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A space spectrograph main structure is optimized and examined in order to satisfy the space operational needs.
The space spectrograph will be transported into its operational orbit by the launch vehicle and it will undergo
dynamic environment in the spacecraft injection period. The unexpected shocks may cause declination of
observation accuracy and even equipment damages. The main frame is one of the most important parts because its
mechanical performance has great influence on the operational life of the spectrograph, accuracy of observation, etc.
For the reason of cost reduction and stability confirming, lower weight and higher structure stiffness of the frame are
simultaneously required. Structure optimization was conducted considering the initial design modal analysis results.
The base modal frequency raised 10.34% while the whole weight lowered 8.63% compared to the initial design.
The purpose of this study is to analyze the new design of main frame mechanical properties and verify whether it
can satisfy strict optical demands under the dynamic impact during spacecraft injection. For realizing and forecasting
the frequency response characteristics of the main structure in mechanical environment experiment, dynamic
analysis of the structure should be performed simulating impulse loads from the bottom base. Therefore, frequency
response analysis (FRA) of the frame was then performed using the FEA software MSC.PATRAN/NASTRAN.
Results of shock response spectrum (SRS) responses from the base excitations were given. Stress and acceleration
dynamic responses of essential positions in the spacecraft injection course were also calculated and spectrometer
structure design was examined considering stiffness / strength demands. In this simulation, maximum stresses of
Cesic material in two acceleration application cases are 45.1 and 74.1 MPa, respectively. They are all less than yield
strengths. As is demonstrated from the simulation, strength reservation of the frame is adequate, but amplitudes of
some key positions' dynamic responses are numerically too high. It need be emphasized in the next stage of design
and experimental research.
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