The paper presents features of the design and ballistic parameters of the modern foreign small-lift launch vehicles pertaining to the ultra-light and light classes according to the Russian classification system. It examines their relative alteration compared to the previously developed vehicles with the similar dimensions. The paper analyzes alteration in the payload fraction compared to the heavier launch vehicles, and clarifies the main reasons for these fractions decrease due to the scale factor influence. Analysis of statistical dependencies for the previously developed vehicles reveals that for the liquid-propellant rocket engines and stages, mass perfection is decreasing nonlinearly with the decreasing mass, while it remains constant on averagefor the solid-propellant stages. Moreover, significant improvements are observed with the modern liquid launch vehicles only in mass perfection of their first stages, while parameters of the second stage and the engines used are remaining at the previously achieved levels. Payload fractions in the reference and sun-synchronous orbits differ insignificantly against the foreign small-lift launch vehicles and, for example, the Zenit-2 medium-heavy launch vehicle. The most significant factor causing this fraction to decline is decreasing performance of the liquid-propellant rocket engines with the reduced thrust, which is compensated by the increasing mass improvement of the rocket units and reducing the load on the mid-section.

 EDN URIJOI