Commander Koenig questions a mysterious, supposedly Earth man, voice over the radio: "Who won the World Series in 1998?" To which the reply came "The Boston Red Sox beating the St. Louis Cardinals 4-3." Not a bad prediction for 1976. They were only six years off. When that exact confrontation did occur, it was in 2004, with the Red Sox beating the Cardinals four games to zero, allowing the Red Sox to break Babe Ruth's "curse". In reality, the 1998 winners were the New York Yankees, who defeated the San Diego Padres four games to zero. The man (Dr. Logan) goes on to state that this was the Red Sox's last win before all competitive sports were banned in 2026.
Unused special effects shots of Texas City (as well as model shots of the Moonbase and the spaceship Satazius from The Last Enemy (1976)) were borrowed for a third season episode of Wonder Woman (1975) titled Time Bomb (1978).
The show's producers were aware of the illogicality of the Alphans answering the neutrino transmissions with their more primitive equipment (as well as receiving data from the stranded Alphans' wrist monitors), but in the book "The Making of Space: 1999" they're quoted as saying that "This is Science Fiction. You have to expect that in this type of show" (just as aliens typically speaking English).
After drinking some of Tony's beer, Maya changes into Mr. Hyde (including affecting Victorian clothing, demonstrating that she can even transform into a fictional character). Although suggested previously, this means that her shape-shifting includes her clothes, implying that (like other shifters such as the X-Men's Mystique) she actually walks around effectively naked, with any clothes being simulated by her powers (although it has been established that her transformations cannot exceed an hour). Also, it implies that her own culture has a lot in common with Earth's culture, especially given her choice of animal forms (doves, panthers, wolves).