According to the
wikipedia, it was suggested that "the quotation was taken from a White House booklet published in 1958. The Introduction to Outer Space, produced in an effort to garner support for a national space program in the wake of the Sputnik flight, read on its first page:
The first of these factors is the compelling urge of man to explore and to discover, the thrust of curiosity that leads men to try to go where no one has gone before. Most of the surface of the earth has now been explored and men now turn on the exploration of outer space as their next objective."
After that, the quotation was made famous by Star Treck series.
Is that it?