Right, I was talking about a sci-fi failure mode where the onboard program goes haywire and it ends up actively station keeping and maintaining the block for hu

Right, I was talking about a sci-fi failure mode where the onboard program goes haywire and it ends up actively station keeping and maintaining the block for hundreds of years. Is 1.7% not something to worry about? IIRC, Solar variance of 0.1% has correlated with a 0.32F temperature variance. If that relation were linear, that would amount to almost a 5.5F variance. I'm not proposing this as a 'hard scifi' model for a story, but you could tweak the scenario to get suitably scary failures (multiple shades)