# INSPIRE-SAT 7, a Second CubeSat to Measure the Earth's Energy Budget and to Probe the Ionosphere
## 2 Scientific Objectives of the INSPIRE-SAT 7 Mission
### Ionosphere  
Another scientific objective of the INSPIRE-SAT 7 mission is based on ionospheric variability due to various solar and space weather effects and exploring different techniques of monitoring and modeling the ionosphere. Conditions of space weather could be unpredictable. Monitor the solar activity (UV observations) and probe the ionosphere status in near real time is fundamental to protect the satellites, but also navigations system and power grid system from breakdown. CubeSat can perform part of all space weather monitoring jobs. The number and configuration of the small satellite constellation is key into bringing the relevant space weather data to scientists. These observations can be carried out in the same CubeSat constellations dedicated to the measurements of ERB components and solar irradiance. \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Requirements** & **UVSQ-SAT** & & & \\ \hline Parameter & Absolute accuracy & Stability per year & Spatial resolution & Temporal resolution \\ \hline OSR & \(\pm 10.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 5.00\)\(\mathrm{Wm}^{-2}\) & \(2500\)\(\mathrm{km}\) & \(30\) days \\ OLR & \(\pm 10.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 1.00\)\(\mathrm{Wm}^{-2}\) & \(2500\)\(\mathrm{km}\) & \(30\) days \\ \hline
**Requirements** & **INSPIRE-SAT 7** & & & \\ \hline Parameter & Absolute accuracy & Stability per year & Spatial resolution & Temporal resolution \\ \hline OSR & \(\pm 5.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 1.00\)\(\mathrm{Wm}^{-2}\) & \(2500\)\(\mathrm{km}\) & \(10\) days with \(2\) CubeSats \\ OLR & \(\pm 5.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 1.00\)\(\mathrm{Wm}^{-2}\) & \(2500\)\(\mathrm{km}\) & \(10\) days with \(2\) CubeSats \\ \hline
**Requirements** & **Terra-F** & & & \\ \hline Parameter & Absolute accuracy & Stability per decade & Spatial resolution & Temporal resolution \\ \hline TSI & \(\pm 0.54\)\(\mathrm{Wm}^{-2}\) & \(\pm 0.14\)\(\mathrm{Wm}^{-2}\) & – & \(24\) h \\ OSR & \(\pm 1.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 0.10\)\(\mathrm{Wm}^{-2}\) & \(10\)–\(100\)\(\mathrm{km}\) & Diurnal cycle (\(3\) h) \\ OLR & \(\pm 1.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 0.10\)\(\mathrm{Wm}^{-2}\) & \(10\)–\(100\)\(\mathrm{km}\) & Diurnal cycle (\(3\) h) \\ EEI & \(\pm 1.00\)\(\mathrm{Wm}^{-2}\) & \(\pm 0.10\)\(\mathrm{Wm}^{-2}\) & – & – \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Scientific requirements (UVSQ-SAT, INSPIRE-SAT 7, and future Terra-F constellation). The Earth's atmosphere is made up of several layers, including the ionosphere which contains, as its name suggests, a lot of ions, but also electrons. When a large solar flare occurs, the amount of UV rays and X-rays entering the atmosphere increases. This radiation will tear electrons from molecules in the atmosphere, forming new ions in the ionosphere and making it denser. Once the solar eruption has passed, natural chemical recombination processes return the ionosphere to its normal state. Then, the characterization of the ionosphere is of renewed interest in the space weather problematic. Indeed, the ionospheric disturbances have a great influence on the quality of many telecommunications and observation services. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. The real-time knowledge of the ionosphere and its behavior become a major asset. The ionosphere is part of Earth's upper atmosphere. It extends from \(\sim\)50 km altitude up to about 1000 km above sea level. The ionosphere as a whole is electrically neutral.When the solar radiation strikes the atmosphere chemical constituents, electrically charged atoms and molecules are produced. The ionosphere is a dynamic and highly variable environment depending on solar activity and on the effects of geomagnetic storms. An excellent knowledge of the structure of the ionosphere represents an important scientific issue. The behavior of the ionosphere has to be monitored.