ΔE 9.8, close: similar, with a visible difference side by side. Hydromiel Yellow is more saturated, cooler than Space Dust. They are different kinds of paint: Army Painter Space Dust is an opaque base/layer paint and Green Stuff World Hydromiel Yellow is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Hydromiel Yellow is more saturated, cooler than Space Dust. They are different kinds of paint.
The same difference applies the other way round: Space Dust is more muted, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Space Dust on the colour wheel See Hydromiel Yellow on the colour wheel
All matches: Space Dust equivalents · Hydromiel Yellow equivalents