When developing new astronomical instruments, there is a need to perform the characterization of their individual components, especially the detectors, to ensure that their performances comply with the scientific objectives of the instrument. A visible-near infrared (VIS-NIR) facility was developed for the absolute and relative radiometric characterization of space-based detectors at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB). The facility operates from 0.4 to 2.65 μm in an ISO-5 environment. It offers a tunable monochromatic flux with a high level of straylight rejection (10 − 8) and 2% uniformity, over a four-decade range of intensity with adjustable bandwidth. Latency measurements are also possible. Thermalization is offered within a precision of 7 mK between 50 K and 382 K. The ultimate vacuum level of the detector chamber is below 10 − 6 mbar. A robust security system avoids both reaching temperatures outside the operational range of the detector and its electronics, and contamination due to vacuum loss. The facility was already used to characterize the VIS-NIR detectors of the Moons And Jupiter Imaging Spectrometer (MAJIS), one of the instruments on board the Jupiter ICy Moons Explorer (JUICE). The versatility provided by the VIS-NIR facility allows its use for the characterization of other astronomical detectors.