# 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
### Inspire-SAT 7 Mission Concept of Operations and Calibration and Validation (Cal/Val)
A first pre-flight absolute calibration of each ERS sensor will be done with the LATMOS BX-500 blackbody, which offers a wide field of view for the calibration of the sensors. The blackbody (diameter of 57 mm, emissivity of 0.95, minimum distance with the sensors of around 40 mm) will be operated at several set-point increments of 5 K from 323 K to 343 K. The pre-flight absolute calibration of each ERS sensor will also be carried out with the BB 3200 pg (as pyrolytic-graphite) blackbody of Physikalisch-Technische Bundesanstalt (Germany) as primary standard [19; 20]. The BB 3200 pg blackbody (opening area of 111.4 mm\({}^{2}\), minimum distance with the sensors of around 700 mm) will be operated at several temperatures between 2800 K and 3150 K. Finally, the INSPIRE-SAT 7 CubeSat will be integrated into the LATMOS/OVSQ INTRA Solar Tracker (0.038\({}^{\circ}\) resolution) to calibrate the ERS sensors in visible bands toward the  
Figure 6: INSPIRE-SAT 7 uplink configuration. Sun. Ground-based pyranometers (Kimo SAM30 (400 to 1100 nm, unidirectional, 1 to 1300 Wm\({}^{-2}\)) and Kipp & Zonen SMP6-V (270 to 3000 nm, field of view of 180\({}^{\circ}\), 0 to 1600 Wm\({}^{-2}\) with an uncertainty of \(\pm\) 20 Wm\({}^{-2}\))) will also be integrated on the solar tracker to provide an independent measurement of the solar flux that could be compared to that measured by the ERS sensors. From these different tests led by LATMOS, a pre-flight absolute uncertainty close to \(\pm\)5 Wm\({}^{-2}\) (1 \(\sigma\)) is expected for OSR and OLR. A pre-flight absolute calibration of the TSIS sensors will be done with a LATMOS test bench that simulates an artificial Sun (Newton telescope (focal of 1410 mm, diameter of 20 cm, image field of 0.5\({}^{\circ}\)), Xenon arc lamp (model 6269) of 1000 W where the Xenon lines dominate between 750 and 1000 nm, but the spectrum is almost featureless through the ultraviolet and visible). A pre-flight absolute calibration will also be done with the INTRA Solar Tracker. From these different tests led by LATMOS, a pre-flight absolute uncertainty close to few % is expected for TSI. A pre-flight absolute calibration of the UVS sensors will be done with a LATMOS test bench (Stellarnet SL3 deuterium light source (UV for the 190-450 nm range, power output of 15 Wm\({}^{-2}\)), chopper, scanning monochromator Optometrics SDMC1-01, Keithley 2450 sourcemeter (I-ranges of 10 nA to 1 A, 0.012% of accuracy)). Finally, the UV-VIS BIRA-IASB facilities will be used for the calibration of the UVS sensors. This facility delivers a monochromatic and tunable light beam produced by a combination of a double monochromator, and different lamps (UV arc lamp, solar simulator, tungsten lamp). The output monochromatic light can be collimated or injected in a large (\(\sim\)30 cm) integrating sphere for spectral response characterization or flat field measurements. From these different tests led by LATMOS and BIRA-IASB, a pre-flight absolute uncertainty close to few % is expected for UV SSI. No direct on-orbit calibration is possible because the CubeSat is too small to integrate in-flight calibration sources. For ERS sensors, we use carbon nanotubes that are not subject to aging in orbit. The aging of these sensors is considered as weak. However, payload electronics can undergo aging in orbit. Thus, standard (etalon) currents have been integrated into the INSPIRE-SAT 7 payload printed circuit board to check the stability of the sensors electronic (ERS, TSIS, UVS). In the future, we wish to use sources of gallium (melting point of 302.91 K) to monitor the aging of ERS sensors for example.