At least better than the previous episode for sure. Inspired though from some British films, from directors such as Robeert Day ot Val Guest, where astronauts back to earth become not murderers but monsters. That said, I am not a scientist and I quite don't know if all those technicalities mentioned in this episode are true, authentic or not. But it is good, if you also consider the lame side of this series. Don't be too hard when you watch those stories. Only the last sentence of the episode seems to be too didactic for my taste. The most important is that I have notice some progress in this thirteen episodes TV show from the seventies.