For a while the Voyager 1 space craft was not able to communicate any data back to the earth. This month, however, NASA sent a different command and got a response back!
It is not fully functioning, but this gives NASA engineers something to work with.
Voyager 1 is about 15,000,000,000 miles from earth and it takes radio signals 22.5 hours to travel to the spacecraft. This means that a "conversation" between earth and Voyager 1 takes 45 hours per transmission.
Voyager 1 has been operating for 46 years.
https://www.scientificamerican.com/a...-1-spacecraft/