The solar panels were rolled up inside Discovery. The small golden tubes represent these. They folded outwards, and then unrolled to reveal the panels within.
The flaps on the wings are used to steer Space Shuttle as it's gliding in the atmosphere. In space they use small nozzles that are in front and in the back of the shuttle(here represented by opened hollow studs). They basicly shoot small burst of gas in specific direction depending what pilot does and it changes the orientation of the shuttle.
Fun fact about the Hubble's solar panels: the real telescope's original panels also had that same warping issue. (Those solar panels were eventually replaced with smaller ones that are rigid, so they don't warp.) So this set has that extra bit of accuracy, even if it's unintentional.
If there is one thing I've learn from my last ideas set, it's that you never open every bag at the same time. The amount of empty bags and pieces that looks similar is too much even for me. Also, that model looks sooo good! It's amazing that set this good is possible to be released at somewhat affordable price. The amount of details and overall finish is pretty good^^ That wing play function feels to me a bit pointless, but to some it may be fun. Retractable wheels is nice touch as well, especially for people who want to keep it on a shelf that may be too small for a stand. As for solar panels, those gold tubes that you switch panels for are just meant to represent folded panels. I don't exactly know how, but they're able to deploy and be retracted. You can easily find pictures of hubble telescope being deployied, and there are pictures with panels both folded and ready to work. With international space station Lego used plastic Flag 7 x 3 with Rod piece for solar panels. here it would... Maybe it could work, but it would look kinda cheap, since that would take away a lot of detail for telescope. I believe that Lego went with best option they had available.
This set is between micro and minifig scale. The SaturnV at 1:110 is micro while this is 1:70. I believe minifig scale is around the 1:46 scale. They considered minifigs but they didnt add much to the set as the scales werent right
I'm pretty sure a transparent stand would have been more offensive, than the black one inside the shuttle, and the gold would have looked cheap in big amounts. anyway, it was an awesome review on an awesome set
