If you've opened a fortune cookie, you've probably read an aphorism, like this one, 'The world may be your oyster, but that doesn't mean you'll get its pearl.' In just a few words this quote tells the reader a lesson about life, that you have nearly limitless possibilities, but not all of them lead to a great reward.
The exploration of Neptune has only begun with one spacecraft, Voyager 2 in 1989. Currently there are no approved future missions to visit the Neptunian system. NASA, ESA and also independent academic groups have proposed future scientific missions to visit Neptune.
Suffice it to say that as a result of those calculations, Neptune was discovered on September 23, 1846 by the astronomer Johann Galle and his student Heinrich d'Arrest, after only thirty minutes of searching the sky, within a degree of the position predicted by Urbain Le Verrier.