When the show debuted, it immediately attracted a devoted fanbase but unfortunately it did not draw a broad enough audience to count as a ratings success. Not helping matters was the fact that it was scheduled in the Sunday 7 PM EST timeslot which was typically used for family-friendly fare on ABC and NBC and that competed against ratings powerhouse
60 Minutes on CBS. Since the show was very expensive to produce (around $5 million per episode according to
IMDb), FOX ended up cancelling it after only one season. The network was still trying to establish itself, and
The X-Files was still a couple of years away from moving from cult status to Top 20 hit. Apparently execs decided that sticking with such an expensive series as
Space: Above and Beyond that was not delivering on the ratings side was not the right strategy at that time.
The final episode ended on somewhat of a cliffhanger, but since the producers had enough notice of the cancellation, they tried to wrap up the story as best they could. The original plan was for the show to follow a five-year arc, but sadly only one year was completed. Fans lobbied for the show, but were unable to convince FOX to keep it going for a second year (foreshadowing what we would later see with
Firefly)