# INSPIRE-SAT 7, a Second CubeSat to Measure the Earth's Energy Budget and to Probe the Ionosphere
## 3 Description of the INSPIRE-SAT 7 Mission and Mission Operations
### The Space Segment
#### 3.2.1 The ERS Sensors  
To measure with accuracy the incoming solar radiation (TSI) and the Earth outgoing radiation (OSR and OLR), the INSPIRE-SAT 7 mission will use 12 ERS sensors (see their location in Figure 2). INSPIRE-SAT 7 ERS sensors are similar to those used onboard UVSQ-SAT. INSPIRE-SAT 7 has twelve broadband radiometers (180\({}^{\circ}\) field of view angle) that measure the Earth's radiation balance. The principle of this technology is explained in the UVSQ-SAT description manuscript [1]. To improve the results obtained with UVSQ-SAT, it is necessary to increase the sampling frequency (acquisitions every 10 s or better). Table 3 provides the technical expected performance of the ERS and temperature sensors to measure with high accuracy the incoming solar radiation and the Earth outgoing radiation. \begin{table}
\begin{tabular}{l l l} \hline
**Properties** & **Value** & **Comments** \\ \hline Orbit & Sun-synchronous orbit & Maximum altitude of 600 km, LTDN of 09:30 \\ Design life time & 2 years for LEO & 3 years desired \\ Launch date & Q1 2023 & Launch vehicle: Falcon 9 \\ \hline Size & 2 U & 11.5 cm (X) \(\times\) 11.5 cm (Y) \(\times\) 22.7 cm (Z) \\ Mass & 3.0 kg & Maximum with margins \\ \hline Solar cells & 20 & 3G30A solar cells provided by Azurspace \\ Batteries & 45 Wh @ 16 V & 4 Panasonic batteries (NCR18650B) with heaters \\ Power generated & 3.8 W & OAP in LEO \\ Power consumption & 3.2 W & Maximum orbit average with margins \\ \hline ADCS & 3-axis magnetometer & Measurements of the local Earth magnetic field \\  & 3-axis magnetorquer & 0.2 Am\({}^{2}\) magnetic dipole \\  & 6 SLCD-61N8 photodiodes & Coarse estimation of the Sun’s direction (\(\theta\)) \\ \hline CDHS and OBC & 400 MHz, 32-bit ARM9 & Processor \\  & 32 MB SDRAM & Synchronous Dynamic Random Access Memory \\  & 2 \(\times\) 2 GB SD-cards & Non-volatile data storage (SD card redundancy) \\  & 1 MB NOR flash & Code storage \\  & IEC, SPI, UARTs & UART is only used for debugging iOBC \\ \hline Data downlink & 1.2/9.6 kbps & UHF BPSK (437.410 MHz) communication \\ Data uplink & 9.6 kbps & VHF FSK (145.970 MHz) communication \\ Ground contact station & Less than 1 h per day & LATMOS station \\ Redundancy stations & LATMOS & Other stations: amateur radio partners \\ Downlink UVSQ-SAT data & 1.8 Mbyte per day & Maximum during a day \\ Uplink UVSQ-SAT data & 0.3 Mbyte per day & Maximum during a day \\ \hline Payload & 12 ERS & ERB measurements \\  & 4 TSIS & TSI measurements \\  & 10 UVS & UV SSI and ozone measurements \\  & 1 CUIIONOI payload & Ionospheric measurements \\  & 1 Li-Fi payload & Wireless communication system \\  & 1 SPINO payload & Functions for amateur radio community \\  & Audio transponder & FM live retransmission (amateur radio) \\  & 1 IMU & 3-axis accelerometer/gyroscope/compass \\ \hline Launch adapter & ISIPOD or Quad-pack & CubeSat deployer with a satellite mass up to 3 kg \\ \hline \end{tabular}
\end{table} 
Table 2: INSPIRE-SAT 7 CubeSat properties. Another area of improvement is linked to the sensitivity of the ERS sensors. As part of the INSPIRE-SAT 7 mission, the ERS sensors on the lateral faces have been enlarged compared to those used on UVSQ-SAT. Four ERS sensors are based on nano-thermopiles (active area of 10 mm \(\times\) 10 mm, responsivity of \(\sim\)1.5 \(\mu\)V per Wm\({}^{-2}\)) with carbon nanotubes (ERS\({}_{\rm{cn1}}\)). Four ERS sensors are based on nano-thermopiles (active area of 10 mm \(\times\) 10 mm, responsivity of \(\sim\)1.5 \(\mu\)V per Wm\({}^{-2}\)) with optical solar reflector (ERS\({}_{\rm{sr1}}\)). Two ERS sensors are based on nano-thermopiles (active area of 5 mm \(\times\) 5 mm, responsivity of \(\sim\)0.2 \(\mu\)V per Wm\({}^{-2}\)) with carbon nanotubes (ERS\({}_{\rm{cn2}}\)). Two ERS sensors are based on nano-thermopiles (active area of 5 mm \(\times\) 5 mm, responsivity of \(\sim\)0.2 \(\mu\)V per Wm\({}^{-2}\)) with optical solar reflector (ERS\({}_{\rm{sr2}}\)).