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posted by martyb on Saturday December 16, @03:31AM   Printer-friendly
from the one-heck-of-a-service-call dept.

NASA's veteran Voyager 1 spacecraft has stopped transmitting engineering and science data back to Earth.

The issue appears to be with the Flight Data System (FDS), which is not communicating correctly with one of the probe's subsystems - the Telemetry Modulation Unit (TMU).

Rather than useful data, the TMU is simply transmitting a repeating pattern of ones and zeroes as if it were "stuck," according to NASA.

The FDS is responsible for collecting data from Voyager 1's science instruments as well as on the general health of the spacecraft. This is all packaged up and sent back to Earth by the TMU. Having worked through the possibilities, the Voyager team reckons the issue lies with the FDS.

"This past weekend the team tried to restart the FDS and return it to the state it was in before the issue began, but the spacecraft still isn't returning useable [sic] data," NASA says.

Engineers face multiple challenges. First, the Voyagers are famously old – dealing with their quirks involves poring through decades-old documents. Commands sent to the probes must be meticulously verified to prevent unintended consequences.

And then there is the sheer amount of time it takes to communicate with the Voyagers. A command from mission control on Earth will take more than 22 hours to reach Voyager 1. It can, therefore, take 45 hours to determine whether a given instruction worked as expected.

NASA reckons it will be several weeks of work for engineers to devise a new plan to deal with the problem.

Voyager 1 suffered a telemetry glitch in 2022 that resulted in garbled data on the probe's attitude being sent back to Earth. That issue was resolved by switching to a different computer. However, in that instance, Voyager 1 continued returning science data. The latest problem has stopped that.

The next time you find yourself having to diagnose and fix a problem remotely, remember that it could always be worse, even if sometimes it feels as though that misbehaving server is also 15 billion(*) miles away.

Given the limit imposed by the speed of light, a signal sent to Voyager 1 and immediately returned takes more than 16.6 hours. That's more than 2/3 of a *day*!

Original Submission

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Humanity's Most Distant Space Probe Jeopardized by Computer Glitch 14 comments

Voyager 1 is still alive out there, barreling into the cosmos more than 15 billion miles away. However, a computer problem has kept the mission's loyal support team in Southern California from knowing much more about the status of one of NASA's longest-lived spacecraft.

The computer glitch cropped up on November 14, and it affected Voyager 1's ability to send back telemetry data, such as measurements from the spacecraft's science instruments or basic engineering information about how the probe was doing. [...] "It would be the biggest miracle if we get it back. We certainly haven't given up," said Suzanne Dodd, Voyager project manager at NASA's Jet Propulsion Laboratory, in an interview with Ars. "There are other things we can try. But this is, by far, the most serious since I've been project manager."

Dodd became the project manager for NASA's Voyager mission in 2010, overseeing a small cadre of engineers responsible for humanity's exploration into interstellar space. Voyager 1 is the most distant spacecraft ever, speeding away from the Sun at 38,000 mph (17 kilometers per second). [...] The latest problem with Voyager 1 lies in the probe's Flight Data Subsystem (FDS), one of three computers on the spacecraft working alongside a command-and-control central computer and another device overseeing attitude control and pointing. [...] In November, the data packages transmitted by Voyager 1 manifested a repeating pattern of ones and zeros as if it were stuck, according to NASA. Dodd said engineers at JPL have spent the better part of three months trying to diagnose the cause of the problem. She said the engineering team is "99.9 percent sure" the problem originated in the FDS, which appears to be having trouble "frame syncing" data. [...] "It's likely somewhere in the FDS memory," Dodd said. "A bit got flipped or corrupted. But without the telemetry, we can't see where that FDS memory corruption is."

[...] "We have sheets and sheets of schematics that are paper, that are all yellowed on the corners, and all signed in 1974," Dodd said. "They're pinned up on the walls and people are looking at them. That's a whole story in itself, just how to get to the information you need to be able to talk about the commanding decisions or what the problem might be." [...] "It is difficult to command Voyager," Dodd said. "We don't have any type of simulator for this. We don't have any hardware simulator. We don't have any software simulator... There's no simulator with the FDS, no hardware where we can try it on the ground first before we send it. So that makes people more cautious, and it's a balance between getting commanding right and taking risks."

[...] The spacecraft's vast distance and position in the southern sky require NASA to use the largest 230-foot (70-meter) antenna at a Deep Space Network tracking site in Australia, one of the network's most in-demand antennas.

"The data rates are very low, and this anomaly causes us not to have any telemetry," Dodd said. "We're kind of shooting in the blind a little bit because we don't know what the status of the spacecraft is completely."

Previously on SoylentNews:
Engineers Work to Fix Voyager 1 Computer - 20231215

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  • (Score: 1) by ssvt on Saturday December 16, @11:20AM

    by ssvt (14071) on Saturday December 16, @11:20AM (#1336660)


  • (Score: 3, Interesting) by VLM on Saturday December 16, @03:01PM

    by VLM (445) on Saturday December 16, @03:01PM (#1336678)

    I wonder what the pattern is.

    The crypto-bros are good at spotting stuff in apparent randomness so releasing the data couldn't hurt anything and might help.

    I'm sure they already checked the "obvious" stuff like a shift register not resetting after the correct number of bits.

    I find the idea of trying to diagnose something using nothing but a bitstream to be interesting.

    Of course if its boring alternating 1/0 that's not likely to be helpful.

  • (Score: 2) by jb on Sunday December 17, @06:43AM

    by jb (338) on Sunday December 17, @06:43AM (#1336750)

    Surely this is the beginning of how it becomes V'ger...