Application of the Liquid Rocket Engine Test and Evaluation Standard to Risk-Tolerant Missions

The U.S. Space Force’s (USSF’s) most recent launch services procurement, designated Phase 3, defines a new “Lane 1” category for missions that are more risk tolerant than traditional National Security Space (NSS) missions, which are now designated “Lane 2”. Lane 1 missions are assigned to one of four tiers based on risk tolerance. All tiers except Tier 0, the highest-risk tier, require Launch Service Provider or Engine Developer to identify deviations from requirements in a mission-specific task order. For the propulsion subsystem, these requirements would typically include the USSF’s Evaluation and Test Requirements for Liquid Rocket Engines, SSC-S-025. This paper provides tailoring approaches to the engine standard SSC-S-025 so that it can be applied to Lane 1. A methodology for tailoring the requirements to account for higher risk tolerance is presented along with examples of tailoring.