India, July 23 -- Nine full-scale test flights in, SpaceX is still battling the daunting challenge of making its Starship rocket function as planned. This 120-metre-tall launch vehicle, the largest and most powerful ever built, is central to Elon Musk's bold vision for both Mars missions and mass satellite deployment. Yet, after more than two years of development, the company faces mounting questions about whether Starship will ever deliver on its promises.

SpaceX's aggressive, test-and-learn approach is no secret. Half a dozen explosive incidents have marked Starship's journey so far. Just this year, there have been launches scattering debris over wide areas, including reports of fragments falling near the Turks and Caicos Islands. Even...