Recs.
Updated
Star Frontiers was a boxed game by TSR, Inc. 1982. The first rules set was later called "Alpha Dawn". It is a SF setting with 4 alien species (Dralasite, Human, Vrusk, Yazirian). The combat system is fast-moving and percentile-based with a limited set of 13 Skills, each broken into many Subskills of the form Base%+10%/Level of Skill. Very satisfying combat in 6-second rounds handling personal, vehicle and aerial combat at the same time. A second box added starship design and combat rules, and the Zebulon's Guide supplement gave more setting background and an expanded skill system with a color Action Table to obtain degrees of success.
Today a free fan edition of most of the Star Frontiers material can be downloaded online.
SpecsUpdate
Pros
Pro Fast percentile combat-system able to combine personal, vehicle and aerial combat together
Percentile combat-system is based on a Base Skill % + 10%/Level of Skill. Skill levels are from 1-6. Combat occurs in six-second turns. Modifiers for melee, ranged, vehicle and aerial combat are added to the base %'s. Rolls of 01-05 are automatic successes, 01-02 in addition are "Knockouts". But rolls of 96-00 are Failures no matter how good you may become.