There are some recurring themes in Kim Stanley Robinson’s fiction: ecology, anticapitalist politics, mountain-climbing, and in particular time – the ephemerality of the present, the irrecoverability of the past, the contingency (or otherwise) of the future, the unreliability of memory.
But there are also some very specific recurring images that seem to have captured the author’s imagination (and certainly capture the reader’s); and one of these is the mobile city of Terminator on Mercury, forever moving across the night side of the planet, a few minutes ahead of the terrible sunrise.
It shows up in two of his earliest works, the novel The Memory of Whiteness and short story “Mercurial” (both from 1985); then in the later novel Blue Mars (1996); and most recently in 2312 (2012) – even though these stories all take place in (sorta) different timelines. But each description has its own style and contributes something different to the story it’s in.
The most recent description is happily online: enjoy.