Separation dynamics of heat shield fairings

The dynamics associated with the jettisoning of heat shield fairings from the parent launch vehicle is investigated. The analysis considers a zip-cord based mechanism employed to jettison the fairings from the accelerating on-going stage. A scheme for characterization of the zip-cord system is described. The geometry of collision is analysed for a known, precomputed structural response. The no- collision domain is constructed in flexibility parameter space for an arbitrarily assumed impulse level. Alternatively, the minimum impulse required for a collision-free separation is also computed as a function of design parameters. Finally, the analysis enables generation of the upper limits on payload size as well as that of the external mountings for a clean separation. This methodology has led to the successful separation of shield heat fairings for the two developmental flights of the Indian launcher Polar Satellite Launch Vehicle (PSLV).