OpenAI on Friday released three versions of GPT-5.6, called Sol, Terra, and Luna, as a limited preview to a small number of companies as part of an ongoing engagement with the U.S. government. While Sol is the latest flagship model and the most powerful, Terra strikes a balance between efficiency and power, and Luna is fine-tuned for speed and affordability. "GPT‑5.6 Sol launches with our most Source: The Hacker News