This bug popped up in 2018 and I see a lot of people discussing things that ‘fixed’ it for them. Talk to the captain, talk to the navigator (with no command stations so he starts the mission), interact with the fleet control terminal, There is one note that indicates that there will be a mission in the log for you to send out a frigate, select that and the command terminal should work. (No indication that that worked for the requester though). One player said that the game gave the blueprints to them after a mission or two. Finally someone on steam shows using the save editor to add those to the known products, I’m on PS4, no save editor for me.
I don’t have a plan for what I’ll do in the game this weekend (the game was consuming my life, I locked it in a room and only let it out on weekends) so I can start a new game and see how the sequence works, and if I can break/fix it.