>The easiest part about Starship is the booster because its not doing anything F9 isn't already. Just at a much larger scale. That of course isn't easy either.

>The easiest part about Starship is the booster because its not doing anything F9 isn't already. Just at a much larger scale. That of course isn't easy either. Scaling up in this context isn't simple at all. For all the recognition of the complexity of rocket science, structural engineering is perhaps the most underappreciated. Scaling up in multiple dimensions often means different things need to be scaled at different rates. Hydraulic and atmospheric modeling is similar in this respect. You pick the variable(s) that you want to scale linearly, and then have to resolve all the other variables in terms of what you've fixed. Lots of dimensional analysis, and then experiments to calibrate the results to be meaningful. For instance, max ultimate moment loading is generally the controlling factor for determining beam strength, which in turn determines the required beam cross section and weight/span. However, as beam span length increases linearly, moment increases exponentially for the same load. And scaling up likely increases the external loading, such that moment increases to the 4th power as base dimensions increase linearly. And then needing a bigger/stronger beam cross-section increases the self-weight that also needs to be supported. Things can quickly runaway in certain configurations, when you start to account for volumetric increases in fuel capacity, and dynamic loadings like impact forces on fuel tank baffles, which themselves are often scaled to the 3rd or 4th power of the fuel weight, and 2nd or 3rd power wrt to the relative change in velocity. And finally there's the structural harmonics and vibration, which all increase in force faster than linear increases in span, and affect structural serviceability (lifetime loading cycles).