Vol 57, No 5 (2019)

The paper presents the results of the investigation of the possibility to develop a stationary plasma thruster with increased thrust. This research was carried out by the Research Institute of Applied Mechanics and Electrodynamics, Moscow Aviation Institute (RIAME MAI) jointly with Fakel Design Bureau as an industrial partner. During research, we developed and investigated a laboratory model, prototype, and experimental model of the SPT-100VT thruster, whose main dimensions are close to those of the well-known SPT-100 serial thruster, which is produced by the Fakel Design Bureau and is successfully operating in space. As a result, it has been shown that the SPT-100VT thruster can effectively and for a long time operate with a discharge voltage of 300 V and power of up to 3 kW producing thrust more than twice that of the SPT-100 with a thrust efficiency above 60% and specific impulse over 1800 s. The increased thrust is achieved by an increase in the xenon flow rate; the efficiency of the thruster is increased due to the modernization of the thruster magnetic system and geometry of the accelerating channel.

A complete cycle of studies is considered, which are related to obtaining knowledge on spectral and time-response characteristics of emission from stationary plasma thrusters (SPTs), to the development of mathematical and simulation models of such emission, and assessment of its influence on the interference immunity of space communication systems. The reliability of data transmission via Earth–spacecraft digital communication channels is assessed based on the results of simulation modeling. The bit error rate is studied as a function of signal-to-noise and signal-to-SPT-interference ratios. Power loss of the communication channel in the presence of SPT emission relative to the standard system is considered as its interference immunity indicator. Calculations are made for the power budget of deep- and near-space radio links. Power loss is assessed for the Earth–Mars radio links and within the geostationary orbit. Recommendations on reducing the SPT emission effect are presented.

A technique of searching for optimal trajectories with gravity assisted maneuvers (GAMs) for interplanetary transfers of spacecraft (SC) with an electric propulsion system (EPS) is proposed. In this case, the indirect optimization method is used. A distinctive feature of this technique is the combination of optimality conditions at the point of GAMs within a single boundary value problem for two cases, when the height of the flyby hyperbola with the GAM is less than or equal to the maximum one. This approach makes it possible to considerably reduce the volume of necessary calculations in optimizing SC interplanetary trajectories that include GAMs. It considers end-to-end trajectory optimization with an analysis of the full set of optimality conditions at the point of the GAM. The efficiency of the proposed approach is demonstrated by the example of optimization of interplanetary trajectories from Earth to Mercury with a GAM in the vicinity of Venus and from Earth to Jupiter with a GAM near Earth.

A method of reducing the radiation power degradation of spacecraft solar array during combined geostationary orbit insertion using a booster and an electric propulsion system is considered in this paper. The essence of the method is to optimize the shape of the transfer trajectory and the perigee argument of the intermediate orbit. The maximum principle is applied to the problem of optimizing the SA electrical power at the end of 15 year spacecraft’s operational lifetime (EOL). For this, the equation for the current SA power and the constraint on this power at the EOL is added to the equations of spacecraft motion. The closed-form solution to the adjoint equation to SA power is obtained. Calculation of SA radiation degradation was carried out using the models of charged particle fluxes of Earth’s radiation belts, AE8 MAX and AP8 MAX. To increase the EOL SA power by 0.16–0.66% of the SA power at the beginning of the transfer depending on the parameters of intermediate orbits. The additional characteristic velocity increased relative to the minimum time trajectories by 13–1087 m/s depending on the parameters of intermediate orbits.