Very interesting OS that is FOSS now. By v3 it ran on multiple CPU architectures. With some of the manycore CPUs appearing in recent years, this is crying out for a revival.
The name of the complete system is called Ares, and Helios is a small component of that. Essentially, to most people, it's an implementation detail/internal codename that will not really see much use for marketing efforts.
It does not look like the other Helios project is going anywhere, so I'm not too concerned with the naming conflict right now.
The other "Helios" project was a commercial operating system from Perihelion Software, which was subsequently kinda open sourced after the company went bust (which is the GitHub repo posted).
There are a couple of books about it from Prentice-Hall: ISBN 0-13-381237-5 and ISBN 0-13-386004-3, plus various academic papers, commercial software for the OS (mostly development tools), open source software (X11, gcc, other stuff), etc, etc.
It too was a micro-kernel, with a very Plan9-like global name system implemented by applications plugging into the name server protocol.
If nothing else, it might be of interest to read up on it, but given the similarities between the projects, it seems to be an unfortunate naming collision.
https://www.theregister.com/2021/12/06/heliosng/
Very interesting OS that is FOSS now. By v3 it ran on multiple CPU architectures. With some of the manycore CPUs appearing in recent years, this is crying out for a revival.