AN OVERVIEW OF THE LAUNCH VEHICLE BLAST ENVIRONMENTS DEVELOPMENT EFFORTS Erin Richardson NASA MSFC EV33 Huntsville, AL Mike Bangham, James Blackwood, Troy Skinner, Michael Hays, Austin Jackson, Ben Richman Bangham Engineering, incorporated Huntsville, AL ABSTRACT NASA has been funding an ongoing development program to characterize the explosive environments produced during a catastrophic launch vehicle accident. These studies and small-scale tests are focused on the near field environments that threaten the crew. The results indicate that these environments are unlikely to result in immediate destruction of the crew modules. The effort began as an independent assessment by NASA safety organizations, followed by the Ares program and NASA Engineering and Safety Center and now as a Space Launch Systems (SLS) focused effort. The development effort is using the test and accident data available from public or NASA sources as well as focused scaled tests that are examining the fundamental aspects of uncontained explosions of Hydrogen and air and Hydrogen and Oxygen. The primary risk to the crew appears to be the high-energy fragments and these are being characterized for the SLS. The development efforts will characterize the thermal environment of the explosions as well to ensure that the risk is well understood and to document the overall energy balance of an explosion. The effort is multi-path in that analytical, computational and focused testing is being used to develop the knowledge to understand potential SLS explosions. This is an ongoing program with plans that expand the development from fundamental testing at small-scale levels to large-scale tests that can be used to validate models for commercial programs. The ultimate goal is to develop a knowledge base that can be used by vehicle designers to maximize crew survival in an explosion. INTRODUCTION The Launch Vehicle Blast Environments study is an ongoing effort to characterize the environments resulting from catastrophic launch vehicle explosion. The purpose is to develop the data and information required to allow launch vehicle and crew systems designers to develop safer crewed launch systems. This paper is a high level summary of the activities, early results and plans of the project. Detail data is provided in a series of papers that address both the liquid propellant launch vehicles and solid boosters. The more detailed papers address the blast physics, the fragments that are generated and accelerated and the thermal aspects of the explosions that can be produced. The effort is continuing but some early observations can be made about how they might impact future vehicle designs. This work is focused on the near field effects of the explosions. This is the least studied region and is of direct influence to the crew. Higher fidelity analysis is required to adequately define the risk to the crew and to understand possible impacts to the crew systems involved in protecting and rescuing the crew. All phases of the ascent are being addressed but current efforts have focused on the pad and near pad regions since there is more data available and the magnitude of the blast overpressures is increased due to ground reflections. These results can be used to inform the ground environments but additional work is required to ensure the safety of ground crews due to the susceptibility of unprotected humans to the environments.