Boilerplate Apollo capsule

A boilerplate spacecraft, also known as a DemoSat or mass simulator, is a nonfunctional craft or payload which is used to test various configurations and basic size, load, and handling characteristics of rocket launch vehicles. It is far less expensive to build multiple, full-scale, non-functional boilerplate spacecraft than it is to develop the full system (design, test, redesign, and launch). In this way, boilerplate spacecraft allow components and aspects of cutting-edge aerospace projects to be tested while detailed contracts for the final project are being negotiated. These tests may be used to develop procedures for mating a spacecraft to its launch vehicle, emergency access and egress, maintenance support activities, and various transportation processes.