Given that they can, they now need to build a larger one, which with more surface area will be more difficult than this one.

In terms of 'risk stacking'[1] they are definitely a big step closer to being in successful.

[1] Risk Stacking is the set of risks a company faces between the current time and being operational. Technology risk is always level 1 (can they build what they say they can build), after that comes market risk (will people buy it with enough margin for both continued operation of the company as well as further development), and the third is execution risk (can they operate efficiently enough to create a net positive economic product.)