These are our rules for battle games, featuring the wonders of steam technology and the awesome might of otherworldly marvels, are based on the renowned Brother Against Brother system (originally designed by Ivor Janci) from H.G. Walls.
The Sword and The Flame (TSATF to veterans) is a wonderfully versatile set of rules by Larry V. Brom. It bills itself as "a set of introductory rules for the conduct of miniature battles of the British Empire" and is focused primarily on the 1870-80s. TSATF is well proven on its home ground, and is a game for those more interested in story and "stirring actions" than competitive gaming (and thus approved by the Station Management.) Check out TSATF for yourself at its web page.
The official description of TSATF speaks of the "British Empire." Obviously we have had to broaden the scope a bit (given our principal locale is on Mars) as well as add some technical wonders (given our bent for VSF.)
We have reconstituted our early adaptations of Martian battles using TSATF. You can download them here.
On the rules front, there is also G.A.S.L.I.G.H.T. (Glorious Adventures in Science Loosely Involving Generally Historical Times) by Christopher Palmer and John R. "Buck" Surdu. These are a set of mechanics for playing out even more "cinematic" skirmishes than TSATF and are already tailored to deal with VSF. Rousing!
We don't have a specific adaption of our Mars to these rules, but the rules are "generic" and you can easily tailor them to suit your own vision.
Learn of some of the sources involed in populating Station Management's gaming tables HERE