The work started with the definition of the concept of operation of the EARS spacecraft and its preliminary architecture in order to identify the main requirements, the additional modules - and relevant technical characteristics - needed to make the EARS spacecraft suitable for re-entry to the Earth. As a starting point for the EARS design, we used a commercial small satellite that had already flown in space, the MP42 by Kongsberg Nanoavionics. Then we studied how to develop and integrate all the identified additional modules (propulsion, heat-shield, recovery parafoil and GNC for re-entry) needed to make the EARS spacecraft able to go back to the Earth with its products and results. Subsequently, we studied the technical specifications of the EARS spacecraft and traded off its mass, power and volume to integrate the additional modules and to optimise its performance. The major modifications needed to adapt the MP42 satellite to the EARS spacecraft requirements and mission objectives were also identified and studied.
A modular propulsion module – based on the use of two green chemical propellants - was designed to fulfil the requirements of the EARS spacecraft. The thruster of the propulsion system was constructed and successfully tested in a dedicated infrastructure against the EARS spacecraft requirements, suggesting also its reusability as a viable option.
An innovative heat-shield, based on inflatable technology, was preliminarily designed: it is made of a rigid nose and a three-layered inflatable system that protects the satellite during the re-entry. The materials needed for its construction were selected and extensively tested in relevant environment using the Plasmatron, a device able to reproduce the harsh environment experienced by the EARS satellite during the re-entry phase.
Novel guidance, navigation and control solutions to make the EARS able to re-entry the Earth atmosphere and to be recovered were studied. The needed sensors and actuators were identified and the critical algorithms and procedures were determined and developed. The algorithms were also successfully tested by means of a comprehensive test campaign that allowed to evaluate the landing accuracy for the EARS spacecraft. The results confirmed the feasibility of retrieving the EARS spacecraft by mid-air recovery using a helicopter.
Finally, EARS research and development activities were supported by addressing the future exploitation of the results, which was pursued through the analysis of the EARS business case, the generation of sustainable business model canvasses and the production of development roadmaps for each investigated technology. A detailed cost analysis, based on a gradual introduction of the reusability features in the platform design, demonstrated the achievement of significant savings compared to the traditional single-use spacecrafts.
