Countering postponements of launches in a four-launch Lunar landing mission scenario

Manned spaceflight is currently considering resumption of lunar missions. The national Lunar Program is being developed in Russia which will include a mission to a polar circumlunar orbit and humans landing on the lunar surface. Various mission scenarios are being considered for delivering humans to the lunar surface, including a two-launch scenario using super-heavy launch vehicles Yenisei, as well as a four-launch scenario based on heavy launch vehicles Angara A5V. The paper addresses in detail the four-launch lunar mission scenario, which includes delivery to the circumlunar orbit of a lunar ascent and descent vehicle and a crew transportation spacecraft with a crew onboard, as well as landing on the lunar surface. It provides an analysis of key trajectory constraints in this scenario and proposes an approach assuring that the mission is carried out even in case of postponements of launches of the transportation system elements.