Reflective panels are still effective in absorbing solar heat. The heat increase is about 10%, up from about 20% at the start. However, long-term use of reflectors will expose you to many problems. For example, the reflectors almost lose their function after dust accumulation and the wind resistance of the reflectors is too low. With the increase in the technology level of glass vacuum tubes and the improvement of water tank insulation technology, it is enough to ensure that users have hot water under normal lighting. Reflective panels can only add icing on the cake in terms of heat gain and cannot. provide timely help, so they were canceled by the general public.
If the general conditions are respected, the lunar satellite is 384,400 kilometers from the earth and the reflective zone of the ground panelarea is 1 square meter. I made theoretical calculations on astronomical forums and with enthusiasts. Considering only the diffuse reflection, its brightness is around 18th magnitude, which means you need a 1.5 meter diameter telescope to observe it. If there is specular reflection, the brightness will not be as high as above:
Thus, to make the lunar satellite visible from earth, there are several possibilities:
Make the size is bigger, it gets bigger and bigger and the diameter is increased up to 250 times the current diameter, which is 250 meters in diameter. The brightness is sufficient for observation on earth to detect it.
The brightness of the sun increases, the distance between the sun and the earth decreases, and the distance between the earth and the moon decreases. These things are easy to understand, so I won't explain them in detail. .
It's more interesting. While maintainingant the intensity of sunlight, reducing the diameter of the sun reduces the divergence of the light reflected by the mirror.
As for the specific calculated values, this is a pretty interesting calculation problem, and maybe it can be entered into the Astronomy Olympiad~ But I won't do the specific calculations here.