Space temperature traceability based on near-site transfer of miniature fixed points.

Long-term remote sensing precision depends on real-time radiation calibration, challenging the stability and accuracy of spaceborne calibrators in harsh space environments. Miniature fixed points offer a solution for International System of Units traceability of space radiation values. However, traditional in-situ calibration methods face difficulties due to location mismatches between miniature fixed points and radiation surface. We demonstrated a space temperature traceability technology, which realizes continuous temperature self-calibration across all-location region is achieved through near-site transfer mechanism of phase transition characteristics. A transfer link between fixed points-blackbody-remote sensor has been established. We further provided two traceability schemes and deployed eight miniature fixed points covering 234 K to 345 K. Experiments showed repeatability and long-term stability of 6.0 mK and 3.2 mK. Additionally, we exhibited the latest spaceborne blackbody, achieving the first on-orbit replication of 7.4 mK. This technology provides an effective on-orbit traceability path for long-term remote sensing monitoring.