Name: Pawan Kumar
Affiliation: Indian Institute of Astrophysics
Conference ID : ASI2022_750
Title : Dynamic performance verification of Visible Emission Line Coronagraph on-board Aditya L1 (VELC-L1) prototype.
Authors : Pawan Kumar S, Natarajan V, Nagabhushana S, S. Kathiravan, Suresh Venkata, Shalab Mishra, Kamath P U, Amit Kumar, Varun Kumar, Bhavana Hegde, Dasamantarao Utkarsha,Raghavendra Prasad B
Abstract Type: Oral
Abstract Category : Instrumentation and Techniques
Abstract : Visible Emission Line Coronagraph on-board Aditya L1 (VELC-L1) consists of 21optical assemblies, 4 detectors and 4 baffles. The payload volume is 1.71m (L) x 1.07m (W) x 0.540m (H). Payload global stiffness to be > 100 Hz to withstand the launch loads and the in-orbit thermal stresses should be minimal such that the performance is not compromised. The optical components are spread out over the optical bench of size 1.6m x 1 m. The overall mass budget of the payload is about 180 kg. There are 18 optical sub assemblies and 4 detectors systems populated on the optical bench. All the payload components should be aligned to tight tolerances (<20 arcsec) in order to meet the performance requirements. The VELC instrument is interfaced to spacecraft by 8 numbers of lugs using M6 bolts. Instruments together with all subassemblies intended to experience sine, & acoustic vibrations covering 5 to 100Hz and 5-2000 Hz respectively. The integrated performance before and after vibration is expected to remain unchanged to be qualified for launch. To arrive at this confidence each individual subsystems to be qualified in the similar manner independently. To evaluate the load spectrum to be impressed at the base of each sub-assemblies precisely, a mass inertial system made of Aluminium alloy is realised and tested. The resonant frequencies of individual sub assemblies and global stiffness is evaluated and compared with the analysis results to qualify the design. The alignment integrity is also tested pre and post vibrations which is found undisturbed. All the vibration and acoustic tests have been carried out at ISRO facilities. The relevant details and results of this activity are described the paper in detail.