Blockchain aplicado em atualização de firmwaere de nanosatélites educacionais

Abstract

Space has increasingly attracted the attention of governments, large industries, and universities. One of the most popular strategies in recent years has been the adoption of nano-satellites to fulfill different missions, which can work alone or in constellations. Universities stand out among the agents launching nano-satellites, with more than 600 launches by 2022. Given the growth of entities that control space missions, it is necessary that new methods of communication between control and satellite be implemented to generate better use of communication windows, as well as more agility and security in data transmission. Our work proposed a consortium architecture between ground stations (GS) so that a GSaaS system, i.e. Ground Station As a Service, works with low cost, reliability and resource sharing. Initially, we simulated with matlab a nanosatellite mission in LEO orbit to obtain the parameters of average communication time, propagation loss, and at which angles the communication would be most affected by atmospheric phenomena. We then implemented business rules for communication between ground station and satellite using smart contract concepts. We set up a blockchain to provide the infrastructure for decentralization and created a webservice to provide an API for communication between the nanosatellite and the blockchain. We simulated the firmware upgrade process in our experiment. The results show that for a 301Kb firmware, fragmented into 32byte chunks, the nanosatellite took 19 minutes to perform all requests for the firmware fragments directly on the blockchain. This means that it would take at least 2 or 3 communication windows between the ground station and the satellite to perform all the activity. When we recorded in the server memory the results of the requests to the blockchain and then sent them one by one to the nanosatellite the time decreased to less than 6 minutes, less than the average communication window time in our simulation. Another difference is that we allow the consortium GSs to communicate in an "agnostic"manner with the satellites, meaning that firmware privacy will be preserved by the cryptography used and ownership of transactions in the blockchain. The system also allows institutions that own ground stations to share their resources and be remunerated for doing so.