Substantiation of the parameters of backup orbits during injection of the spacecraft in case of emergency conditions

When launching spacecraft (SC), abnormal situations arise due to a number of factors. As a result, part of the launches, which are recognized as partially successful, lead to the fact that the spacecraft are withdrawn and operate in “non-working” orbits. This situation leads to a decrease in the quality of the target task by a single spacecraft or spacecraft system. The article deals with the concept of substantiation of parameters, the so-called reserve orbits, which can be derived SC in the event of an emergency situation. Functioning in these orbits allows to provide the required level of performance of the target task. A method for solving the problem of substantiation of the parameters of reserve orbits of spacecraft systems for periodic review of a given surface of the Earth by selecting quasi-synchronous orbits with a shorter orbital period is proposed. The technique is based on a finite search of the entire set of quasi-synchronous orbits, which are as close as possible to the parameters of the regular target orbits. Priority is given to quasi-synchronous orbits with a period of rotation less than the period of rotation in the regular orbit, and providing the required bandwidth. The simulation results allowed us to formulate a number of important conclusions. Launched in emergency situations, the spacecraft reserve orbits significantly affect the characteristics of the earth’s surface viewing by the spacecraft system. In this case, the average values of the gap in the observation of the entire surface of the Earth remain, but the review of the Earth’s surface will not be as uniform as in regular orbits. This feature leads to the fact that the value of the maximum gap in the observation using reserve orbits will be equal to the maximum gap in the observation in the absence of one SPACECRAFT in the normal orbit, but in a short time interval.