Voyager-1 back on line after software patch works
For the first time since November, Voyager-1 is sending data back to Earth coherently, after engineers figured out a way to isolate a corrupted computer chip.
The team discovered that a single chip responsible for storing a portion of the FDS memory — including some of the FDS computer’s software code — isn’t working. The loss of that code rendered the science and engineering data unusable. Unable to repair the chip, the team decided to place the affected code elsewhere in the FDS memory. But no single location is large enough to hold the section of code in its entirety.
So they devised a plan to divide the affected code into sections and store those sections in different places in the FDS. To make this plan work, they also needed to adjust those code sections to ensure, for example, that they all still function as a whole. Any references to the location of that code in other parts of the FDS memory needed to be updated as well.
The software patch was sent to the spacecraft on April 18, 2024, taking 22.5 hours to get there. It then took 22.5 hours for a response. On April 20th they received a confirmation that the patch had worked. Over the next few weeks more patches will be sent to Voyager-1 to allow it to resume sending science data back to Earth.
Both Voyager-1 and Voyager-2 were launched almost a half century ago, in 1977, and both are now more than more than 15 billion miles from Earth, traveling in interstellar space. Their computers are also the longest continuously running operating systems. Both only have a little more than two years left in their nuclear power supply, which was always expected to run out of power about a half century after launch. That both have continued to function for that entire time is a magnificent testament to the engineers who designed them.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
For the first time since November, Voyager-1 is sending data back to Earth coherently, after engineers figured out a way to isolate a corrupted computer chip.
The team discovered that a single chip responsible for storing a portion of the FDS memory — including some of the FDS computer’s software code — isn’t working. The loss of that code rendered the science and engineering data unusable. Unable to repair the chip, the team decided to place the affected code elsewhere in the FDS memory. But no single location is large enough to hold the section of code in its entirety.
So they devised a plan to divide the affected code into sections and store those sections in different places in the FDS. To make this plan work, they also needed to adjust those code sections to ensure, for example, that they all still function as a whole. Any references to the location of that code in other parts of the FDS memory needed to be updated as well.
The software patch was sent to the spacecraft on April 18, 2024, taking 22.5 hours to get there. It then took 22.5 hours for a response. On April 20th they received a confirmation that the patch had worked. Over the next few weeks more patches will be sent to Voyager-1 to allow it to resume sending science data back to Earth.
Both Voyager-1 and Voyager-2 were launched almost a half century ago, in 1977, and both are now more than more than 15 billion miles from Earth, traveling in interstellar space. Their computers are also the longest continuously running operating systems. Both only have a little more than two years left in their nuclear power supply, which was always expected to run out of power about a half century after launch. That both have continued to function for that entire time is a magnificent testament to the engineers who designed them.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
That is incredible!
Bet they run on Fortran. I well remember the course book “Fortran for Humans”
Of course there were other higher languages back then, but to ensure all software worked, I am betting on the standard Fortran.
Phill O;
Here you go: https://www.allaboutcircuits.com/news/voyager-mission-anniversary-computers-command-data-attitude-control/
Thanks Blair
Wow, the did some stuff in C: that is ground breaking! (for the time)
I think it was Fortran IV I learned.
It’s also a testament to the current-day engineers on the ground who went through what I’m sure was painstaking analysis to determine the source of the fault, and find a way around it. We still have excellent engineers around. Not that I’m taking anything away from the original designers!
Larry: You should take a look at the Voyager flight team that did this work. See the photo from the press release.
I’d say the average age is around 65. These people weren’t there when the Voyagers were built and launched, but they have likely been part of the team for more than a few decades. Almost none are from the last two generations.
The transit time in light-hours (22.5) provides a good personal realization for how far the Voyager(s) have penetrated into “interstellar space”—which is to say, still less than 1 light day out of the 4 light years distance to even the nearest extrasolar star.
So people don’t get the wrong idea, Voyager’s onboard computers are programmed in assembly language, not Fortran. (3 assembly languages for the 3 different types of CPUs.) The Fortran 5 to Fortran 77 to C statement in the All About Circuits article is based on a Wired article which said that about the “control and analysis” software, i.e., the ground-system mission control and analysis software. The original ground system running on Univac mainframe computers was written in Univac Fortran V (“Fortran five”). Circa 1990, the system was moved off the mainframes onto Unix workstations and PCs and parts were reimplemented in C.
You can see some of the FDS computer’s assembly code in the failed memory block in an August 2024 presentation by Bruce Waggoner, “Saving Voyager 1!”. This is a very good, detailed account of the FDS memory problem and the slide with the assembly code appears 23:00 minutes in: https://www.youtube.com/watch?v=dF_9YcehCZo&t=1380s