Roll torque analysis for a solid-propellant single-body Launcher
- Paper number
IAC-08.C4.2.11
- Author
Mr. Lorenzo Bisi, Italian Space Agency (ASI), Italy
- Coauthor
Mr. Aldo Scaccia, Italian Space Agency (ASI), Italy
- Coauthor
Mr. Daniele Barbagallo, European Space Agency (ESA), Italy
- Year
2008
- Abstract
In view of VEGA Launcher qualification flight, the ASI (Italian Space Agency) Space Transportation Unit technical team has set out an extensive work on roll torque onset, being VEGA a roll-free, single-body launcher. The first step has consisted of an exhaustive collection and analysis of roll sources in Launch Vehicles (for instance, the aerodynamic effects due to CoG offset and mounting misalignments), which highlighted that a non negligible contribution results from the solid rocket motors. As a consequence, we focused our investigation on the phenomena occurring in the combustion chamber of a solid rocket motor, what is referred to as Type II roll, according to Knauber. After reviewing data from literature an innovative semi-empirical scaling law has been elaborated, in order to provide a preliminary estimate of peak roll value. Light has been shed on the relationship between propellant grain geometry evolving in time and roll. Our analytical evaluation is being supported by CFD simulations and post-processing of VEGA SRM’s Static Firing Test data. The major outcome of our analysis is the dependence of roll torque on the starred portion of propellant grain. Moreover, we discovered that roll can only occur during combustion time of starred region and that the angular impulse is not so significant, in spite of high peak values. In conclusion, we can state that the launcher can be roll-controlled even in case of estimated roll torque peaks produced by the motor being higher than the control system counteracting capability.
- Abstract document
- Manuscript document
IAC-08.C4.2.11.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.