Voyager 1 Space Probe

NASA's space probe Voyager 1 was launched on September 5, 1977. It is the farthest spacecraft from earth. As of April 24th 2021, it is at a distance of 22.8 billion Kilometers from sun. The current velocity is 38,000 MPH and it will not change. It will go forever. It still communicates with Deep Space Network (space communication centers based in US, Spain and Australia) .

Voyager 1 communications are expected to continue until 2025. The power will no longer be supplied by Radioisotope Thermoelectric Generator (radioactive decay of Plutonium generates heat and is used to generate electricity with no moving parts).

As of 2013, It takes about19 hours to send signals back to earth at the speed of light (for continuously changing distance and constant speed of light, one can calculate time for a signal to reach back to earth, it's not that easy I guess ).