as the rescue truck approaches the communications tower you see a close up of Virgil wearing a white jacket but in the model shot he is in standard uniform without the coat as you can see its all blue with the yellow sash.
When Tim Casey is approaching Tracy Island, Jeff initially assumes it's "more of Tin-Tin's admirers". This is possibly in reference to Eddie Houseman's visit in "End of the Road", which originally aired after "Edge of Impact", so the events in this episode should have taken place after "End of the Road".
The Astronaut Observer newspaper at 10:20 is dated December 24, 1964. Its headlines were pasted over a mundane newspaper with a review of a Slough community theatre production.
Tim Casey is a colonel, but Scott refers to him as 'General' in one scene.