But, are those polar orbits more accessible from Shetland than from more equatorial locations? Is that potentially useful? Does the lack of earth assist matter for the kinds of small satellites that can be thrown by the rockets applying to use this site? (I don't know the answers, it's not a rhetorical question.)

And where else can Europe launch from (under its own control) other than French Guiana? Shetland is closer than that, if a bit shorter on cool lizards and post-launch umbrella drinks. Maybe the idea is to keep using French Guiana for full-scale Ariane launches, and Shetland for cheap launches of little things that would be too expensive to ship across the Atlantic?

> It will then travel north west, out over the Norwegian Sea and the North Pole, before hopefully entering orbit around 500km above the surface of the earth.

Looks like that's what theyre going for. There's already a lot of equatorial launch sites, I'm not sure how many polar ones there are