Estimation of an opportunity of Mercury mission with use of solar electric propulsion

Abstract

Estimation of transport opportunities of delivery of a research spacecraft (SC) to Mercury with the use of launcher “Proton”, chemical upper stage (ChUS) as “D” and solar electric propulsion upper stage (SEPS) on the basis of thrusters ESA-XX and SPT is analyzed. It is assumed that Russian launch vehicle “Proton” and upper state “Block D” deliver a spacecraft into the geocentric hyperbolic orbit. Then “Block D” is separated. The heliocentric arc of the trajectory and operations in the vicinity of Mercury are supported by SEPS. It is supposed, that the change of SEPS thrust value according to available electrical power occurs due to change in propellant (Xenon) flow rate. The problem was formulated as follows. For the known characteristics of the ChUS, the SC and its systems are required to determine the unknown design SC parameters, circuit of transfer and control program of a thrust vector, ensuring delivery in the vicinity of Mercury of maximum SC mass at a given transfer duration. Chosen parameters and control functions are: mass of ChUS propellant (or value of hyperbolic excess velocity connected with it), direction of hyperbolic excess velocity, launch date, the control program of the thrust vector of the ion-engine (orientation of a thrust vector, moments of the engine firings and shut-down).