In the writers and directors' guide for the series, written by Gene Roddenberry prior to the first season, Romulans were covered by one of the main writing rules which stated "No stories about warfare with Klingons and Romulans and no stories with Vulcans. We are determined not to copy ourselves and believe there must be other interesting aliens in a galaxy filled with billions of stars and planets." Following the perceived failure of the Ferengi as the main villains of TNG by the production staff, the Romulans became the main villains during the early years of the series. This was in addition to the Borg, who were originally developed as an insectoid race for this episode but became a race of cyborgs by the time they first appeared in Q Who (1989).
The cryonics satellite was identified only as "an ancient capsule" or "space module" in the episode. Both the 'Star Trek Encyclopedia' and the 'Star Trek: The Next Generation Companion' mention that the name SS Birdseye was inscribed on the hull. The topmost segment of the satellite was labeled with the registry or identification number 4077, one of the many references to M*A*S*H (1972). "Birdseye Seafood, Inc." was one of the first brands of frozen food, making the satellite name an inside joke.
When Claire Raymond searches for her family members with Counsellor Troi, the names on the screen are the names of the series' main crew actors.
Maurice Hurley had something more in mind with this episode. The attacks the Romulans complain about dangled as an unresolved plot device for quite some time, but there was a plan: Hurley had meant this episode to compose part of a trilogy in which the Borg would be formally introduced. The opening episode of the second season further explored matters, including a possible alliance between the Federation and the Romulan Empire to counter the new threat. Such plans, however, were ruined by the 1988 Writers Guild of America strike. The Borg's introduction had to wait until Q Who (1989).
The subplot regarding the time-displaced characters was added at the last minute after the cliffhanger angles to the plot had to be scaled back. The subplot was based on a fan story written by Deborah McIntyre and Mona Clee.