With Major Matt being so popular I often see custom toys for Mattel's Man in Space online. There's some on Ebay right now. So I had to look twice when I saw this as I thought it too was a Major Matt custom job.
It isn't. Its a Moon Rover by CBS Toys from 1984. This is a toy and a company I don't know. Were there more in the line or was this a one off? Would it even work as a Matt Mason vehicle - is it the right scale?