Answer: USA
Notes: The National Aeronautics and Space Administration (NASA) of the USA and the U.S. Military have collaborated for a project named Demonstration Rocket for Agile Cislunar Operations (DRACO). The project aims to launch a nuclear-powered satellite to Earth's orbit in late 2025 or early 2026. The spacecraft for the project is developed by Lockheed Martin. The project involves an in-space test of Nuclear Thermal Propulsion (NPT) technology, marking a significant technical advancement.
