Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. A part of the Voyager program, it was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach gas giants Jupiter and Saturn but enabled further encounters with ice giants Uranus and Neptune. Voyager 2 remains the only spacecraft to have visited either of the ice giant planets. Voyager 2 was the fourth of five spacecraft to achieve Solar escape velocity, which allowed it to leave the Solar System.

Voyager 2 successfully fulfilled its primary mission of visiting the Jovian system in 1979, the Saturnian system in 1981, Uranian system in 1986, and the Neptunian system in 1989. The spacecraft is now in its extended mission of studying interstellar space. It has been operating for 44 years, 11 months and 18 days as of August 8, 2022 UTC [refresh]; as of July 31, 2022, it has reached a distance of 130.09 AU (19.461 billion km; 12.093 billion mi) from Earth.The probe entered interstellar space on November 5, 2018, at a distance of 122 AU (11.3 billion mi; 18.3 billion km) (about 16:58 light-hours) from the Sun and moving at a velocity of 15.341 km/s (34,320 mph) relative to the star. Voyager 2 has left the Sun's heliosphere and is traveling through the interstellar medium (ISM), a region of outer space beyond the influence of the Solar System, joining Voyager 1, which had reached the interstellar medium in 2012. Voyager 2 has begun to provide the first direct measurements of the density and temperature of the interstellar plasma.Voyager 2 remains in contact with Earth through the NASA Deep Space Network. In 2020, maintenance to the Deep Space Network cut outbound contact with the probe for eight months. Contact was reestablished on November 2, 2020, when a series of instructions was transmitted, subsequently executed, and relayed back with a successful communication message. On February 12, 2021, full communications with the probe were restored after a major antenna upgrade that took a year to complete. The DSS 43 communication antenna, which is solely responsible for communications with the probe, is located near Canberra, Australia.

The Voyager program is an American scientific program that employs two robotic interstellar probes, Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable alignment of Jupiter and Saturn, to fly near them while collecting data for transmission back to Earth. After launch the decision was taken to send Voyager 2 near Uranus and Neptune to collect data for transmission back to Earth.As of 2022, the Voyagers are still in operation past the outer boundary of the heliosphere in interstellar space. They collect and transmit useful data to Earth.

Voyager did things no one predicted, found scenes no one expected, and promises to outlive its inventors. Like a great painting or an abiding institution, it has acquired an existence of its own, a destiny beyond the grasp of its handlers.

As of 2022, Voyager 1 was moving with a velocity of 61,185 kilometers per hour (38,019 mph), or 17 km/s, relative to the Sun, and was 23,252,000,000 kilometers (1.4448×1010 mi) from the Sun reaching a distance of 155.8 AU (23.3 billion km; 14.5 billion mi) from Earth as of February 10, 2022. On 25 August 2012, data from Voyager 1 indicated that it had entered interstellar space.As of 2022, Voyager 2 was moving with a velocity of 55,335 kilometers per hour (34,384 mph), or 15 km/s, relative to the Sun, and was 19,350,000,000 kilometers (1.202×1010 mi) from the Sun reaching a distance of 130.1 AU (19.5 billion km; 12.1 billion mi) from Earth as of February 10, 2022. On 5 November 2019, data from Voyager 2 indicated that it also had entered interstellar space. On 4 November 2019, scientists reported that, on 5 November 2018, the Voyager 2 probe had officially reached the interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did Voyager 1 in 2012.Although the Voyagers have moved beyond the influence of the solar wind, they still have a long way to go before exiting the Solar System. NASA indicates "[I]f we define our solar system as the Sun and everything that primarily orbits the Sun, Voyager 1 will remain within the confines of the solar system until it emerges from the Oort cloud in another 14,000 to 28,000 years."Data and photographs collected by the Voyagers' cameras, magnetometers and other instruments revealed unknown details about each of the four giant planets and their moons. Close-up images from the spacecraft charted Jupiter's complex cloud forms, winds and storm systems and discovered volcanic activity on its moon Io. Saturn's rings were found to have enigmatic braids, kinks and spokes and to be accompanied by myriad "ringlets".

At Uranus, Voyager 2 discovered a substantial magnetic field around the planet and ten more moons. Its flyby of Neptune uncovered three rings and six hitherto unknown moons, a planetary magnetic field and complex, widely distributed auroras. As of 2021 Voyager 2 is the only spacecraft to have visited the ice giants Uranus and Neptune.

In August 2018, NASA confirmed, based on results by the New Horizons spacecraft, the existence of a "hydrogen wall" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.The Voyager spacecraft were built at the Jet Propulsion Laboratory in Southern California and funded by the National Aeronautics and Space Administration (NASA), which also financed their launches from Cape Canaveral, Florida, their tracking and everything else concerning the probes.

The cost of the original program was $865 million, with the later-added Voyager Interstellar Mission costing an extra $30 million.