Meg Bowles - her 2011 release, A Quiet Light, is one of the best fusions of space and ambient in years. To release something this excellent after a more than 10 year absence is, IMO, unprecedented.
Great call. Back in the day, it seemed she was always in the shadows of the space music giants (Demby, Stearns, Serrie, etc.), but she's really done something awesome and unique with this release, expertly traversing a very fine line between classic space music and pure ambient.
I've been enthralled by Seren Ffordd's music ever since hearing The Portal's Dreaming on my girlfriend's home theater system (ok, technically, it was her dad's) while playing Dead Space. I'd just splurged on a ton of umbra/penumbra releases and loaded them all up into the CD changer. The Portal's Dreaming came up right when I entered a particularly eerie zero-g section of the game. It all fit together just perfectly. I definitely hope The Martian Chronicles gets Andy some more exposure.
Tau Ceti also merits mention here. He's mostly known as Gigi's collaborator on Celestial Geometries, but he has some great solo releases as well. Some of his EPs are delightfully otherworldly and experimental (Achernar, Albhali, Pulsar, etc.). Achernar, in particular, is quite the trip.