For the UAs, yes the transmission was its purpose. Its purpose was to actively scan objects extrapolate a triangle mesh and report it back to Merope, searching for something (fulfills MB quote of different reason, transmission was the purpose, pointing back to different location for a different reason). The shell is a great example of a search ever expanding from its center point of Merope. Point back at Merope when nudged to reorient to source and stay on course. After the something was found, probes were sent to deliver a message, from triangle mesh to spectrogram sure seems more advanced (fulfills MB quote hints).
UPs purpose was to the deliver the message, provide a map and point of origination (pointing to Merope system for a different reason). Using the point of origination you can find the next piece of the puzzle. Both items related but not part of the same puzzle, also fulfills hints.
The image (map) provided isn't of a resolution to determine angles or math. It is a pictograph of where to start and end. The center image is of Merope's center star, lower right from origin goto center of system (star), top right is 2nd planet from star center, top left is 3rd orbiting body.. but I'm having trouble with the lower left. I'm thinking either something impacting or leaving.