Any derelict ships you discover count as discovery data and are also subject to first discoveries.. as are solving them.
FD could implement these as explorer missions too.. regularly.. eg give an approximate direction the ship was headed in, and hasn't been heard from in some months, need active explorers to mount an expedition to find said ship and recover information regarding its whereabouts and crew status. You never know? you might (with repair drones) be able to make their ship flyable again and allow them to return home giving you even bigger bonuses for the mission.
You did see "Event Horizon", right?