Space-based servicing

On-orbit servicing of spacecraft and payloads is one of the most viable economic justification for a permanent, manned space station. Services include the changeout of Orbital Replaceable Units (ORU's), the replenishment of consumables, general maintenance, on-orbit assembly and repair of failures. Among economic and operational advantages are: longer spacecraft operational lifetime; lower acquisition cost of satellites; improved spacecraft performance. A comparison is made between space station and shuttle-based servicing.