Theory:Doctor Who television discontinuity and plot holes/Delta and the Bannermen


 * By 1959, the idea of launching satellites shouldn't be a big secret anymore.
 * Perhaps this particular satellite was a spy satellite? The DVD production notes suggest that, perhaps in the Whoniverse the US launched its first satellite later than in the real world.


 * Why does the US satellite look exactly like the Russian satellite Sputnik?
 * Maybe that is why the agents were assigned to retrieve it


 * Why does eating alien food turn billy into a Chimeron? Shouldn't it poison him?
 * It wasn't just food. It was a special Jelly. Like Delta says, the change had never been undertaken before.


 * The nylon mesh baseball cap worn by Weismuller would not yet have been available in 1959. Baseball caps of that period were made of wool and/or cotton fabric.  Additionally, in 1959 baseball caps were not yet common casual headwear for adults; they were seen as sporting equipment, and even baseball players didn't generally wear their caps off the field.  The general public didn't adopt baseball caps until the 1970s.