system
Given the following post, respond as if you're commenting on Reddit:
human
Why are the solar panels on ISS different from the ones usually seen here on earth?
gpt
Space is a very harsh environment. Anything sent into space will likely need to be highly customized in order to function for any length of time.       
First is weight. Sending mass into space is expensive, so lowering weight is a high priority. The solar arrays for space missions are made much thinner than cheap-o solar cells you buy at ‘Solar Cells R Us’ and thus save on expensive fuel.        
Second is volume. Solar arrays need large surface areas in order to collect maximum sunlight. Large areas are incompatible with rockets moving at Mach 5+. So the solar arrays must fold into tiny packages to fit into cramped rockets.       
Third is radiation. Space, even within the Van Allen Belts, has lots of high-energy particles whizzing around that like to wreak havoc on materials, especially solid-state electronics such as solar cells.  Special cell materials are used, along with redundancy, to give the cells longer life in such a brutal environment.        
Fourth is physics.  The solar arrays must deploy remotely, since there is rarely someone present to do it manually. Deployment is usually a one-time action, so many cell arrays are basically designed using springs. Think of your umbrella that opens at the push of a button.    Getting them going is fairly straight-forward, but the lack of air in space means there is little damping like we get here on Earth. The cell array springs out, hit the end and much of that deployment energy bounces back from the end.  It keeps bouncing back and forth until is dissipate as (mostly) heat.  That means that the array support mechanism must be strong enough to handle that shock without transmitting the shock back into the satellite, space station, etc. it is connected to. Transmitting that shock can rattle other things loose and cause other problems.       
Fifth, more physics. As the ISS transitions from full sun (in front, on sides of Earth) to darkness (in Earth’s shadow), the drastic heats differences cause the solar array materials to expand and cools. All the components, including the cells themselves as well as the support structure, must be able to tolerate the expansion and contraction caused by the heating and cooling. This motion is usually exhibited as vibration. You’re no doubt familiar with this as the creaking sounds old houses make in the middle of the night as they cool.  These pops send shock waves down long panels, another factor the matrials and design must handle.      
These requirements, plus many more, require lots of custom design and test to make sure they don’t fail or worse, cause problems for other parts of the space station.