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Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m(2) with high accuracy and the response time of less than 10 s.

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A heat flux meter calibration system composed of a vacuum cryogenic container, a blackbody furnace and a set of T-type thermocouples measurement system is introduced in this paper. Primary purpose of this system is to calibrate specific heat flux meters applied in spacecraft thermal ground tests within which the heat flux range is from 60w/m 2 to 1400w/m 2 and vacuum is necessary. To simulate space condition, the vacuum container is designed according to the space simulator working standard in thermal ground tests. The required temperature measurement uncertainty in the heat flux meter calibration system is less than 0.1K and thermocouple calibration is completed in a more precise thermostatic bath of uncertainty less than 3mK. Thermal character of the vacuum container and the blackbody furnace are verified by NX IDeas simulations. Besides, Heat flux distribution non-uniformity of the blackbody furnace aperture is 3.5% and obtained by ray trace method. Consequently, heat flux meter calibration uncertainty less than 5% is proved to be realizable in this system.