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. However ...''


 * Why does the US satellite look exactly like the Russian satellite Sputnik?


 * Maybe that is why the agents were assigned to retrieve it.''