Since the first days of the International Space Station on orbit, there have been photo surveys. There are only so many windows for the astronauts to check the outside, and it helps to see how the station is holding up. These were done by rendezvousing Soyuz capsules and Space Shuttles, and it is expected that the commercial cargo vehicles will do the same.
In September 2008, a Soyuz photo survey saw damage to the starboard S1 thermal radiator, and was it a doozie.
See the white folded panel array to the right of the pressurized modules? You can’t miss the big tear in the aluminum, where it has peeled away from the honeycomb core.
In there somewhere is an ammonia circulation system, which moves any excess heat from the American section of ISS out to these radiators. The radiator coating is a ceramic with low solar absorptance and high infrared emittance, meaning that it reflects most of the sun’s energy rather than absorbing it and easily radiates heat out into space. I could bore you to tears with data on this coating, because the performance of the coating was critical for the whole radiator. Instead, I’ll just give you a bit of trivia. The original binder for this coating was the same used by Motorola in their black and white TVs, and when they quit making black and white TVs and thus the binder, we had to run a bunch of tests to find an adequate replacement.
I am trying to figure out just how big the tear is. Nasaspaceflight.com said 30 cm x 80 cm, but I think it has to be bigger than that. Here’s a nice photo of the radiator during deployment testing for an idea of scale.
There was some discussion of replacing the entire radiator while the Space Shuttle was still flying, but it was decided to shut off the ammonia to that loop and keep flying like it is. Our astronauts are comfortable, and that’s what matters.