Yeah, orbital mirrors essentially expand the radius of Mercury, increasing the sunlight available. Terrestrial mirrors would ensure that light makes it from the sunward side to the dark side of the planet.
Also, the kind of satellites that aren't much more than mirrors, even with today's knowledge, they can be designed to change their profile/surface and thus reduce the absorption of the incident radiation, if they'd had to cross the space between the sun and the sunlight collector areas.
Also, the kind of satellites that aren't much more than mirrors, even with today's knowledge, they can be designed to change their profile/surface and thus reduce the absorption of the incident radiation, if they'd had to cross the space between the sun and the sunlight collector areas.