Observations of the solar spectral irradiances from satellites, rockets and balloons, in addition to ground level and aircraft measurements, are of fundamental importance for a correct interpretation of aeronomic phenomena in the terrestrial and planetary atmospheres. An analysis of the limited amount of published data on the full-disk solar fluxes indicates clearly that more simultaneous and continuous measurements are needed to reduce the systematic differences between the various observed spectral irradiances. It is also important to reduce by precise calibrations the multiple random errors in order to permit meaningful studies of the variability of the solar fluxes. Permanent support by Space Agencies for multiple and long-term observations is required for the acquisition of a reliable data base of accurate spectral solar irradiances.