NASA specialists have sent a software update to the Voyager 2 spacecraft to avoid the failure that Voyager 1 faced in 2022, writes The Register.

Last year, Voyager 1’s onboard computer suddenly started sending distorted reports to Earth. Engineers found out that the problem then concerned the Articulation and Attitude Control System (AACS). This is a tool that controls the orientation of the spacecraft, including keeping their antennas pointed toward the Earth to transmit data.

NASA explained that AACS was writing commands to memory rather than executing them. One of the missed commands led to a distortion of the AACS status report before it even reached the engineers on Earth.

“The team determined the AACS had entered into an incorrect mode; however, they couldn’t determine the cause and thus aren’t sure if the issue could arise again. The software patch should prevent that,” NASA reported.

The patch was sent on October 20, and the corresponding tests are scheduled for October 28. However, due to the spacecraft’s venerable age, the consequences of patching can be unpredictable. Therefore, it was decided to conduct such measures for Voyager 2 first.

The fact is that this spacecraft is closer to the Earth than Voyager 1, so communication with it will be a little faster, and downloading and testing will be easier. In addition, Voyager 2’s data is considered less valuable, so its hypothetical failure, although undesirable, would be more acceptable.

The computers of the Voyager spacecraft, created in the early 1970s, have only 68KB of memory and processors with a clock speed of only 250 KHz. The performance of the systems is no more than 8000 commands per second. At the same time, the data transfer rate has dropped to 160 bps, bits, not kilobits per second. That’s why it took 18 hours to transfer the new patch.

NASA is also implementing other measures aimed at further operation of both spacecraft. We are talking about problems with the engines that keep the antennas of both Voyagers pointed at the Earth. Now they are not in the best condition. Therefore, they will try to remove the accumulated fuel residues from the tubes connected to them. To do this, the specialists decided, in particular, to reduce the frequency of engine starts, during which such clogging occurs.