NASA’s Voyager 1 is the most-distant man-made object in space and is more than 24 billion kilometres away from us. But the first spacecraft to cross into interstellar space is not doing well and its days seem numbered as it is sending back incoherent messages to mission controllers at the space agency.

“It basically stopped talking to us in a coherent manner,” said Suzanne Dodd of NASA’s Jet Propulsion Laboratory to NPR. Dodd has been the project manager for the Voyager interstellar mission since 2010.

Voyager 1 and its sibling Voyager 2 have been on their journey for more than 40 years since they launched in 1977. They are both more than 130 times farther away from Earth than our planet is from the Sun. The two spacecraft were initially on a four-year mission to study Jupiter, Saturn and the larger moons of the two planets over a period of five years. This means that they outlasted their original mission lifespan by more than 35 years.