After several days of silence, NASA received communication from the billions of miles away Voyager 2 spacecraft.

Project manager Suzanne Dodd said in an email on Tuesday that NASA's Deep Space Network, a vast network of radio antennae, detected a "heartbeat signal", indicating that the 46-year-old craft is still alive and functional. 

Dodd remarked that the news "buoyed our spirits." The antenna of Voyager 2 will now be turned back toward Earth by flight controllers at the Jet Propulsion Laboratory in California. 

They will have to wait until October for an automated spacecraft reset if the command doesn't work, which controllers doubt will happen. 

"That is a long time to wait, so we’ll try sending up commands several times" before then, Dodd said. 

Nearly two weeks ago, a mistaken command from the flight controllers caused the spacecraft's antenna to tilt away from Earth, breaking contact.

In an effort to study the outer planets, Voyager 2 and its identical twin, Voyager 1, were launched into space in 1977.

Voyager 1 is now the most distant spacecraft and is still communicating and functioning normally at a distance of 15 billion miles (24 billion kilometers) from Earth. 

At a distance of more than 12 billion miles (19 billion kilometers) from Earth, Voyager 2 is following its twin in interstellar space. At that distance, more than 18 hours are needed for a signal to travel one way.

NASA loses contact with Voyager 2

In the past few hours, NASA's Voyager 2 spacecraft, which has been journeying through interstellar space and holds the title of the farthest human-made object from Earth, lost contact with mission control after an accidental transmission of a faulty command more than a week ago.

Voyager 2 made significant discoveries during its journey, including finding a new moon around Jupiter, ten moons around Uranus, and five moons around Neptune. It remains the only spacecraft to have closely studied all four giant planets of our solar system.