What set is this piece used for i have a Lego from the 80s. I can see there are space pieces in grey and blue. I am wondering if this piece is for a space set and if so which one. Any help much appreciated!!
These are Panel 4 x 4 x 6 Corner Convex Ribbed 

They were mainly use as decorative pieces on corners in classic space sets.

In light grey they came only in one Set: Solar Power Transporter 


(photo from Bricklink)