radio antennas, solar concentrators are "beamy": when pointed correctly, performance is great, but the performance drops dramatically as pointing errors increase. This is a bad situation for spacecraft emergencies: if you lose pointing control, you lose your main power source too, and the spacecraft's battery capacity limits the time you have to resolve the emergency and get those arrays back on sun-point. This risk has kept reliance on concentrators out of flight mission architectures to date, except for technology demonstrator missions such as NASA's Deep Space 1.

Radiation is also a concern in certain environments such as orbiting Jupiter. Particulate radiation causes lattice defects in the semiconductor, and these defects act as recombination centers for the electrons and holes, converting the energy that would have become usable cell output into heat instead. Cell chemistry influences this sensitivity, and in turn that sensitivity is influenced by the type and energy spectrum of the radiation. In the face of a high-radiation operating environment (such as Juno has, especially in the later orbits), power system designers opt for the cell chemistry best suited for the radiation environment.

In summary, the large range of environmental conditions encountered in the solar system make it very useful to have multiple solar cell chemistries and architectures available. No single chemistry and architecture is a "one size fits all" solution.

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  • $\begingroup$ Interesting answer! $\endgroup$ – uhoh Jun 8 '18 at 1:20
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Space dust poses a problem to solar panels not because it's abrasive, but because it arrives at a high enough speed to punch a hole in the solar panel. You can't solve that by going to a different material. You'd have to switch to a much heavier structure, with a transparent panel in front of the solar cells working as a Whipple shield.

Perovskite isn't a semiconductor, so I don't see how it can be used as a solar panel.

Thermal energy storage works if you have temperature differences you can exploit: the bigger the difference, the more efficient your storage becomes. For spacecraft, heat rejection is difficult and requires bulky radiators.

Colonies on a planet or moon might be able to use thermal energy storage, but traditionally, these systems require large amounts of a liquid to transport the heat so they might again be too bulky to be efficient.

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  • $\begingroup$ en.wikipedia.org/wiki/Perovskite_solar_cell Because it's not a semiconductor based on a crystal lattice with a very large size (like single crystal or large grain poly), it in fact might handle localized damage due to tiny impacts better (less leakage or recombinations) than a polycrystalline material. I don't know, but "You can't solve that by going to a different material" might not be 100% correct. $\endgroup$ – uhoh May 9 '18 at 1:59
  • $\begingroup$ Just as big of a problem, depending on your specific location in space, is particle radiation, which creates defects in the semiconductor junction. $\endgroup$ – Tristan May 10 '18 at 14:02

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