voyager

29 Articles

Welcome Back, Voyager

April 27, 2024 by 59 Comments

In what is probably the longest-distance tech support operation in history, the Voyager mission team succeeded in hacking their way around some defective memory and convincing their space probe to send sensor data back to earth again. And for the record, Voyager is a 46-year old system at a distance of now 24 billion kilometers, 22.5 light-hours, from the earth.

While the time delay that distance implies must have made for quite a tense couple days of waiting between sending the patch and finding out if it worked, the age of the computers onboard probably actually helped, in a strange way. Because the code is old-school machine language, one absolutely has to know all the memory addresses where each subroutine starts and ends. You don’t call a function like do_something(); but rather by loading an address in memory and jumping to it.

This means that the ground crew, in principle, knows where every instruction lives. If they also knew where all of the busted memory cells were, it would be a “simple” programming exercise to jump around the bad bits, and re-write all of the subroutine calls accordingly if larger chunks had to be moved. By “simple”, I of course mean “incredibly high stakes, and you’d better make sure you’ve got it right the first time.”

In a way, it’s a fantastic testament to simpler systems that they were able to patch their code around the memory holes. Think about trying to do this with a modern operating system that uses address space layout randomization, for instance. Of course, the purpose there is to make hacking directly on the memory harder, and that’s the opposite of what you’d want in a space probe.

Nonetheless, it’s a testament to careful work and clever software hacking that they managed to get Voyager back online. May she send for another 46 years!

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NASA’s Voyager 1 Resumes Sending Engineering Updates To Earth

April 22, 2024 by 29 Comments

After many tense months, it seems that thanks to a gaggle of brilliant engineering talent and a lucky break the Voyager 1 spacecraft is once more back in action. Confirmation came on April 20th, when Voyager 1 transmitted its first data since it fell silent on November 14 2023. As previously suspected, the issue was a defective memory chip in the flight data system (FDS), which among other things is responsible for preparing the data it receives from other systems before it is transmitted back to Earth. As at this point in time Voyager 1 is at an approximate 24 billion kilometers distance, this made for a few tense days for those involved.

The firmware patch that got sent over on April 18th contained an initial test to validate the theory, moving the code responsible for the engineering data packaging to a new spot in the FDS memory. If the theory was correct, this should mean that this time the correct data should be sent back from Voyager. Twice a 22.5 hour trip and change through Deep Space and back later on April 20th the team was ecstatic to see what they had hoped for.

With this initial test successful, the team can now move on to moving the remaining code away from the faulty memory after which regular science operations should resume, and giving the plucky spacecraft a new lease on life at the still tender age of 46.

Voyager 1 Issue Tracked Down To Defective Memory Chip

April 6, 2024 by 52 Comments

After more than forty-six years all of us are likely to feel the wear of time, and Voyager 1 is no different. Following months of harrowing troubleshooting as the far-flung spacecraft stopped returning sensible data, NASA engineers now feel confident that they have tracked down the cause for the problem: a single defective memory chip. Why this particular chip failed is unknown, but possibilities range from wear and tear to an energetic particle hitting it and disrupting its operation.

We’ve covered the Voyager 1 troubleshooting saga so far, with the initial garbled responses attributed to a range of systems, but narrowed down to the Flight Data Subsystem (FDS), which prepares data for transmission by the telemetry modulation unit (TMU). Based on a recent ‘poke’ command that returned a memory dump engineers concluded that the approximately 3% of corrupted data fit with this one memory chip, opening the possibility of a workaround.

Recently NASA engineers have also been working on patching up the firmware in both Voyager spacecraft, against the background of the dwindling energy produced by the radioisotope generators that have kept both spacecraft powered and warm, even in the cold, dark depths of Deep Space far beyond the light of our Sun.

NASA Engineers Poke Voyager 1 And Receive Memory Dump

March 16, 2024 by 59 Comments

For months, there has been a rising fear that we may have to say farewell to the Voyager 1 spacecraft after it began to send back garbled data. Now, in a sudden twist, Voyager 1 sent back a read-out of the Flight Data Subsystem (FDS) memory after a “poke” command, which both gives some hope that the spacecraft is in a better condition than feared while also allows engineers to dig through the returned memory read-out for clues. Although this data was not sent in the format that the FDS is supposed to use when it’s working correctly, it’s nevertheless readable.

It was previously suspected that the issue lay with the telemetry modulation unit (TMU), but has since been nailed down to the FDS itself.  This comes after NASA engineers have been updating the firmware on both spacecraft to extend their lifespan, but it’s too early to consider this as a possible reason. Now, as a result of the “poke” instruction – which commands the computer to try different sequences in its firmware in case part of it has been corrupted – engineers can compare it to previous downloads to hopefully figure out the cause behind the FDS problems and a possible solution.

Inspired by this news of the decoded memory download, Nadia Drake – daughter of Frank Drake – wrote about how it affects not only the engineers who have worked on the Voyager mission for the past decades but also her own thoughts about the two Voyager spacecraft. Not only do they form a lasting reminder of her father and so many of his colleagues, but the silence that would follow if we can no longer communicate with these spacecraft would be profound. Still, this new hope is better than the earlier news about this plucky little spaceship.

Thanks to [Mark Stevens] for the tip.

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Hackaday Links: March 10, 2024

March 10, 2024 by 17 Comments

We all know that we’re living in a surveillance state that would make Orwell himself shake his head, but it looks like at least one company in this space has gone a little rogue. According to reports, AI surveillance start-up Flock <<insert gratuitous “What the Flock?” joke here>> has installed at least 200 of its car-tracking cameras on public roads in South Carolina alone. That’s a serious whoopsie, especially since it’s illegal to install anything on state infrastructure without permission, which it appears Flock failed to obtain. South Carolina authorities are making a good show of being outraged about this, but it sort of rings hollow to us, especially since Flock now claims that 70% of the population (of the USA, we presume) is covered by their technology. Also, police departments across the country are in love with Flock’s service, which lets them accurately track the movements of potential suspects, which of course is everyone. No word on whether Flock will have to remove the rogue cameras, but we’re not holding our breath.

Continue reading “Hackaday Links: March 10, 2024” →

Flipped Bit Could Mark The End Of Voyager 1‘s Interstellar Mission

February 9, 2024 by 95 Comments

Sometimes it’s hard to read the tea leaves of what’s going on with high-profile space missions. Weighted down as they are with the need to be careful with taxpayer money and having so much national prestige on the line, space agencies are usually pretty cagey about what’s going on up there. But when project managers talk about needing a “miracle” to continue a project, you know things have gotten serious.

And so things now sit with Voyager 1, humanity’s most distant scientific outpost, currently careening away from Mother Earth at 17 kilometers every second and unable to transmit useful scientific or engineering data back to us across nearly a light-day of space. The problem with the 46-year-old spacecraft cropped up back in November, when Voyager started sending gibberish back to Earth. NASA publicly discussed the problem in December, initially blaming it on the telemetry modulation unit (TMU) that packages data from the remaining operable scientific instruments along with engineering data for transmission back to Earth. It appeared at the time that the TMU was not properly communicating with the flight data system (FDS), the main flight computer aboard the spacecraft.

Since then, flight controllers have determined that the problem lies within the one remaining FDS on board (the backup FDS failed back in 1981), most likely thanks to a single bit of corrupted memory. The Deep Space Network is still receiving carrier signals from Voyager, meaning its 3.7-meter high-gain antenna is still pointing back at Earth, so that’s encouraging. But with the corrupt memory, they’ve got no engineering data from the spacecraft to confirm their hypothesis.

The team has tried rebooting the FDS, to no avail. They’re currently evaluating a plan to send commands to put the spacecraft into a flight mode last used during its planetary fly-bys, in the hope that will yield some clues about where the memory is corrupted, if indeed it is. But without a simulator to test the changes, and with most of the engineers who originally built the spacecraft long gone now, the team is treading very carefully.

Voyager 1 is long past warranty, of course, and with an unparalleled record of discovery, it doesn’t owe us anything at this point. But we’re not quite ready to see it slip into its long interstellar sleep, and we wish the team good luck while it works through the issue.

Voyager 1 In Trouble As Engineers Scramble To Debug Issue With Flight Data System

December 12, 2023 by 45 Comments

Recently the team at JPL responsible for communication with the Voyager 1 spacecraft noticed an issue with the data it was returning from the Flight Data System (FDS). Although normally the FDS is supposed to communicate with the other subsystems via the telecommunications unit (TMU), this process seems to have broken down, resulting in no payloads from the scientific instruments or engineering sensors being returned any more, just repeating binary patterns. So far the cause of this breakdown is unknown, and JPL engineers are working through potential causes and fixes.

This situation is not unlike a similar situation on Voyager 2 back in 2010 when the returned data showed a data pattern shift. Here resetting the memory of the FDS resolved the garbled data issue and the engineers could breathe a sigh of relief. This time the fix does not appear so straightforward, as a reset of the FDS on Voyager 1 did not resolve the issue with, forcing the team to consider other causes. What massively complicates the debugging is that each transmission to and from the spacecraft takes approximately 22.5 hours each way, making for an agonizing 45 hour wait to receive the outcome of a command.

We wish the JPL engineers involved all the luck in the world and keep our collective appendages crossed for Voyager 1.