Research status and prospect of space metrology

Here discuss the concept of Space Metrology, that is to assure unified system of unit and to guarantee an accurate and reliable measured value in space work which out of earth. For science aspect, the basic unit, such as time and frequency, length, temperature, electricity, and mass definitions need redefine. For technology and management aspect, measurement in long-time running on-orbit spacecrafts and space station, need re-calibrate periodically. The development situation of space metrology is introduced here. The development trends of space metrology are put forward as physical metric study, calibration in simulation space environment, standard in space, calibration for on-orbit sensors, gas sensors, and remote sensing, black box for standard transport, and space management.