Radiometric measurements of directional albedo of the earth requires a detector with flat response from 0.2 to 50 microns, response time of less than a second, a sensitivity of at least 0.1 mv per mw/cm2, and with a measurement uncer-tainty of less thab 1% absolute cavity radiometers easily meet the spectral response and accuracy requirements for earth albedo measurements, but the radiometers available today lack the necessary sensitivity and response time characteristics. The specific innovation to be addressed in this effort is the use of a very low thermal mass cavity and printed/ deposited thermocouple sensing elements incorporated into the proven kendall black body radiometer design to produce a sensitive,fast response,absolute radiometer. The new un- it would be applicable to the measurement of the reflected and radiated fluxes from the earth's surface and lower at- mosphere from low earth orbit satellites. The effort will consist of requirements and thermal analysis, design and construction,and test of prototype, proof-of-operation, el- ements of the black cavity and sensor elements. Two potential commercial applications; surface and sky radi-
