SOLAR TOTAL IRRADIANCE VARIABILITY FROM SOVA-2 ON BOARD EURECA

The solar total irradiance has been measured during the EURECA (EUropean Retrievable CArrier) mission by the radiometers PMO6 of the experiment SOVA 2 (SOlar VAriability, Experiment 2). The instruments are of the active cavity type with a sampling of 99 s. Their specification and behavior in space are described. The time series of total irradiance gathered with the radiometers covers 9 months, starting in August 1992. Solar variability on time scales from minutes to the mission duration except for the periods close to the orbit around the Earth is observed. The results are correlated with the Photometric Sunspot Index (PSI) and compared with results from other experiments.