This is something that's been considered, particularly for doing things like terraforming Venus. There are these areas called Lagrange points[1] that provide a location where one can park a satellite where it'll remain stationary relative to the two-body system of interest. The point directly between the sun and earth is the L1 point and allows you to place a sunshade such that it'll always be directly between the sun and earth. It should be noted, however, that these points are generally not stable and so require some degree of station-keeping to remain viable long term.