In the 40+ years since their launching, after traveling through the solar system and now beyond, what would the Voyager probes look like today if we could see them up close? Would they look noticeably different, namely due to any damage from space travel (dust/debris/rays/etc)?
1$\begingroup$ The golden Record is made out of gold because it hardly chemically interacts with anything. The decission to make it out of gold was made for it to endure a billion years been readable (so cosmic rays will also do little damage). Besides that my guess is that the parabolic antenna will suffer the largest change since it is white and cosmic rays tend to darken exposed surfaces. If Voyager experiences any collision with micrometeoroids after millions of years it will probably start to rotate uncontrolably. You would see a tumbling probe with a dark dish and a still quite shinny gold disk $\endgroup$– SwikeNov 7, 2019 at 11:39
2$\begingroup$ @Swike the golden Record was not made out of gold, it is gold plated only. $\endgroup$– UweNov 7, 2019 at 12:42
$\begingroup$ I am sad and frustrated that the answer is not "nuclear-reactor-powered monster with ion drives and laser comms" $\endgroup$– ikraseNov 11, 2019 at 2:54
The probes' various materials -- metals, polymers, thermal shielding, glass, composites -- age in various ways.
A quick summary would be hard: that question mentions the 560+ page NASA Conference Publication 3257 LDEF Materials Results for Spacecraft Applications (compiled by Drs. Ann F. Whitaker and John Gregory, October 27-28, 1992) on 6 years' exposure for 57 test specimens in Earth orbit. The Voyagers suffer less solar radiation than these specimens did, but the report addresses many other aspects of space weathering.