Since the earliest days of astronautics, more than a century ago, low cost space launchers persevered to be a long desire for the space flight thinkers. Once space flight became a daily business along the late `50-s, first by consuming large financial resources, the interest for cheap space launchers became even more laud. Today’s growing interest in small satellites have bolstered a large series of space technology companies including Virgin Galactic Corp., Garvey Spacecraft Corp., Quantum Research International, Ventions LLC, Sierra Nevada Corp., Generation Orbit Launch Services and even the giant Boeing to work on the development of various types of such vehicles, some of them of actually small size. They have announced recent progresses in their efforts to develop and test small-satellite launchers and rocket engines. Romanian space launcher effort includes the NERVA project, with the ORVEAL compound engine for the upper stage, securing the orbital injection, project developed by the team of professors and researchers from ADDA Ltd, Bucharest. This project is based on a series of innovative concepts, including the optimal ascent program first proposed by the ADDA team by means of the new discontinuous variational optimization, which is here described in detail.