# UVsq-Sat NG, a New CubeSat Pathfinder for Monitoring Earth Outgoing Energy and Greenhouse Gases
## 2 Scientific Objectives
### Earth's Radiation Budget
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Requirements for Uvsq-Sat—Launched on 24 January 2021 from Cape Canaveral, Florida, USA** \\ \hline ECV & Absolute accuracy & Stability per year & Spatial resolution & Temporal resolution (global map) \\ \hline OSR & \(\pm\)10.00 Wm\({}^{-2}\) & \(\pm\)5.00 Wm\({}^{-2}\) & 2500 km per element & 30 days with one CubeSat \\ OLR & \(\pm\)10.00 Wm\({}^{-2}\) & \(\pm\)1.00 Wm\({}^{-2}\) & 2500 km per element & 30 days with one CubeSat \\ \hline \multicolumn{5}{c}{**Requirements for Inspire-Sat7—Launched on 15 April 2023 from Vandenberg, California, USA**} \\ \hline ECV & Absolute accuracy & Stability per year & Spatial resolution & Temporal resolution (global map) \\ \hline OSR & \(\pm\)5.00 Wm\({}^{-2}\) & \(\pm\)1.00 Wm\({}^{-2}\) & 2500 km per element & 10 days with two CubeSats \\ OLR & \(\pm\)5.00 Wm\({}^{-2}\) & \(\pm\)1.00 Wm\({}^{-2}\) & 2500 km per element & 10 days with two CubeSats \\ \hline \multicolumn{5}{c}{**Requirements for Uvsq-Sat NG—Launch Date in 2025 or in 2026**} \\ \hline ECV & Absolute accuracy & Stability per year & Spatial resolution & Temporal resolution (global map) \\ \hline OSR & \(\pm\)3.00 Wm\({}^{-2}\) & \(\pm\)1.00 Wm\({}^{-2}\) & 2500 km per element & 5 days with three CubeSats \\ OLR & \(\pm\)3.00 Wm\({}^{-2}\) & \(\pm\)1.00 Wm\({}^{-2}\) & 2500 km per element & 5 days with three CubeSats \\ CO\({}_{2}\) & \(\pm\)4.0 ppm & \(\pm\)1.0 ppm & 2–10 km per pixel & \(>\)30 days \\ CH\({}_{4}\) & \(\pm\)25.0 ppb & \(\pm\)10.0 ppb & 2–10 km per pixel & \(>\)30 days \\ \hline \multicolumn{5}{c}{**Requirements for a Hypothetical Satellite Constellation Named Terra-F—Horizon 2035**} \\ \hline ECV & Absolute accuracy & Stability per decade & Spatial resolution & Revisit time \\ \hline TSI & \(\pm\)0.54 Wm\({}^{-2}\) & \(\pm\)0.14 Wm\({}^{-2}\) & – & 24 h \\ OSR & \(\pm\)1.00 Wm\({}^{-2}\) & \(\pm\)0.10 Wm\({}^{-2}\) & 10–100 km per pixel & 3 h \\ OLR & \(\pm\)1.00 Wm\({}^{-2}\) & \(\pm\)0.10 Wm\({}^{-2}\) & 10–100 km per pixel & 3 h \\ EEI & \(\pm\)1.00 Wm\({}^{-2}\) & \(\pm\)0.10 Wm\({}^{-2}\) & – & 24 h \\ CO\({}_{2}\) & \(\pm\)1.0 ppm & \(\pm\)1.5 ppm & 1–5 km per pixel & 3 h \\ CH\({}_{4}\) & \(\pm\)10.0 ppb & \(\pm\)7.0 ppb & 1–5 km per pixel & 3 h \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Scientific requirements for satellite observations of ERB and GHG concentrations—Uvsq-Sat, Inspire-Sat7, Uvsq-Sat NG, and the future Terra-F constellation. Terra-F also focuses on determining Total Solar Irradiance (TSI) with good accuracy. A recent study dating back to 2021 highlighted that both satellite and oceanic data reveal a marked increase in the EEI [14]. The results demonstrate that independent observations from satellites and in situ measurements produced statistically similar decadal increases in the EEI from mid-2005 to mid-2019, amounting to approximately \(0.50\pm 0.47\,\mathrm{Wm}^{-2}\) per decade (5-95% confidence interval). This trend is primarily driven by an increase in absorbed solar radiation caused by reduced reflection from clouds and sea ice, as well as a decrease in OLR due to rising levels of GHGs. These changes together outweigh a positive trend in OLR associated with the overall increase in global mean temperatures. Using additional data from a Moderate-Resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), CloudSat, and reanalysis, [PERSON] et al. (2023) [15] also show once again that the rise in the EEI can be attributed to reduced cloud and sea ice reflection, leading to a significant increase in absorbed solar radiation [15]. Additionally, the increase in trace gases and water vapor contributes to a decrease in OLR. This demonstrates the importance of conducting these measurements to monitor the ERB components at various time scales. The ultimate goal is to ensure the seamless continuity of the ERB climate data records.