It's simple recycling.
Despite Kubrick's attempts to destroy all props and models from 2001 the back of some of the spacesuits ended up in a classic Doctor Who episode and one as part of a wall detail in Blake's 7.
A replica suit for 2010 ended up being used in Babylon 5 and when that was lost had to be rebuilt from scratch.
Bits of the Nostromo set ended up on classic Doctor Who as well.