NASA engineers, once again, picked up on the Voyager 2's heartbeat signal.  After ten long days of silence, NASA is optimistic they can reestablish contact with the spacecraft in interstellar space billions of miles from the Earth.

The flight controllers working at the Jet Propulsion Laboratory (JPL) in California operate the spacecraft. When they sent a wrong command, the 1970s-style spacecraft reacted by turning its antenna away from Earth. The antenna is only 2% off-kilter.  And it severed contact on July 21.

“A series of planned commands sent to NASA’s Voyager 2 spacecraft July 21 inadvertently caused the antenna to point 2 degrees away from Earth,” NASA officials said in a July 28 statement. “As a result, Voyager 2 is currently unable to receive commands or transmit data back to Earth.”

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Heartbeat signal 

NASA has a global Deep Space Network of giant radio antennas. The network picked up a “heartbeat signal," meaning the 46-year-old craft is “alive and operating,” according to project manager Suzanne Dodd’s email Tuesday.

The news “buoyed our spirits,” Dodd said. Flight controllers at the JPL will now try to turn Voyager 2’s antenna back toward Earth.

“A bit like hearing the spacecraft’s ‘heartbeat,’ it confirms the spacecraft is still broadcasting, which engineers expected,” officials at JPL posted in a tweet on August 1. “Engineers will now try to send Voyager 2 a command to point itself back at Earth.”

The command may not adjust the antenna. Then, engineers will need to wait until October for an automatic spacecraft reset. 

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

Voyager 2 was launched into space in 1977, along with its identical twin rocket Voyager 1. Their mission was to explore the outer planets.

Still communicating without a glitch and working fine, Voyager 1 is now 15 billion miles (24 billion kilometers) from Earth. It is the most distant spacecraft sent by humans.

Voyager 2 trails its twin. Its location is 12 billion miles (19 billion kilometers) from Earth. And it takes more than 18 hours for signals to travel one way.