Alternatively, the signal is a distress call from a lost astronaut or a failed mission. Or perhaps it's a corporate espionage angle, where a rival company is sending interference.
Add some tension: Maybe the message's countdown is a deadline for Earth to stop a certain activity, like pollution or weapon testing. Or it's the arrival time of something. The team works against time to decode the message and find a way to respond or prevent disaster. tweakskycom
I think I have a basic outline. Need to flesh out characters, conflict, and resolution. Maybe add some personal stakes for Alex—family issues, pressure from superiors, or a past connection to the project. Alternatively, the signal is a distress call from