The narrative structure of your story effectively captures the tension and intrigue of a space exploration adventure. I think the establishment of the setting around Alpha Centauri is particularly good. The dialogue is also a strong point; it feels natural and helps to develop the characters quickly and efficiently, giving each a distinct voice and personality.

While the story is engaging and the suspense builds well, I think there's an opportunity to deepen the impact through more detailed descriptions of the characters' reactions to their environment. Additionally, I feel like the scientific reasoning behind the lack of microorganisms could be expanded a bit. Clarifying the sequence of events leading to the climax could also enhance the reader's understanding and engagement, ensuring that the final twist is both surprising and plausible.

This is a compelling piece that blends scientific exploration with the elements of a thriller. The story is well-placed, maintaining reader interest throughout. The story’s climax is particularly striking. However, I think refining the scientific explanations and enhancing the environmental descriptions could make the narrative even more compelling and believable.Keep up the great work!