When working on a project, it is often useful to predict what will happen in the future, 5 or 10 years from now. Past data is needed in order to extrapolate them and make accurate predictions. How can I manage to get the area density of spatial solar panels from year 1970? This is used to calculate how much it costs to bring a square meter to orbit.
I did a search using these keywords: solar panel spacecraft "specific power"
At the start of the space age, solar arrays produced about 15W/kg and the cells were about 10% efficient.