The Air Force had also started their Lunex Project in 1958, also with a goal of building a crewed lunar outpost. Like NASA, Lunex favored the direct ascent mode, and therefore required much larger boosters. As part of the project, they designed an entirely new rocket series known as the Space Launcher System, or SLS (not to be confused with the Space Launch System part of the Artemis program), which combined a number of solid-fuel boosters with either the Titan missile or a new custom booster stage to address a wide variety of launch weights. The smallest SLS vehicle consisted of a Titan and two strap-on solids, giving it performance similar to Titan C, allowing it to act as a launcher for Dyna-Soar. The largest used much larger solid-rockets and a much-enlarged booster for their direct ascent mission. Combinations in-between these extremes would be used for other satellite launching duties.