A thermal blanket is a sheet of silver-colored, thermally reflective material that is used to keep people warm, used to help stabilize people in shock and to hide their heat signatures to avoid detection.
A thermal blanket was used by the SPARTAN-III's and Kurt-051 to cover Dante-G188's body inside the Sentinel manufacturing facility on Onyx to hide him from the Sentinels of Onyx. It was also used on Dr. Halsey when she arrived on Onyx, and later to create a primitive Faraday cage around Halsey when she was working on her laptop, to avoid detection by the Sentinels' electromagnetic sensors. Thermal blankets were also used to hide armed Lotus anti-tank mines from the Covenant.
- Halo: Ghosts of Onyx (First appearance)