I thought I remembered some references to Voss in the GSF materials, but I could be remembering it wrong. Or it might have been intended as an easter egg and not a continuity connection.
Anyhow, has there been an official word on if GSF is or is not connected to the Sentinels multiverse?
Yes they are set in the same universe, but hundreds of years apart.
According to Christopher, all of his stories that we know of so far inhabit the same Multiverse. The metahumans from GSF, for example, are the distant descendants of the humans in SotM.
vaguely and thousands upon thousands of years apart.
There's a Parsons on one of those ships though. Just remember that when you play.
For reference:
Promo for GSF: Vognild Prime - Homeworld of the Maerynians, which Voss conquered, "but that was millenia ago."
http://sentinelsofthemultiverse.com/multiverse/heroes/tempest
Tempest - He is a Maerynian and refugee from Vognild Prime after Voss conquered it.