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 was launched 16 days after its twin, Voyager 2. Having operated for 41 years, 4 months and 6 days as of January 11, 2019, the spacecraft still communicates with the Deep Space Network to receive routine commands and to transmit data to Earth. At a distance of 145.11 astronomical units (2.1708×1010 km; 1.3489×1010 mi) (21.708 billion kilometers; 13.489 billion miles) from Earth as of January 1, 2019, it is the most distant human-made object from Earth.