ESPA On-orbit Maneuvering System (OMS)

Busek Co. Inc. is developing a Multi-Mode Orbit Maneuvering System (MMOMS) that can be added to ESPA ring, transforming it into a free-flying spacecraft that can deliver payloads to multiple orbits. In Phase I, we proved the feasibility of the concept and defined the architecture. The MMOMS has three sub-assemblies: The ESPA ring; the ESPA Propulsion Module (EPM), and the Power and Avionics Module (PAM). The EPM contains thrusters, power processors and conditioners, a propellant storage and distribution system, and a structure for mounting the hardware inside the ESPA ring. The PAM, to be sourced from DSX, occupies an ESPA payload interfaces, leaving room for five 181 kg payloads. The proposed EPM includes hydrazine thrusters for responsive maneuvering, and xenon Hall Effect Thrusters (HETs) for fuel efficient maneuvering. A near-COTS system would carry four BHT-200 thrusters, capitalizing on the success of TacSat-2. A more capable but lower TRL system would carry two BHT-1500 thrusters. In Phase II, we will develop prototypes for non-COTS hardware including a modular PPU and the BHT-1500, with a focus on improving system lifetime. Options are proposed to build the EPM structure and EM level hardware. At the conclusion of Phase II, the OMS hardware will be ready for qualification testing.