# Why is the Nancy Grace Roman Space Telescope (WFIRST) coronagraph considered “beyond-state-of-the-art”?

After about 01:30 in the NASA video NASA's Nancy Grace Roman Space Telescope: Broadening Our Cosmic Horizons the narrator says:

To deepen its study of exoplanets the Roman Space Telescope will house a beyond-state-of-the-art chronograph, that will directly image and analyze Neptune-size planets in orbits slightly larger than Earth’s.

The video shows a diagonal mirror with an articulated phase shifting surface followed by some kind of what I am guessing is a pupil filter.

Questions:

1. What is this particular coronagraph or its design called, and where can I read in detail about how it works? Please feel free to add a short summary in the answer if so inclined.
2. What is it about the design that would be considered "beyond-state-of-the-art"?

• I'm sure Q2 is just journalistic nonsense. If it is beyond state-of-the-art, then it can't be built. It probably just means state-of-the-art. – ProfRob May 21 '20 at 9:26
• @RobJeffries I'd assumed so; answers to What is it about the design that would be considered "merely-state-of-the-art"? would be welcomed as well. – uhoh May 21 '20 at 9:33