VEGA Stages Full Scale Separation Test: Simulation, Preparation and Results
- Paper number
IAC-06-D2.5.10
- Author
Dr. Marino Fragnito, ELV S.p.A, Italy
- Coauthor
Mr. Fabrizio Barbieri, ELV S.p.A, Italy
- Coauthor
Mr. Cristiano Contini, ELV S.p.A, Italy
- Coauthor
Mr. Josè Luis Leofanti, ELV S.p.A., Italy
- Coauthor
Mr. Matteo Monterosso, ELV S.p.A., Italy
- Coauthor
Mr. Michel Bonnet, European Space Agency/ESRIN, Italy
- Coauthor
Mr. Andrea Preve, Italy
- Year
2006
- Abstract
In the frame of VEGA Launch Vehicle development program, a full scale test has been prepared and successfully performed to verify the correct separation of 2nd and 3rd stage and to acquire fundamental objectives such as: - Verification of correct functionality of pyrotechnical separation system at full scale, - Verification of correct separation, - shock characterization, - verification of layout and equipment qualification versus shock environment, - acquisition of data to support the kinematics analysis of flight separation phase. The article tested was the interstage between the 2nd and 3rd stage Solid Rocket Motors, consisting of a stiffened cylindrical structure about 2 m height per 2 m diameter implementing a pyro-cord actuated system cutting a 3 mm thick flange to separate and free the launch vehicle of the expended stage. In this structure different equipments are installed with the related harness, in particular in the upper part (3rd stage) the Thrust Vector Control Batteries and Integrated Power Distribution Unit are implemented. On the upper part of the interstage, the bottom part of the third stage motor was represented by a mock-up to better simulate the boundary conditions and to provide the right interfaces to the Electro-Mechanical Actuators, whose environment has also been characterised. The correct separation and distancing of the two separated parts is ensured by eight springs actuated mechanism, with a rather high stored energy. In the test, the upper part (3rd stage) was fixed to a hard mounted stand, while the separated lower part was accelerated down, on a recovery damping system, by the action of these mechanisms. The simulation of the test, performed in order to predict the test results and install and calibrate measurements, was very difficult because of the multiple events occurring in the very short time characterizing the separation (few milliseconds): typical pyroshock loadings are, in fact, simultaneous with low frequency loadings, due for instance to the structure relaxation from the springs pre-loading, and of course global kinematics also occur at the same time. Furthermore, interstage separation mechanism was as per flight configuration, while mass and inertia of test article were much lower than flight stages; this generated more than 3 times faster kinematics difficult to be acquired and correlated with predictions. This paper describes how the test was prepared and carried out, showing interpretation and correlation by analysis of the most important phenomena occurring.
- Abstract document