---
title: "OpenAI Previews GPT-5.6 Series: Sol, Terra, and Luna Models"
source: "Simon Willison 博客（Atom）"
source_tier: "t2"
url: "https://simonwillison.net/2026/Jun/26/openai/#atom-everything"
permalink: "https://feed.astralor.com/items/itm_232e7d7533c5373f1421774f"
published: "2026-06-26T17:10:43.000Z"
score: 56
channel: "ai"
tags: ["Luna","OpenAI","Sol","TERRA","model launch"]
---

# OpenAI Previews GPT-5.6 Series: Sol, Terra, and Luna Models

## At a glance

OpenAI announces a limited preview of the GPT-5.6 series, featuring flagship model Sol, balanced model Terra, and fast affordable model Luna. Terra offers competitive performance to GPT-5.5 at half the cost, while Luna delivers strong capability at the lowest price. As part of ongoing engagement with the U.S. government, OpenAI previewed plans and model capabilities ahead of launch, and at the government's request, is starting with a small group of trusted partners before broader release.

## Key points

- The GPT-5.6 series includes three models: Sol (flagship), Terra (balanced, 2x cheaper than GPT-5.5), and Luna (fast and affordable).
- Terra matches GPT-5.5 performance at half the cost; Luna offers strong capability at the lowest price.
- OpenAI cooperated with the U.S. government, previewing plans and starting with a limited group of trusted partners before wide release.

## Full text

We're beginning a limited preview of the GPT‑5.6 series: Sol, our flagship model; Terra, a balanced model for everyday work; and Luna, a fast and affordable model. Terra has competitive performance to GPT‑5.5 while being 2x cheaper and Luna brings strong capability at our lowest cost. [...] We believe in broad access, and we plan to make GPT‑5.6 Sol, Terra, and Luna generally available in the coming weeks. As part of our ongoing engagement with the U.S. government, we previewed our plans and the models’ capabilities ahead of today’s launch. At their request, we are starting with a limited preview for a small group of trusted partners whose participation has been shared with the government, before releasing more broadly. — OpenAI, Previewing GPT‑5.6 Sol: a next-generation model Tags: gpt, generative-ai, ai-security-research, openai, llms

---

Verify against the original before citing; curated by Astral Feed: https://feed.astralor.com/items/itm_232e7d7533c5373f1421774f