Knowledge of Zheng He’s voyages were suppressed by emperors following his sponsor (the Yongle Emperor) while the moon landings are celebrated by contemporary media (moonwalker Neil Armstrong died recently; this post a synthesis of comments on two posts about Armstrong) but this has everything to do with the vast differences in host contexts and little to nothing with the rationale and impact of the respective explorations.
To all who overly credit the space race for the environmental movement or mid-late 20th century technical advances, you egregiously underestimate how and why people care about and for the environment and contribute to progress. To all inspired by totems, for shame. Totems are a barrier to calm thinking and acting for more good and against bad.
(None of this is to deny the astounding performances of Armstrong, Zheng, or other great explorers; their tenacity, intelligence, practicality, and such are qualities that nearly all humans could use more of. Zheng probably and certainly many great European explorers not long after were also mass murderers, and many astronauts and cosmonauts participated in the military of their respective murderous imperial regimes, but that’s another topic.)