"Interstellar shout" reestablishes contact with Voyager 2

"Interstellar shout" reestablishes contact with Voyager 2
Artist's concept of Voyager 2
Artist's concept of Voyager 2
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Artist's concept of Voyager 2
Artist's concept of Voyager 2

In a dramatic bit of improvisation, NASA' Jet Propulsion Laboratory (JPL) in Pasadena, California, has managed to reestablish communications with the Voyager 2 spacecraft 12.3 billion miles (19.9 billion km) from Earth after losing contact on July 21.

On August 4, 2023, NASA engineers managed to make contact with the Voyager 2 robotic probe even though previous estimates were that this would not be possible until October 15. Contact was lost on July 21 after a series of commands sent included an error that caused the spacecraft's antenna to point about two degrees away from Earth – a small shift that still managed to prevent the craft from maintaining radio contact.

The hope was that everything aboard Voyager 2 would continue to function normally without guidance from Earth until a preset program would make the probe realign itself on Earth on October 15. Since two and a half months is a long time to keep one's fingers crossed that something wouldn't go wrong, Mission Control decided to take some active measures.

Partial success came on August 1 when NASA's Deep Space Network (DSN) facility in Canberra, Australia, picked up the radio carrier wave from Voyager 2. This "heartbeat" told the space agency's engineers that the craft was still operational and that the deviation from the communications beam was a very slight one.

Since Voyager 2's 20-W radio signal from the edge of the solar system is 1,000 times weaker than that of a conventional FM transmitter and can still be picked up by the DSN while off beam, the engineers reasoned that it might be possible to send a much more powerful signal from the DSN that Voyager could not ignore.

This "interstellar shout" was easy enough to set up, but putting it into practice took some patience because a one-way radio signal to Voyager 2 takes 18.5 hours to reach its destination and another 18.5 hours for a reply. That is a very nerve-wracking 37 hours.

Fortunately, on August 2, 2023 at 12:29 am EDT, Voyager 2 began returning science and telemetry data. NASA says that the probe is functioning normally and is still on trajectory as it hurtles into interstellar space, never to return.

Source: NASA

Coolest news I've heard today. Kudos NASA! One day, in a galaxy far, far away, another civilization will intercept our visitor and marvel at how this antique crossed the universe.
I haven't done geometry in years, but it seems a 2 degree error at 12.3 billion miles comes out to more than 400 million miles.
David Ingram
It's good to hear it wasn't rear ended or stuck in traffic. I'm often amazed how some of our tech lasts way beyond the expectations. I've found 1940s electrical wiring and devices still working as designed. Sometimes early programmable devices are scrapped just because there is no one left who can operate or troubleshoot them.
"...a series of commands sent included an error that caused the spacecraft's antenna to point about two degrees away from Earth – a small shift..."

A "small shift"? Not when you're well over a billion miles away.
"Interstellar" is a bit of a stretch.
Captain Obvious
That story reminded me of a similar problem that we solved around 1973 at the Air Force Research Lab. I was running a test in an anechoic chamber with 100 KW or so at 450 MHz when the request came in to borrow our amplifier to shout out to a satellite that had gone 'deaf'. We piped the output into an antenna up on the roof and sucessfully woke up the bird.
Never, ever underestimate the Isley Brothers!
So apparently 'an error' was transmitted to the spacecraft. How can this happen? Is NASA short staffed? Doesn't every instruction get double checked before transmission?
@David Ingram, much like how a huge part of America’s banking and major infrastructure systems are written in COBOL, but people who can interpret the code to maintain, correct, and update it are becoming as rare as WWII veterans.
@Kpar, 2% IS a relatively small shift. It’s only when you follow that tiny angle out to such a great distance (12.3 BILLION miles!) that it has such a huge impact.
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