## 6 Conclusions  
The UVSQ-SAT mission was launched in January 2021. Since February 2021, the satellite has been observing the Earth and the Sun. The first results were obtained using  
Figure 16: UVSQ-SAT and its potential future satellites constellation named Terra-F.  
the methods described by [PERSON] et al. (2020) [1]. These results are very encouraging and clearly show that small satellites represent a fast method to answer key scientific questions. In the era of NewSpace, i.e., an era benefiting from technological advances in miniaturization and reasonable costs to access space, this mission clearly shows that a constellation of small satellites dedicated to the measurement of the EEI is feasible. At a time when the climate emergency is obvious and the signals of global warming of the Earth are largely above the level of natural variability, one of the greatest challenges remains the difficulty of obtaining adequate funding for research and especially for missions dedicated to the study of climate (EEI at the TOA, spectral solar irradiance, vertical temperature profile, ozone, aerosols, etc.). These missions must rely on the implementation of satellites constellation to ensure sufficient spatial and temporal coverage. Satellites constellation dedicated to the study of climate and science are now a matter of course [21]. The UVSQ-SAT prototype opens the way to a potential Terra-F constellation composed of 50 small satellites with the necessary performance to meet the scientific need. Other solutions to measure the EEI are possible with two \"traditional\" satellites placed at the L1 and L2 Lagrange points in order to make measurements of our planet on the illuminated and non-illuminated portions. The main goal is to make measurements of the EEI at the TOA and its variability in time in order to detect any long-term global trend with a stability of at least \(\pm 0.2\) Wm\({}^{-2}\) per decade but also to be able to obtain spatial resolutions of a few tens of km and temporal resolutions of three hours with an accuracy of a few Wm\({}^{-2}\). These measurements must be performed on wide wavelength bands. Today, it is becoming increasingly clear that small satellites are not only a fast way to answer key scientific questions but also contribute qualitatively to scientific research. Conceptualization, M.M. ([PERSON]), T.B., C.D., A.H., P.K., A.F., S.B., S.A., E.B., L.D., J.-L.E., P.G. ([PERSON]), P.G. ([PERSON]), L.L., A.S., A.-J.-V., P.L., X.A., O.H.F.d., A.M., J.-P.C., F.B., M.M. ([PERSON]) and C.M. ; Data curation, [PERSON] ([PERSON]), T.B., C.D., A.H., A.F. and N.C.; Formal analysis, [PERSON] ([PERSON]), T.B., C.D., A.H. and A.F. ; Funding acquisition, [PERSON] ([PERSON]); Investigation, [PERSON] ([PERSON]), E.B., P.L. and N.C.; Methodology, [PERSON] ([PERSON]), T.B., C.D., A.H., P.K., A.F., S.B., S.A., L.D., J.-L.E., P.G. ([PERSON]), P.G. ([PERSON]), L.L., A.S., A.-J.-V. and X.A. ; Project administration, [PERSON] ([PERSON]); Resources, [PERSON] ([PERSON]); Software, [PERSON] ([PERSON]). T.B., C.D., A.H., P.K. and A.F. ; Supervision, [PERSON] ([PERSON]); Validation, [PERSON] ([PERSON]), T.B. and C.D. ; Visualization, [PERSON] ([PERSON]), T.B., A.H. and A.F. ; Writing--original draft, [PERSON] ([PERSON]), T.B., C.D., A.H., P.K., A.F., S.B., S.A., E.B., L.D., J.-L.E., P.G. ([PERSON]), P.G. ([PERSON]), L.L., A.S., A.-J.-V., P.L., N.C., X.A., O.H.F.d., A.M., J.-P.C., F.B., M.M. ([PERSON]) and C.M. ; Writing--review and editing, [PERSON] ([PERSON]), T.B., C.D. and A.H. All authors have read and agreed to the published version of the manuscript. This research was mainly funded by Centre National de la Recherche Scientifique (CNRS, France), Universite de Versailles Saint-Quentin-en-Yvelines (UVSQ, France), and Agence Nationale de la Recherche (ANR, France). This work was supported by the Programme National Soleil Terre (PNST, France) of CNRS/INSU (France) co-funded by Centre National d'Etudes Spatiales (CNES, France) and Commissariat a l'energie atomique (CEA, France).