“Computer Affair” is episode twenty-one of season one of UFO.
Colonel Freeman is on MoonBase and has just finished what sounds like a regular monthly update when SID reports a possible UFO sighting. Interceptors are manned and ready and are launched when the UFO is confirmed. They fire, but miss, and SID reports the UFO is on a collision course with the Interceptors. Two are given new courses on time; the third is destroyed.
Freeman is reporting to Straker at SHADO Control; Straker knows what happened but wants to know why. Freeman can’t be sure, but it’s possible it was human error. A decision was made that could have worked but didn’t. Straker wants the two pilots, Waterman and Bradley, and Lt. Ellis to return to Earth. The UFO was lost but it’s known it landed somewhere in northern Canada and everything that flies is looking for it.
Freeman leaves the office later as the three from MoonBase arrive. Bradley, as Interceptor leader, accepts responsibility. Straker tells him that’s gallant, but out of line. He knows what happened and wants to know why. What went wrong?
The UFO was hiding in a lake and takes off, and SID detects it. It must have been damaged by the Interceptors and Sky 1 is detailed to go after it.
The three from MoonBase undergo testing and interviews in the Psycho-Analytic Department. Sky 1 hits but doesn’t destroy the UFO; it ends up crashlanding.
Straker wants Freeman to lead the team to go after the UFO and, if possible, capture the aliens alive. The computer makes recommendations about Bradley and Ellis that Straker agrees with, but it seems Freeman does not, and he makes his own decision on the matter to prove something.
There’s a bit of weirdness about this episode, considering where it is in the series, especially as Waterman has gone from commanding a Skydiver to being an Interceptor pilot, but that’s because it was the second one filmed.