FSSCat
The FSSCat mission is an innovative concept consisting of two federated 6-Unit Cubesats, called ³Cat-5/A and ³Cat-5/B, in support of the Copernicus Land and Marine Environment services. These two CubeSats are the fifth generation of the ³Cat spacecraft family of the laboratory. They carry a dual microwave payload (a GNSS-Reflectometer and a L-band radiometer with interference detection/mitigation), and a multi-spectral optical payload to measure soil moisture, ice extent, and ice thickness, and to detect melting ponds over ice. It also includes a technology demonstrator of an Optical Inter-Satellite Link (OISL) and a proof-of-concept of a Federated Satellite System (FSS).
The FSSCat mission is the winner of the 2017 Copernicus Master ESA Small Satellite Challenge S^3 and Overall Winner.
As the NanoSat Lab is in charge of the development of the FMPL-2 and the FSSExp payloads, which are described below:
Flexible Microwave Payload - version 2 (FMPL-2)
The FMPL-2 payload aims at combining a Global Navigation Satellite System - Reflectometer (GNSS-R) and a L-band Radiometer in a single instrument, using Software Defined Radio (SDR). Using both measurements, this payload is able to produce scientific data to perform sea-ice detection and thickness monitoring, water ponds over ice, low resolution soil moisture. When the produced data is combined with the observables of the Hyperscout one, it is possible to achieve a high resolution soil moisture. The following figure represents the operation of the FMPL-2 in the ³Cat-5/A.
The FMPL-2 is integrated in 1-Unit+ and it is composed of three modules:
- The Radio Frequency (RF) Front-End module performs the signal conditioning and contains the calibration loads for the radiometer and amplifiers.
- The Interface Board module unifies the interfaces of the different modules to define a single communication and supply bus. In addition, it is the mechanical support for the GNSS receiver.
- The NanoSDR module contains a FPGA and Analog-to-Digital Converters (ADC) necessary to process the received signal, and produce the scientific data.
Federated Satellite System Experiment (FSSExp)
The FSSExp aims at demonstrating that the concept of Federated Satellite Systems (FSS), conceived by prof. Alessandro Golkar, is feasible in a CubeSat platform. In this context, a federation between satellites is a win-win collaboration to share unused resources, such as memory capacity or downlink opportunities. The experiment becomes thus a proof-of-concept of a federation between two 6-Unit CubeSats that share downlink opportunities. In particular, one of the satellites at certain moment has a downlink contact and publishes this resource as a service to the other satellite, that request it to exchange data to be downloaded. The following figure represents the operation of the payload.
The FSSExp payload is composed of two modules. The former is the software component of the experiment that contains all the algorithm and code to deploy a federation. This component is installed and executed in a host system integrated in both satellites. This hosting system, developed by Golbriak Space, provides memory and processing units necessary to execute the software. In addition, the communication between the satellites is established using the Radio Frequency (RF) Module, which is a Ultra High Frequency (UHF) communications module. This module is able to provide an Inter Satellite Link (ISL) wof 30% of packet error rate and 9.6 kbps of data rate in a maximum range of 1000 km. The following figure presents both RF ISL Modules used in the mission.
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