Vehicle Engineering Aspects of Interfacing S200 Strapon Boosters in LVM3
- Paper number
IAC-07-C2.1.02
- Author
Mr. S. Somanath, Indian Space Research Organisation (ISRO), VSSC, India
- Coauthor
Mr. Surendar Vir Sharma, Indian Space Research Organisation (ISRO), VSSC, India
- Year
2007
- Abstract
GSLV MkIII (LVM3) configuration is defined as 2S200+L110+C25, where S200 is the solid strap-on booster, L110 is the earth storable liquid booster and C25 is the cryogenic upper stage. S200 is connected to the core through a single forward thrust transfer interface and three separable links at the aft end. The separable forward interface is in the Nose Cone Adaptor (NCA) structure of S200. This is connected to IS1/2U, the structure between L110 and C25 stages. The S200 stage is provided with a Thrust Oscillation Isolation System (TOIS) inside the NCA. The design of these interfacing elements required satisfying many conflicting constraints. The challenge was in containing the displacements, loads in adjacent hardwares and stresses in each of these systems meeting the mass budget. This paper describes the system engineering and design issues in the structural systems and qualification of these hardwares. The attachment interface located at the aft of NCA and on IS1/2U close to the cryo stage created difficulty in load diffusion to adjacent structures. IS1/2U is a skin stiffened structure. The axial load transferred at this interface from S200 is the net inertial load. The lateral loads due to the thrust offset, aero loads on S200 and control also received here. The load is transferred to the adjacent structures limiting the interface loads and displacements. Since L110 stage is not thrusting, the inertial loads are tensile. The structure above IS1/2U is the Aft Stub Adaptor (ASA) with separation system for L110 stage based on collet mechanism. The loads on the ASA truss members are controlled by the stiffness and displacement of IS1/2U and LOX tank. The interface loads and displacements are contained within the acceptable limits of the separation mechanism. Using the predicted chamber pressure oscillations of S200 motor, response analysis on LVM3 gave unacceptable response at the spacecraft interface. The TOIS is provided to alleviate this problem. The TOIS is based on elastomeric modules. The design of TOIS is further constrained by the displacements and rotations at the S200 interface permitted by the separation system. The separation system for S200 is based on pyro bolts which is severed using circular Flexible Linear Shaped Charge (FLSC). The design is based on the ISRO’s proven linear FLSC systems. The attachments links at the aft side also uses identical pyro system for cutting the links. Structural testing of IS1/2U, ASA and LOX tank is one of the unique testing schemes incorporating all hardwares in a single test configuration and simulating the interface loads simultaneously. The vehicle engineering of the interfacing S200 strap-on boosters in LVM3 was one of the demanding design issue tackled. The hardwares were concurrently designed meeting many interface, structural and functional requirements. Integrated finite element analysis incorporating all hardware components were resorted to find the solutions. The analysis models were tested in multiple platforms and validated before the acceptance of the designs.
- Abstract document
- Manuscript document
IAC-07-C2.1.02.pdf (🔒 authorized access only).
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