Junhui Meng
Beihang University
China
Title: Influences of initial launch conditions on flight performance of tethered stratospheric satellite
Biography
Biography: Junhui Meng
Abstract
The stratospheric satellite has attracted much attention due to its potential application in military and economy. In order to fulfill the tasks of a tethered stratospheric satellite, ascending process is an essential part of ballooning. During ascending, the lifting force is very sensitive to thermal effect. Both the balloon itself and the environment conditions affect ascending process. Among those factors, launch conditions are of vital importance due to their controllability. The initial launch conditions were classified into three types: inflating quantity, launch time and launch position. The ascending velocity and the differential pressure were defined and used as evaluation parameters of flight performance. To achieve better ascent performance, proper choices of launch conditions are required in the satellite mission preparation. In this paper, a novel dynamic model with thermal effects is addressed to describe thermodynamic and kinetic characteristics of the stratospheric satellite. Based on the model, ascending processes of a tethered stratospheric satellite under different initial launch conditions were simulated. Based on the dynamic simulation, influences of the trajectory control system on meridional migration of the stratospheric satellite are analyzed. It improves the controllability and security of the stratospheric satellite effectively. By using the iterative calculation of multi-body dynamics system, the equilibrium point of the stratospheric satellite is received. The computational accuracy is improved and the computational quantity is reduced enormously by setting initial values of several parameters in advance. Results showed that the inflating quantity is the most effective factor for ascending process, and the upper and lower limits were also proposed separately from safety and performance perspectives. For both launch time and launch location conditions, different solar radiation is the main effect approach during ascending process. Specifically, the influence mechanism of launch time in one day and launch longitude are completely identical due to the Earth’s rotation.