ISS: On-Board ECLSS Maintenance Activities and Launch Logistics

The ISS U. S. ECLSS contains replaceable component designs to facilitate maintenance. A replaceable component is referred to as an Orbital Replacement Unit (ORU). Total U. S. ECLSS maintenance events that have occurred over the five years (2001-2005) of operations are summarized. A more detailed description is provided for the ECLSS Remove and Replace (R&R) maintenance activities that have occurred during the last two years and the associated logistics that supported these activities. Maintenance activities have replaced failed or degraded ORU's by Corrective Maintenance (CM) and replaced spent expendable ORU's by Preventative Maintenance (PM). Corrective maintenance is performed only when necessary and often on relatively short notice. Preventative maintenance is planned in advance and is normally performed at a specified ORU service time. The paper also describes activities and successful efforts to increase the expendable ORU service life. Other maintenance activities, besides R&R, are scheduled inspections, cleaning and periodic rotation of idle equipment. ECLSS logistics metrics such as Shuttle, Progress and Soyuz launched and returned quantities, weights and volumes are presented. Future planned maintenance activities and logistics are discussed as well as planned changes to ORU designs and service life.