Infrared spectral radiation fields observed by satellites make up an information-rich, multi-decade record with continuous coverage of the entire planet. As direct observations, spectral radiation fields are also largely free from uncertainties that accumulate during geophysical retrieval and data assimilation processes. Here, we present a tool called COSP-RTTOV for simulating satellite-like radiation fields within climate models. This tool enables new science applications in model evaluation, climate change detection, and satellite mission design and is especially valuable when users desire to avoid the assumptions and uncertainties inherent in satellite-based retrievals of geophysical variables or in atmospheric reanalysis.