Boston Sunday Globe

Interstell­ar ‘shout’ restores NASA contact with lost Voyager 2

- By Ellen Francis

NASA’s Voyager 2 was lost in space because of a mixed signal, but a command dubbed an interstell­ar “shout” and beamed across billions of miles has restored contact with the spacecraft after two weeks of silence.

Voyager 2, which left Earth nearly 46 years ago, stopped receiving or transmitti­ng communicat­ions in July, when controller­s accidental­ly sent a command that shifted its antenna 2 degrees away from Earth.

This past week, NASA’s Deep Space Network, which consists of giant radio antennas around the world, picked up a carrier signal from the spacecraft — or what the mission team likened to a “heartbeat” that was too faint to pinpoint the probe but confirmed it was still operating, the US space agency said.

So engineers tried to send the spacecraft a command to orient itself back at Earth, and they used the highest-powered transmitte­r at NASA’s huge dish in the Australian capital, Canberra, according to NASA’s Jet Propulsion Laboratory, which manages the Voyager missions.

It may have been a long shot, but they heard back. “We shouted 12.3 billion miles into interstell­ar space, instructin­g it to turn its antenna back to Earth,” the laboratory said Friday. “And after 37 hours, we found out it worked!”

NASA said its Deep Space Network facility in Canberra “sent the equivalent of an interstell­ar ‘shout’” to Voyager 2 — a round-trip communicat­ion that required some 18.5 hours each way, for the command to reach the probe and to hear back.

“The spacecraft began returning science and telemetry data, indicating it is operating normally and that it remains on its expected trajectory,” NASA said in its latest update.

“I melted in the chair,” project manager Suzanne Dodd told the Associated Press. The twoweek silence was thought to be the longest NASA went without hearing from Voyager 2.

If its efforts had not succeeded, the team would have had to wait for the 46-year-old probe to automatica­lly reset its direction in October.

Voyager 2, whose launch anniversar­y is this month, took off in 1977 to sail across the solar system and in 2018 entered interstell­ar space, the region between the sun’s heliospher­e and the astrospher­es of other stars. It is the only spacecraft ever to fly by Neptune and Uranus, while its twin, Voyager 1, now nearly 15 billion miles away, is the most distant spacecraft from Earth.

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