System Safety Design Considerations for Cryogenic Payload Servicing at Kennedy Space Center

Abstract

Shuttle missions that use cryogens typically require periodic servicing at Kennedy Space Center (KSC) prior to launch Cryogenic operations have unique handling requirements that need to be considered to maintain a safe environment. The KSC facilities have stringent safety requirements for flight hardware and Ground Support Equipment (GSE) documented in KHB 1700 7B1. The Superfluid Helium On-Orbit Transfer (SHOOT) payload flew on June 21 through June 30, 1993 on STS-57 to demonstrate cryogenic technology in space for supporting replenishment of liquid helium in spacecraft. The SHOOT Payload requires periodic filling of flight dewars with liquid helium and near-superfluid helium before launch. It has been approved for processing at KSC by the Safety Review Panel. This paper covers KSC safety requirements for cryogenic operations and specific steps taken to qualify the SHOOT payload flight hardware and GSE by meeting design, testing, and inspection safety requirements. This includes operational safety concerns and precautions taken to prevent rupture of cryogenic dewars and GSE system, asphyxiation, and cold temperature exposure of personnel. Procedural requirements are addressed for servicing set-up, operation, and disassembly of helium transfer operations. Lessons learned are included based on recent experiences gained at KSC.