- Dr. Mara Oseivoice: en-US-AriaNeural
- Xenolinguist, 38, Ghanaian-British. Quiet intensity. Speaks precisely. Has a habit of going silent for long periods when thinking — colleagues find it unnerving. Lost her sister to a deep-space accident eight years ago; doesn't talk about it. Loves the idea of contact more than she loves people. Discovering the signal changes that order.
- Commander Idris Vancevoice: en-US-GuyNeural
- Station commander, 52, Nigerian-American. Former IESA logistics officer who worked his way up through eighteen years of deep-space postings. Methodical, careful, protocol-bound — not because he lacks imagination but because he has seen what happens when protocol breaks down. Respects Mara enormously. Disagrees with her almost always.
- Dmitri Sobelvoice: en-US-EricNeural
- Engineer/pattern analyst, 31, Russian. Brilliant in the way that makes other brilliant people feel ordinary. Uses humor as armor.
- Dr. Petra Sandvikvoice: en-US-JennyNeural
- Station psychologist, 45, Swedish. Calm, methodical, asks the right questions. Reveals herself as something more complicated mid-story. Not a villain — a true believer in a different kind of truth, one that has made her choices no less difficult to make.
- Yemi Adaoravoice: en-US-MichelleNeural
- Medic with a background in computational linguistics, 29, Nigerian. Smart, empathetic, tired of being underestimated. Becomes an essential part of the translation team. Has a wry humor that surfaces only when things are at their worst.
- OKONKWO_REYESvoice: en-US-AnaNeural
- Station senior systems officer, broad and steady, speaks rarely but directly
- NARRATORvoice: en-US-ChristopherNeural
- Third-person narrator
- AMARA_CHENvoice: en-US-JaneNeural
- IESA official communicating from Earth, weary and diplomatic
- FREIGHTER_REYESvoice: en-US-TonyNeural
- Helix Dynamics paramilitary contractor commander, professional and calculating
- YUSUF_ADEYEMIvoice: en-US-DavisNeural
- Comms monitor stationed two decks away, breathless and reactive