02:14 - Source: CNN Business
How NASA keeps its 46-year-old Voyager spacecraft going

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Using a long-shot “shout” maneuver, the Voyager mission team at NASA has reestablished communication with Voyager 2 after losing contact with the spacecraft, which has been operating for nearly 46 years.

“At 12:29 a.m. EDT on Aug. 4, the spacecraft began returning science and telemetry data, indicating it is operating normally and that it remains on its expected trajectory,” according to an update shared by the space agency.

Commands sent to Voyager 2 on July 21 accidentally caused the spacecraft’s antenna to point 2 degrees away from Earth. The miniscule shift meant that Voyager 2 couldn’t receive any commands from mission control or send data back to Earth from its location more than 12.3 billion miles (19.9 billion kilometers) away in interstellar space.

Earlier this week, the mission team was pleasantly surprised to be able to detect the “heartbeat” of Voyager 2, or the spacecraft’s “carrier signal” using the Deep Space Network, an international array of massive radio antennas that allows NASA to communicate with missions across the cosmos.

Each of the three giant dishes are equidistant, meaning that one is always in communication with different spacecraft as our planet rotates. One radio antenna is located at Goldstone near Barstow, California, the second near Madrid, and the third near Canberra, Australia.

After detecting the heartbeat, the team used the station in Canberra to send an interstellar “shout,” essentially an amplified radio signal, to Voyager 2 with commands instructing the spacecraft to reorient its antenna to face Earth.

Given the massive distance between Earth and Voyager 2, the team thought there was a “low probability” that the command would work, given that the antenna wasn’t oriented in a way to receive a radio signal, said Suzanne Dodd, Voyager’s project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California.

It takes about 18.5 hours for the signal to travel one way across the solar system to the spacecraft. Overall, it took 37 hours for mission controllers to learn that the shout worked.

Had the Earth-based signals not reached Voyager 2, the spacecraft is already programmed to reorient itself multiple times a year to keep its antenna pointing in our planet’s direction. The next reset was already scheduled for October 15. But the team didn’t want to wait that long, Dodd said.

It’s not the first time that the aging twin probes — Voyager 1 and Voyager 2, both launched in 1977 — have experienced issues. As these “senior citizens” continue exploring the cosmos, the team has slowly turned off instruments to conserve power and extend their missions. Along the way, both spacecraft have encountered unexpected issues and dropouts, including a seven-month period where Voyager 2 and the Deep Space Network couldn’t communicate in 2020.

Voyager 1, which is nearly 15 billion miles (24 billion kilometers) from Earth, continues to operate as expected and communicate with the Deep Space Network.

Both probes are in interstellar space and the only spacecraft to operate beyond the heliosphere, the sun’s bubble of magnetic fields and particles that extends well beyond the orbit of Pluto, collecting valuable data as they explore uncharted territory.