A Test Platform to Assess the Impact of Miniaturized Propulsion Systems

Miniaturized propulsion systems can enable many future CubeSats missions. The advancement of the Technology Readiness Level of this technology passes through the integration in a CubeSat platform and the assessment of the impact and the interactions of the propulsion systems on the actual CubeSat technology and vice versa. The request of power, the thermal environmental, and the electromagnetic emissions generated inside the platform require careful analyses. This paper presents the upgraded design and the validation of a CubeSat test platform (CTP) that can interface a wide range of new miniaturized propulsion systems and gather unprecedented information for these analyses, which can be fused with the commonly used ground support equipment. The CTP features are reported, and the main achievements of the tests are shown, demonstrating the effective capabilities of the platform and how it allows for the investigation of the mutual interactions at system level between propulsion systems and the CubeSat technology

Orthogonal-Array based Design Methodology for Complex, Coupled Space Systems

The process of designing a complex system, formed by many elements and sub-elements interacting between each other, is usually completed at a system level and in the preliminary phases in two major steps: design-space exploration and optimization. In a classical approach, especially in a company environment, the two steps are usually performed together, by experts of the field inferring on major phenomena, making assumptions and doing some trial-and-error runs on the available mathematical models. To support designers and decision makers during the design phases of this kind of complex systems, and to enable early discovery of emergent behaviours arising from interactions between the various elements being designed, the authors implemented a parametric methodology for the design-space exploration and optimization. The parametric technique is based on the utilization of a particular type of matrix design of experiments, the orthogonal arrays. Through successive design iterations with orthogonal arrays, the optimal solution is reached with a reduced effort if compared to more computationally-intense techniques, providing sensitivity and robustness information. The paper describes the design methodology in detail providing an application example that is the design of a human mission to support a lunar base

ENTRY, DESCENT AND IMPACT SYSTEM DESIGN AND ANALYSIS OF A SMALL PLATFORM IN MARTIAN ENVIRONMENT

Thanks to the latest Mars missions, planetary exploration has made enormous strides over the past ten years increasing the interest of the scientific community and beyond. These missions must fulfil many complex operations which are of paramount importance to mission success. Among these, a special mention goes to the Entry, Descent and Landing (EDL) functions which require a dedicated system to overcome all the obstacles of these critical phases. The goal of this study is to describe in detail the design methodology for EDL system during the preliminary phase of the design. The design is supported by a simulation tool integrating the entry trajectory algorithm. The trajectory data computed are used to size the EDL system and strategy in order to have a low aerodynamic acceleration, low dynamic pressure and low convective heat flux incoming to the spacecraft. The reference mission has the goal to find bioevidence and biohazards on Martian subsurface in order to prepare future manned missions. The mission is based on Space Penetrator Systems (SPS) that can descend on Mars surface following a ballistic fall and penetrate the ground after the impact with the surface (around 50 and 300 cm depth). The SPS contains all the instrumentation required to sample and make the required analyses. As results, an Entry Descent and Impact (EDI) system based on inflatable structure is designed, respecting the low-cost and low-mass constraints. For this mission, a solution, like the one of Finnish Meteorological Institute in the Mars Met-Net mission, is chosen, using an inflatable Thermal Protection System (TPS) called Inflatable Braking Unit (IBU) and an additional inflatable decelerator. Consequently, there are three configurations during the EDI phases: at an altitude of 125 km, the IBU is inflated at speed 5.5 km/s; at an altitude of 16 km, the IBU is jettisoned and an Additional Inflatable Braking Unit (AIBU) is inflated; at last, at about 13 km, the SPS is ejected from AIBU and it impacts on the Martian surface. In this paper, the results obtained by the application of this design methodology are presented and, the obtained system and descent strategy satisfy the requirements of the mission

Software Reference Architecture for CubeSats – A Direct Approach

Ever since the first CubeSat mission was launched, the concept and complexity of CubeSat missions has evolved at a pace that current operational system/doctrine cannot match. In an increasingly dynamic space economy, where small businesses have become the norm, innovative solutions that abstract away complexity and increase autonomy are fundamental to reduce operational costs. It is within this frame that the current study is presented. To address the need for a standardized software architecture of NewSpace companies, we first assess the European small satellite market needs through a survey with key players in the space sector. From this survey, we derive the high-level requirements, functionalities, and interfaces of a software architecture for CubeSats, the preferred platform due to its lower cost when compared with traditional platforms. Finally, we report the implementation results of a set of these components and show how they reflect design drivers

Development and Validation of on-board systems control laws

Purpose - The purpose of this paper is to describe the tool and procedure developed in order to design the control laws of several UAV (Unmanned Aerial Vehicle) sub-systems. The authors designed and developed the logics governing: landing gear, nose wheel steering, wheel braking, and fuel system. Design/methodology/approach - This procedure is based on a general purpose, object-oriented, simulation tool. The development method used is based on three-steps. The main structure of the control laws is defined through flow charts; then the logics are ported to ANSI-C programming language; finally the code is implemented inside the status model. The status model is a Matlab-Simulink model, which uses an embedded Matlab-function to model the FCC (Flight Control Computer). The core block is linked with the components, but cannot access their internal model. Interfaces between FCCs and system components in the model reflect real system ones. Findings - The user verifies systems' reactions in real time, through the status model. Using block-oriented approach, development of the control laws and integration of several systems is faster. Practical implications - The tool aims to test and validate the control laws dynamically, helping specialists to find out odd logics or undesired responses, during the pre-design. Originality/value - The development team can test and verify the control laws in various failure scenarios. This tool allows more reliable and effective logics to be produced, which can be directly used on the system

Lessons learned of a systematic approach for the e-st@r-II CubeSat environmental test campaign

CubeSat-standard satellites have become more and more popular during last years. Education objectives, mainly pursued in the first CubeSat projects, have given way to the design of missions with other-than-education objectives, like Earth observation and technology demonstration. These new objectives require the development of appropriate technology. Moreover, is necessary to ensure a certain level of reliability, because education-driven mission often failed. In 2013 the ESA Education Office launched the Fly Your Satellite! Initiative devoted to provide six university teams with the support of ESA specialists for the verification phase of their CubeSats. Within this framework, the CubeSat Team at Politecnico di Torino developed the e-st@r-II CubeSat. E-st@r-II is a 1U satellite with educational and technology demonstration objectives: to give hands-on experience to university students; to demonstrate the capability of autonomous attitude determination and control, through the design, development and test in orbit of an A-ADCS; and to test in orbit COTS technology and in-house developed hardware and software (as UHF communication subsystem and software for on-board and data handling subsystem). The paper describes the application of a systematic approach to the definition, planning and execution of environmental test campaign of e- st@r-II CubeSat and the gathered lessons learned. The approach is based on procedures designed and assessed for the vibrations and thermal-vacuum cycling tests of a CubeSat accordingly to ECSS rules and with the support of ESA specialists. Concretely, ECSS application, tailored to fit a CubeSat project, allowed to define a test plan oriented to reduce verification duration and cost, which lead to a lean verification execution. Moreover, the interaction with ESA thermal and mechanical experts represented a valuable aid to increase the Team know-how and to improve and optimise the verification plan and its execution. The planning encompasses the analysis of the requirements to be verified that have been gathered in such a way that the tests duration has been reduced. The required tests, like thermal- vacuum cycling and bake-out tests, have been combined in order to speed-up the verification campaign. The tests outputs shown that the satellite is able to withstand launch and space environment. Furthermore, satellite expected functionalities have been tested and verified when the CubeSat is subjected to space environment, in terms of temperature and vacuum conditions. In conclusion, it has been successfully demonstrated that the proposed approach allows executing a lean CubeSat verification campaign against environmental requirements following a systematic approach based on ECSS