Any substance can have unwanted affects to the surfaces is lands on. It isn’t only lenses or windows or even mirrors that are optical. The solar arrays depend upon sunlight not being reflected away or absorbed by any molecules landing on them. The same goes for thermal radiators, where the radiative properties are those of the surface material, and water or other molecules can change the amount of thermal radiance they get; these, too are optical surfaces. Thermal blankets have the same problem, as they are designed to maintain a certain temperature on their insides, and if they radiate their outer surface differently, being optical surfaces, the inside surface maintains a different (though perhaps only slightly different) temperature. In fact, you can think of every exposed surface as an optical surface that affects the overall thermal properties of the space station, even if only slightly.

It is similar to Frank Solomon’s question about the forces, thus the torques, applied by the leak to the space station. Small as these effects are, they are definitely present.

This is one of the reasons that spacecraft are made in the controlled environments of cleanrooms. Along with dust, fingerprints, and other material contaminations, we try to limit these kinds of volatile materials from condensing on the inside and outside surfaces. The thermal engineer designed his system carefully, and we don’t want to upset that in a way that causes problems with the operation of the spacecraft.

When something like this happens, a lot of controllers are watching to see how their own systems are affected.

I too wonder what Isooctan is and Fisher Scientific has it listed as: Isooctane, or 2,2,4-trimethylpentane, is a toxic, flammable, volatile, organic alkane, and an isomer of octane. Available in various quantities and reagent grades, it is an anti-knocking agent in gasoline. Other applications include use as a non-polar solvent.

Frank Solomon,
This small new force is there, and it does need to be balanced, and the total torque is larger if the source of the force is farther from the center of mass than if it is closer. ISS has some reaction wheels that handle attitude control. There are a number of forces and torques that act on the station, and the usual attitude is to fly with one side constantly facing Earth, so ISS is constantly rotating relative to the inertial reference frame. These reaction wheels are always kept busy, so the effects on the attitude control system are low on the list of concerns of the controllers. ISS has automatic control systems that can handle it.

Considering that it took a while for the hole in that one Soyuz to open up, a few years back, I think this is a correct analysis. We can only hope that the Russian quality control has improved over the years, because we don’t have a lot of direct evidence that it has.