<P> Voyager 1 is a space probe launched by NASA on September 5, 1977 . Part of the Voyager program to study the outer Solar System, Voyager 1 launched 16 days after its twin, Voyager 2 . Having operated for 40 years, 7 months and 4 days as of April 9, 2018, the spacecraft still communicates with the Deep Space Network to receive routine commands and return data . At a distance of 141 AU (2.11 × 10 km), approximately 21 billion kilometers (13 billion miles) from the Sun as of January 2, 2018, it is the farthest spacecraft and man - made object from Earth . </P> <P> The probe's objectives included flybys of Jupiter, Saturn and Saturn's large moon, Titan . While the spacecraft's course could have been altered to include a Pluto encounter by forgoing the Titan flyby, exploration of the moon, which was known to have a substantial atmosphere, took priority . It studied the weather, magnetic fields and rings of the two planets and was the first probe to provide detailed images of their moons . </P> <P> After completing its primary mission with the flyby of Saturn on November 12, 1980, Voyager 1 became the third of five artificial objects to achieve the escape velocity that will allow them to leave the Solar System . On August 25, 2012, Voyager 1 became the first spacecraft to cross the heliopause and enter the interstellar medium . </P> <P> In a further testament to the robustness of Voyager 1, the Voyager team completed a successful test of the spacecraft's "trajectory correction maneuver" (TCM) thrusters on November 28, 2017 . The last time these backup thrusters were fired up was in November 1980 . Voyager project manager Suzanne Dodd anticipates that successful utilization of the TCM thrusters will extend the Voyager mission by an additional "two to three years". </P>

When did voyager 1 cross into interstellar space