The Ignition Over Pressure, or IOP, is a principal dynamic load experienced by a launch vehicle during lift-off. The IOP arises due to the sudden ignition of the Solid Rocket Boosters(SRBs) of the launch vehicle. The present work attempts to simulate the ignition of a SRB with an impulsively started supersonic jet using a novel technique involving a quick open valve and a nozzle of Md=2.0 attached downstream. High speed Schlieren flow visualization is used to document the evolution of an impulsively started jet flow field that included the characteristic Precursor Shock Wave (that simulates the Blast wave causing the IOP) and the following Vortex Ring. The dynamic interactions between the impulsively started supersonic jet and an established steady, supersonic jet from another nozzle(Md=2.0) in close proximity, is also investigated. Both the precursor shock wave and the vortex ring, are observed to interact strongly with the established steady jet column as they proceed downstream from the nozzle exit, introducing new noise sources. When a generic jet blast deflector is introduced downstream of the nozzles, the precursor shock wave reflected from it, propagating upstream towards the nozzle exit. The reflected shock wave is recognized as the source of IOP experienced by the launch vehicle. The results show that the quick open valve presents a unique way to generate impulsively started jets for understanding transients associated with the ignition of the SRB leading to the IOP, without the complexity associated with the use of open ended shock tubes for carrying out such simulations. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.