ATMOSPHERIC RESEARCH WITH THE SMALL EXPENDABLE DEPLOYER SYSTEM - PRELIMINARY-ANALYSIS

Data on the structure of the lower thermosphere are extremely limited because of the inaccessibility of this region to research vehicles. Do wnward-deployed tethered satellites can provide access to this region of the atmosphere. A preliminary analysis of the potential use of the end mass of the Small Expendable Deployer System as a scientific platf orm for atmospheric and aerothermodynamic research is presented, To th is end, the deployment and attitude dynamics of the end mass during th e first mission have been numerically simulated. It is shown that meas urements of the atmospheric mean density with the end-mass onboard acc elerometers can be performed only in a short time interval around the orbit perigee; in addition, the analysis of the payload attitude dynam ics shows the need for attitude control. A preliminary analysis of end -mass attitude control techniques is then performed, Results show that the stringent attitude control requirements can be satisfied by activ e control devices.