Liftoff Environments

Abstract

A Launch Environment, or Liftoff Environment, fundamentally represents a source of loading during the hold-down or liftoff phase of a rocket launch. A launch vehicle is subjected to transient and oscillatory pressure loading on its exterior surfaces induced by engines and boosters during vehicle hold-down and liftoff. These pressure loads are a principal source of structural vibration which may result in the malfunction of vehicle components or the fatigue of exterior skin panels or component brackets. Additionally, the pressure loading gives rise to sound pressure levels inside the crew cabin which may impact the crew's health, safety, or ability to communicate. Liftoff Environments can have a significant impact on the launch vehicle or surrounding structures. For SLS, there are eight primary environments supported by the Liftoff Environments team. These are Liftoff Acoustics (LOA), Hold-down Acoustics (HDA), RS-25 Nozzle Flow Transient (NFT) Acoustics, Booster Ignition Overpressure (IOP) & Duct Overpressure (DOP), Igniter Shock, Core Stage Engine (CSE) Overpressure, Excess Hydrogen (H2) Pop, and Infrasonic Acoustics. These can be split generally into acoustics, which are sustained stationary events, and transients, which are short duration nonstationary events.