This metal miniature is from Warhammer 40K’s first edition (Rogue Trader) and is in the catalogues as “Ship’s Officer”, though he has “Astronaut” on the tab. I think it says GW 88 on the base.
He was sculpted by Trish Carden (Morrison), as per a conversation with her in Jan 2025.
You can see him in White Dwarf #99:
