The two Voyager spacecraft have been traveling in space for over 46 years.

Their power levels have dropped by about 50%, various instruments have been selectively shut off, yet the spacecraft continue to keep on going and going, sending back valuable science data from interstellar space.

Here are the locations and some vital stats on the two Voyager spacecraft, which were launched on Sept 5, 1977 and Aug 20, 1977 resp.

https://www.nasa.gov/solar-system/nasas-new-horizons-reaches-a-rare-space-milestone/
https://voyager.jpl.nasa.gov/mission/status/

#Voyager
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How big is the software on the Voyager spacecraft? Not very.

The software size was 3K Lines of Code (SLOC) in 1977. Either Fortran or assembly. The memory size is 4K 18-bit words!

So the patch being uploaded is probably even smaller.

The software has been upgraded a few times as mission objectives and operational use cases have changed.

See the graph below for the exponential software size evolution across time and missions.

https://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=D857E325A76033DF71EA0A846635B63B?doi=10.1.1.711.2976&rep=rep1&type=pdf
#Voyager
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Let's take a moment to marvel at the computing hardware on the Voyager spacecraft.

It was built using 1960s technology, with clock speeds measured in KHz and RAM in kbytes, running hand-crafted software, crammed into 4K of 18-bit wide plated-wire memory (similar to but better than core mem). Plus 8-track tape.

The custom-designed hardware and (upgraded) software (and most instruments) are still functioning after 46 years in space!

https://history.nasa.gov/computers/Ch6-2.html
https://hackaday.com/2018/11/29/interstellar-8-track-the-low-tech-data-recorders-of-voyager/
#Voyager
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