# UVsq-Sat NG, a New CubeSat Pathfinder for Monitoring Earth Outgoing Energy and Greenhouse Gases
## 3 Description of the Uvsq-Sat NG Space-Based Mission
### Description of the Uvsq-Sat NG Satellite and Its Payloads  
Uvsq-Sat NG (Figure 1) is a three-axis stabilized satellite of the Six-Unit class CubeSat, with an overall size of \(111.3\times 36.6\times 38.8\) cm (unstowed configuration) and a maximum mass budget constraint of 10 kg. The projected mission duration is at least 2 years, which includes the commissioning phase. During this period, the satellite will collect crucial data of the ERB and GHGs. Uvsq-Sat NG is a complex system composed of various subsystems. Many subsystems of Uvsq-Sat NG have already been used in Uvsq-Sat and InspireSat7. They are described in detail in the articles dedicated to these satellites [8; 9]. The Uvsq-Sat NG Command and Data Handling Subsystem (C&DHS) plays a pivotal role in ensuring the spacecraft's successful operation and management by serving various important objectives. The main component of the C&DHS Subsystem is the CubeSat On-Board Computer (OBC), which executes ground commands for various functions; manages data processing, storage, and transmission; collects telemetry data for monitoring; enables autonomous operations and fault management; handles scheduling and power distribution; implements security measures; and manages software updates and validation. The Uvsq-Sat NG Electrical Power Subsystem (EPS) is tasked with generating, storing, regulating, and distributing electrical power necessary for operating the various subsystems and instruments onboard. It ensures a consistent and dependable power supply throughout the satellite's mission in space. The essential components and functions of this subsystem encompass an EPS board stack with its eight batteries, the deployable solar panels with Azur Space cells, the power distribution unit, regulation, management, and thermal control. The Uvsq-Sat NG communication subsystem is tasked with establishing and maintaining communication links between the satellite and ground stations. Its primary goal is to enable the smooth transmission of data, commands, and telemetry information to and from the satellite. The key components of this subsystem include the TRXVU communication device (UHF/VHF band), the UHF/VHF antennas, the TXS high-data-rate S-band transmitter, and the S-band patch antenna. The S-band downlink, with the platform oriented towards Nadir, falls within the frequency allocation of 2200 to 2290 MHz. The Isspace VHF Receiver (RX) operates in the commercial frequency range of 148 to 150.5 MHz, and for amateur frequency coordination, it operates within the frequency range of 145.8 to 146.0 MHz. On the other hand, the Isispace VHF Transmitter (TX) covers the commercial frequency range of 400.15 to 402.0 MHz and, for amateur usage, it spans the range of 435.0 to 438.0 MHz. An audio transponder will also be used with the amateur radio community. Uvsq-Sat NG carries multiple payloads, including the ERSs that have been previously used in our earlier missions (Uvsq-Sat and Inspire-Sat7). The detailed characteristics of these sensors dedicated to ERB observations are provided in [8; 9]. A miniaturized spectrometer dedicated to GHG observation is also onboard. This NIR Spectrometer fits within a volume of less than 1 unit (\(10\times 10\times 10\) cm) and has a 15 mm aperture. It is composed of a 300 groves/mm grating and an Indium Gallium Arsenide (InGaAs) linear image sensor equipped with a Peltier thermoelectric cooler, offering integration times ranging from 0.5 to 4 s. Improved results (GHG observations) can be achieved if the Uvsq-Sat NG NIR Spectrometer temperature is maintained below \(-5\) degC. Finally, a high-definition camera is used to ensure the geolocation of observations and to achieve secondary scientific objectives. With a frame rate of 12 frames per second, the imaging CMOS sensor enables a complete capture within a total time of 84 milliseconds. Table 2 provides the key features of the different payloads. As for Table 3, it provides the general characteristics of the satellite that ensure the mission's performance.