Many orbital launch vehicles use a combination of a chilled oxidiser (usually LOX when dealing with liquid-fuelled rockets) and a fuel (commonly RP-1, but with many designs now opting for Methane). Both LOX & Methane require super-cooled temperatures to maintain liquidity: the boiling point for LOX is −182.96°C, while Methane's is -161.5°C.
SpaceX has attempted to take this lower (with varying success...) by super-chilling their LOX and RP-1 (to the point where the latter starts acting most similarly to a watery gel) down to -206.67°C & -6.67°C respectively.
Falcon 9 however, is painted in a proprietary blend of white on top of its Aluminum-Lithium alloy. The understanding, at least within casual spaceflight fan circles, is that this reflective coating is enough to prevent excessive heat buildup and eliminate or reduce propellant boiloff.
The CRS-13 mission looks set to change this slightly — with the Falcon 9 first stage continuing to sport its soot from its previous flight:
Does this added layer of darker material influence the thermal properties of the vehicle with respect to its propellant?
Furthermore, RocketLab's Electron launch vehicle completely bucks the trend of white rocket designs; instead opting to stick with the sleek & shiny black of its Carbon-composite fibre body:
Propellant thermal management should surely be in full play with this vehicle, especially considering it has a much higher surface to volume ratio, when compared to Falcon 9.
So, just how much does the exterior color of the vehicle affect thermal management protocols, the propellant, and rates of boiloff? Is this a genuine concern or something that has endlessly made the rounds of spaceflight-geek circles with no substantial evidence?
Ideally, I'm looking for an answer which has citations to prior work, or studies conducted recently on modern launch vehicles.