Growth is critical for a tech startup's long-term success, as it determines whether it will stick around or fizzle out into obscurity. More than 70% of startups fail because of growth issues (e.g., premature scaling). The existing research and knowledge on the capabilities and mindset required to sustain startup growth momentum are limited. This study adopts a multiple case study method from a meso-level perspective to uncover how successful tech startups in Egypt managed to sustain their growth during varying levels of environmental turbulence (i.e., waves and storms). Our findings indicate that startup momentum is based on the equilibrium of the evolution of these three constellations: Stability (i.e., Laying the Foundation and Strategic Direction), Agility (i.e., Dynamic Capabilities and Improvisational Capabilities), and Team & Leadership. These constellations are interconnected and possible by adopting a Service-Dominant Logic, which involves co-creating value throughout the ecosystem. We also offer a new perspective on how growth hacking strategies can achieve sustainable growth by creatively leveraging startup resources and the entrepreneurial ecosystem's support. We propose a conceptual model, "The Constellations to Sustain Startup Growth Momentum," to set the stage for future researchers to further inquire into the capabilities required for startups to sustain their momentum and understand the influence of different entrepreneurial ecosystem factors on startups. We also suggest ten pointers to help entrepreneurs identify and surpass startup blindspots to ensure growth.