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 strictly as sporting equipment, and even baseball players didn't generally wear their caps off the field.  The general public didn't adopt baseball caps into casual fashion until the 1970s.