Earlier in the month, I was thinking about "outer space" in the context of my Dwimmermount campaign and OD&D's treatment of the planes. Since then, I've given it some more thought and have decided that I'd be conflating the Astral Plane and interplanetary space. This is pretty easy to do, since there aren't many Astral-related effects in OD&D until very high levels. Since I'm sticking to the LBB's spell levels, this is even easier. Now, outer space -- which I'll probably call "astral space" or something similar -- will, unlike the traditional Astral Plane, be a place characters can enter physically rather than spiritually. There are no silver cords or bodies left behind on earth or anything of that sort. Instead, it'll be a vast void between the worlds, inhabited by numerous creatures malevolent and benign and requiring the use of certain protective spells and/or items to survive if one is not native to this environment. Interestingly, I like the idea of the Ethereal Plane as presented in OD&D, but, alas, the name has to go, since astral space, as I'm now conceiving it, is suffused with ether. That necessitates a new name for the Ethereal Plane, but that's a small point.
Astral space is getting any consideration at all, because the campaign -- and I'm now two session recaps behind, I know -- is getting to the point where the days when the Thulians rose up in rebellion against the Red Elves of Areon will prove important. From the beginning of the campaign, I wanted to make it possible for the PCs to travel to the Red Planet and interact with its inhabitants. As I've noted numerous times, I'm a big fan of Burroughs and Areon is definitely an homage/pastiche of the Barsoom, albeit a somewhat more sinister/Lovecraftian one. The Eld once traveled across astral space, seeking out new sources of azoth, after having spent millennia depleting Areon's own supply of it. This magical catastrophe has brought the planet low, reducing it to a dust-blown desert where Chaos now has free rein and Eldritch dominions war with one another -- and their former slaves -- for the last remaining sources of azoth, which guarantees not only their survival on a dying world but also promises the chance of reclaiming their lost empire.
I'm not in any hurry to get the PCs to the Red Planet -- or the Green Planet of Kythirea, for that matter -- but I would like to see them get there some day. There are several portals within Dwimmermount that lead to Areon and there are a couple of sections within the megadungeon where Eldritch influences are still apparent. I know I'll enjoy injecting dashes of Burroughs and Kline into the campaign. It's something I've wanted to do since I started poring over the LBBs and saw all those references to banths, tharks, and white apes. With luck, 2010 will be the year when I finally get to do it.