The Exploration of Neptune started on August 25, 1989, when Voyager 2 became the first and so-far only spacecraft to visit the planet. Like the other gas giants, Neptune has no solid land on its surface so landing on Neptune would be impossible.

NASA is thinking to send another spacecraft known as the Neptune Orbiter to study more about Neptune; the spacecraft is planned to be probably launched on 2035. It would release atmospheric probes, and possibly release a Triton Lander. NASA has said the earliest possible launch date is 2030. Budget cuts may eliminate this proposal.