It's hard to find anything about older programs, but they currently put a lot of work into simulators. https://www.nasa.gov/sites/default/files/ivv_grubb_nasa_

It's hard to find anything about older programs, but they currently put a lot of work into simulators. https://www.nasa.gov/sites/default/files/ivv_grubb_nasa_ivv_software_emulator_technology_portfolio_090114.pdf https://www.nasa.gov/sites/default/files/ivv_grubb_nasa_ivv_... On the other hand, at one time there was a physical "proof test model" of the Voyagers. https://www.jpl.nasa.gov/images/pia21734-voyager-test-model-configuration https://www.jpl.nasa.gov/images/pia21734-voyager-test-model-...