What distro does NASA use?

I'm curious to know, what operating system distribution, or distro, does NASA utilize for their technology and computing needs? It's fascinating to think about the high-level requirements and specifications they must adhere to in selecting a suitable platform for their mission-critical tasks. As a cryptocurrency and finance professional, I'm also intrigued by the parallels between the rigorous security measures employed by NASA and those necessary for safeguarding digital assets and transactions in the blockchain space. So, what distro does NASA ultimately rely on to support their groundbreaking work?