# UVSQ-SAT, a Pathfinder CubeSat Mission for Observing Essential Climate Variables
## 6 Conclusions  
UVSQ-SAT is a scientific and technology demonstration satellite in the domain of Earth observation and solar physics, scheduled to be launched in 2020/2021. The main scientific goals are to measure the top of atmosphere outgoing longwave radiation and shortwave radiation and the solar spectral irradiance in the Herzberg continuum (200-242 nm) with good accuracy. UVSQ-SAT uses disruptive technologies for remote sensing and will improve the miniaturization and compactness of small sensors onboard small satellites. The UVSQ-SAT tools are used in our education program to train students in space technology, Earth observations, and astronomy and astrophysics. UVSQ-SAT represents a CubeSat of the INSPIRE series of satellite missions. The INSPIRE program is a multinational consortium of universities collaborating to develop a constellation of small satellites for cutting edge space and Earth science research, a supporting global ground station network, as well as research and educational programs covering spacecraft design, space systems engineering, operations, and data analysis. Currently, the UVSQ-SAT mission is not intended to provide a continuity of the essential climate variables' data records. However, the use of small compact space qualified sensors like those used in UVSQ-SAT can facilitate future innovative space programs onboard small satellites and the implementation of a future small satellite constellation dedicated to the measurements of the essential climate variables with full data traceability. The advantages of such a future constellation have been described in this manuscript and allow considering exceptional revisit time and spatial resolution, in particular for the Earth's energy imbalance monitoring. Indeed, a constellation of 50 satellites is needed to estimate global daily mean top of atmosphere outgoing longwave radiation and shortwave radiation. Moreover, this satellite constellation is the best way to observe diurnal cycles. These observations are more easily realized by flying the Earth radiation budget instruments on less expensive CubeSats than with classic satellites. Several UVSQ-SAT CubeSats represent a possible tool to meet the EEI global daily mean and the diurnal cycle. Conceptualization, M.M. ([PERSON]), L.D., P.K., S.B., A.S., A.H., E.B., S.A., C.D., P.G., L.L., A.J.-V., X.A., N.M., J.P.-C., T.L., G.P., D.R., P.B., E.S., F.T., A.P., K.S., A.B.A., M.M. ([PERSON]), C.M., A.L., C., A.C., P.-R.D., and A.B. ; science (climate studies and solar physics), M.M. ([PERSON]), L.D., P.K., S.B., A.S., A.H., and P.-R.D. ; hardware and engineering, M.M. ([PERSON]), E.B., S.A., C.D., P.G., L.L., A.J.-V., X.A., N.M., J.P.-C., T.L., G.P., D.R., P.B., E.S., F.T., A.P., K.S., A.B.A., M.M. ([PERSON]), C.M., A.A., L.C., A.C.; methodology, [PERSON] ([PERSON]); software, [PERSON] ([PERSON]), A.H., C.D., and A.J.-V.; formal analysis, [PERSON] ([PERSON]), L.D., P.K., S.B., A.S., and A.H; resources, [PERSON] ([PERSON]), L.D., P.K., S.B., A.S., A.H., E.B., S.A., C.D., P.G., L.L., A.J.-V., X.A., N.M., J.P.-C., T.L., G.P., D.R., P.B., E.S., F.T., A.P., K.S., A.B.A., M.M. ([PERSON]), C.M., A.A., L.C., A.C., P.-R.D., and A.B. ; writing, original draft preparation, [PERSON] ([PERSON]), L.D., P.K., S.B., A.S., and A.H.; writing, review and editing, [PERSON]. ([PERSON]), P.K., and S.B. ; project administration, M.M. ([PERSON]), L.D., P.K., S.B., A.S., A.H. and E.B. ; funding acquisition, M.M. ([PERSON]), P.K., A.S., L.D., and J.P.-C. All authors have read and agreed to the published version of the manuscript. This research was mainly funded by UVSQ (Universite de Versailles Saint-Quentin-en-Yvelines, France), Agence Nationale de La Recherche (ANR, France), and Centre National de la Recherche Scientifique (CNRS, France).