AEROSPACE REPORT NUMBER: TOR-2010(8591)-19, OBJECTIVE CRITERIA FOR HERITAGE HARDWARE REUSE (30-JUN-2010)

AEROSPACE REPORT NUMBER: TOR-2010(8591)-19, OBJECTIVE CRITERIA FOR HERITAGE HARDWARE REUSE (30-JUN-2010)., Developers of space flight equipment often look for opportunities to reuse heritage hardware (previously qualified space flight hardware) as opposed to developing new equipment. Based on the existing knowledge of the heritage hardware, reuse can provide benefits to the development effort such as reduced risk due to fewer “unknown-unknowns” and reduced development activity (design, fabrication, verification), which can translate into decreased development cost, schedule, and contingencies (interfaces, mass, volume, power, environmental). Due to these benefits for complex high-reliability space flight equipment developments, heritage hardware reuse planning and processes should be an integral part of the space flight development process. However, heritage hardware reuse needs to be treated with caution for several reasons. Reusing existing hardware, equipment and/or designs can constrain the design options at the next higher level of integration; i.e., interfaces. Also, reuse decisions are typically made early in the development process, often prior to system level preliminary design, before requirements have been finalized. As a result, the development planning may assume reuse benefits that are not realized due to subsequent system level design. This can result in inadequate resources identified for heritage hardware re- design, rework, and re-verification needed to accommodate the maturing design. This can lead to programmatic issues (increased cost and schedule), high risk technical compromises, or both. Finally, if the reuse decision is not revisited as the system level development matures, then needed heritage hardware modifications may not be identified, resulting in technical deficiencies that may not be identified until the next level of integration or, of more concern, on orbit. To help mitigate these concerns associated with heritage hardware reuse, several aerospace organizations collaborated to generate this guideline document, which describes objective criteria for heritage hardware reuse. These objective criteria are presented in the form of a Heritage Readiness Level (HRL) Scoring Matrix. This tool is intended for use by those involved in heritage hardware reuse during space flight development and is based on industry best practices. This document focuses on the reuse of space flight units that have been successfully qualified and used on previous missions i.e., a functional replaceable unit made up of units and delivered for integration. These guidelines are intended to be used by those responsible for delivering the flight unit, as well as the customers and integrators of the flight unit.