Sputnik was the science payload - at that point the US were still saying it'd be years until orbit was reached.
Ironically, had it not been for the space race, we might have a more mature space program now, rather than one largely based on 1940s technology and engineering. They rushed to production and massively invested in a single model on both sides, rather than exploring options fully before commencing - similar applies to nuclear technology, insofar as thorium would have been the better tech, but was too late to the party to gain traction, never mind the weapon byproduct bit.