SOLCON solar constant observations from the ATLAS missions

The solar constant observations obtained by the SOLCON/ATLAS experiment during the three successive missions are presented based on the Space Absolute Radiometric Reference (SARR) defined during the ATLAS-2 mission. The objectives of SOLCON, namely to obtain accurate measurements of the solar constant and to compare them with the observations obtained from free flyers in the hope of establishing a baseline and strategy for monitoring the solar constant at climate scale, have been achieved successfully with the three ATLAS missions. The long range objective of insuring the solar constant data continuity will, however, require that an alternative approach than that of the ATLAS program be found to fly and retrieve SOLCON.