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 the two gas giants Jupiter and Saturn and the ice giants, Uranus and Neptune, 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. 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 1 was moving with a velocity of , or 17 km/s, relative to the Sun, and was from the Sun reaching a distance of from Earth as of February 10, 2022. On 25 August 2012, data from Voyager 1 indicated that it had entered interstellar space. , Voyager 2 was moving with a velocity of , or 15 km/s, relative to the Sun, and was from the Sun reaching a distance of 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