Throughout 5 months of troubleshooting, Voyager’s floor crew continued to obtain alerts indicating the spacecraft was nonetheless alive. However till Saturday, they lacked perception into particular particulars about Voyager 1’s standing.
“It is just about the identical as it’s,” Spilker stated. “We’re nonetheless within the early levels of analyzing all of the channels and taking a look at developments. Temperatures have dropped somewhat bit over this era, however we’re seeing just about every part we anticipated. And That is all the time excellent news.”
Rearranging the code
By investigation, Voyager’s floor crew found that one chip liable for storing a part of the FDS reminiscence had stopped working, maybe attributable to a cosmic ray strike or growing old {hardware} failure. This affected a few of the laptop’s software program code.
“It took away a few of the reminiscence,” Spilker stated. “All they need to do is relocate that code to a distinct a part of reminiscence, and something that makes use of these codes or subroutines can entry the brand new location in reminiscence and run it. .”
The unhealthy chip solely corrupted about 3% of the FDS reminiscence, so engineers needed to port the code to a different a part of the reminiscence financial institution. However in keeping with NASA, no single location is massive sufficient to carry a whole part of code.
So the Voyager crew break up the code into sections and saved them in numerous places in FDS. This wasn’t only a copy and paste job. Engineers needed to change some elements of the code to ensure every part labored collectively. “References to that code’s location in different elements of FDS reminiscence should even be up to date,” NASA stated in an announcement.
NASA’s new mission has a {hardware} and software program simulator on the bottom the place engineers can check new procedures to make sure they do no hurt when uplinking instructions to the precise spacecraft. Due to its age, Voyager doesn’t have a floor simulator, and far of the mission’s authentic design documentation stays in paper kind and has not been digitized.
“It was actually simply my eyes that noticed the code,” Spilker stated. “So we needed to triple-check it. Everybody was wanting over it and ensuring all of the hyperlinks had been linked.”
This was simply step one in restoring Voyager 1 to full performance. “He was fairly assured it was going to work, however he wasn’t one hundred pc positive till it really occurred,” Spilker stated.
“The rationale I did not do every part in a single step was as a result of the quantity of reminiscence I may discover straight away was very restricted. So I prioritized one information mode (engineering information mode) and restored that mode. ,” stated Jeff Mellstrom, a JPL engineer who heads Voyager 1’s “tiger crew” tasked with overcoming the issue.
“The subsequent step is to rearrange the remaining three scientific information modes which can be actively used, however they’re primarily the identical,” Maelström stated in a written response to Ars. “The primary distinction is that we at the moment are extra constrained by the out there reminiscence. We now have concepts the place we will rearrange the code, however we’re not but capable of absolutely consider or resolve on the choices. is step one beginning this week.”
