Verification of a CubeSat via Hardware-in-the-loop Simulation

This paper describes the Hardware-In-the-Loop (HIL) simulation methodology used for the verification of functional requirements of e-st@r-I CubeSat. The satellite’s behavior has been investigated via HIL simulation, and the results obtained are consistent with the expected values in any operative conditions. It is proven that HIL simulation is a valuable means for supporting the verification process of small satellites and may help reduce time and cost of the development phase and increase mission reliability

The Crip, The Fat and The Ugly in an Age of Austerity: Resistance, Reclamation and Affirmation

Welcome to this special forum, The Crip, The Fat and The Ugly in an Age of Austerity: Resistance, Reclamation and Affirmation. Our original desire in putting out this call was to critically explore the processes and politics of austerity upon diverse and marginalized embodiments in neoliberal and advanced capitalist times. Global austerity has a far reach, often into, around, behind, beyond and alongside the body. Global austerity routinely categorizes body-minds[i] in terms of productivity, value, cost, ability and aesthetics. Body-minds are positioned vis-a-vis global austerity as a site for social order, economic possibility, progression, and big business. Whereas “[a]n able body is the body of a citizen; deformed deafened, amputated, obese, female, perverse, crippled, maimed and blinded bodies do not make up the body politic” (Davis, 1995, pp. 71–72). In devising this forum, we yearned for space to contemplate the aesthetics, experiences and the reification of body-minds - how capitalism makes sense of and shapes body-minds; the ways in which austerity both marks and produces bodies and selves, and the means through which these are further shaped by disability, race, class, gender, age, size, sexuality, and nation. Although we explore aspects of these in our own work (Liddiard, 2018; Slater, 2015), we wanted to create a space to connect with others and think about diverse and marginalized embodiments in austere times. In this introduction, we story the process through which we put the issue together, from our original decision making and putting out the call, to supporting authors to revise their contributions. We do so because we feel it’s a fitting way to speak to the inclusions and exclusions made in this forum. At the same time, we feel it offers a broader commentary as to the “state” of global disability studies today

Three scenarios fro valuable planetary science missions on Mars: next generation of CubeSats to support space exploration

Planetary science originally tended to make use of “flagship” missions characterized by big satellites and expensive resources. In the near future this traditional satellite paradigm could dramatically change with the introduction of very small satellites. This shift towards smaller, less expensive devices mirrors the paradigm shift that happened in the computer industry with the miniaturization of electronics, as focus has moved from massive machines to personal computer up to smart phones. The ultimate expression of spacecraft miniaturization is today represented by CubeSats, but while over a hundred CubeSats have been launched into Earth orbit, space-based research beyond LEO struggles to find practical application. CubeSat small size poses hard challenges for independent planetary exploration, nevertheless they remain highly attractive due to the reduced development time and cost coming from platform modularity and standardization, availability of COTS parts, reduced launch cost. Constellations of CubeSats, collaborative networks, fractionated or federated systems are becoming popular concepts as they can offer spatially distributed measurements and the opportunity to be used as disposable sensors with a flexibility not achievable by single-satellite platforms. We have worked towards advancing the state of the art in CubeSat missions design and implementation by defining the range of science capabilities for CubeSats beyond LEO, and by enhancing the top technological challenges to support science objectives (e.g. propulsion, communications, radiation environment protection). Planet Mars was chosen as target destination to the purpose of this work, by selecting a set of scientific objectives for CubeSats to serve astrobiology goals and future human exploration. Missions to accomplish orbital and atmospheric measurement, in situ analyses related to biosignatures detection and environmental characterization have been explored. The opportunity to rely on already existing space assets in the proximity of Mars, or on a “mothership” for data relay or orbit insertion, has been considered in this context. A tradespace exploration led to the definition of three classes of mission architectures, respectively based on surface penetrators, atmosphere scouts and orbiting fleet. Each architecture has been assessed in the perspective of science return against a set of leading indicators that draw out cost, utility, complexity, technology readiness among others. For each class a mission concept has been created, providing a basis to elicit the definition of top-level requirements and to assess the value of science return in the context of complex mission scenarios

Analysis of the communication anomaly during E-ST@R-2 mission operations

To increase probability of success of future nanosatellite missions, data gathered from orbit operations are of paramount importance, especially if anomalies are observed. E-st@r-2 Cubesat was launched on April 2016 in the framework of the Fly Your Satellite! programme of the European Space Agency. Few anomalies were detected during operation, which compromised the mission either temporary or permanently. This paper describes the investigation of a major anomaly that seriously affected mission operations, i.e. low Signal-to-Noise ratio of downlink communication. In particular, no signal could be received at the main control station. Only ground stations with high gain antennas and/or proper system set up could receive and decode e-st@r-2 packets, whereas standard radio amateur station failed. For this reason, both space and ground segments were identified to be part of the problem. The analysis performed to cope with the issue covered several phases of mission lifecycle, from design to assembly, integration and test, until operations. The investigation on the anomaly has been done by means of analysis and test activity. A loss of 12 to 15 dB was estimated with respect to the link budget. A fault tree analysis was developed to identify the failure or combination of failures that resulted in the mishap. A failure modes and effects analysis of communication system was carried out, as this subsystem was identified as the major contributor to the anomaly. In parallel, testing activity was performed on the engineering model of cubesat. A thorough test campaign was planned and executed at equipment, subsystem and system level. Test results on the engineering model were compared with orbit data and results of qualification campaign on the flight unit. The investigation showed that possible causes of the anomaly could be either incomplete deployment of the antenna, or incorrect antenna connection, or loss of power in the transceiver, or a combination of these causes amplified by the tumbling motion of the CubeSat. Taking into account the extensive test campaign executed on the flight unit during development, the failures of antenna deployment and of high-power amplifier circuit are extremely unrealistic. Instead, a potential defect was detected on the coaxial cable connection to the antenna, which might have caused the final mishap under investigation. The analysis also showed that an effective ground segment helps mitigating the impact of the anomaly, thus increasing mission success to a great extent, and it is worth investing more on this mission element

Feasibility Study of a Technological Demonstrator of Reduced Size for Sub-Orbital Flight

The Unmanned Space Vehicles program (USV), managed by the Italian Aerospace Research Centre (CIRA), is a science and technology knowledge development program, oriented towards future generations of Reusable Launch Vehicles, capable of performing frequent, and affordable launches into space. The USV program has been defined based on the belief that future space access and re-entry will be guaranteed by aviation-like vehicles. The USV program therefore aims at the development of innovative technologies for future space vehicles. The program pursues an approach characterized by increasing mission complexity: three Flying Test Beds (FTBs) will be designed and built to perform four experimental flight tests. The planned missions are: Dropped Transonic Flight Test (DTFT), Sub-orbital Re-entry Test (SRT), Hypersonic Flight Test (HFT) and Orbital Re-entry Test (ORT). As these FTBs are thought as vehicles of considerable size, about 7.5 meters long, the study and development of smaller technological demonstrators, conceived to lead to the realization of bigger ones, appear attractive thanks to their high benefit-to-cost ratio. The aerospace system research group at Politecnico di Torino has been working at the design of small and affordable technological demonstrators for many years now and different configurations have been developed. In collaboration with CIRA, Università di Napoli “Federico II” and Università di Roma “La Sapienza”, our research group has carried out the feasibility study of a small vehicle oriented towards the execution of the SRT mission. The vehicle has been called “Mini-FTB” and its mission “Mini-SRT“. The CIRA demonstrator for the original SRT mission (FTB_2) is powered by one solid rocket engine. It will be dropped from a stratospheric balloon at an altitude of about 35 km. After that, the rocket is ignited to accelerate the vehicle along a sub-orbital trajectory up to a maximum altitude of about 120 km. Then the vehicle starts the re-entry phase along a trajectory designed to maximize heat fluxes, that remain higher than 650 kW/sqm for about 15 seconds, achieving the maximum value at about 25 km. A parachute system allows the recovery of the vehicle. Main target of the Mini-SRT mission is to improve technological and scientific knowledge useful to reduce risks connected to the SRT mission by means of a low cost and thus low risk system. The paper starts with an overview of the design process and the proceeds with the description of requirements, mission profile and system configuration. The paper then focuses on subsystems sizing and investigate the aerothermodynamics issue. Eventually preliminary cost estimations are show and main conclusions are drawn. Results are encouraging as the feasibility study has shown that the Mini-FTB can be built and tested

DESIGN AND ANALYSIS OF AN INNOVATIVE CUBESAT THERMAL CONTROL SYSTEM FOR BIOLOGICAL EXPERIMENT IN LUNAR ENVIRONMENT

After about 50 years since the Apollo missions, Space Agencies are planning new manned missions beyond LEO, aiming to full functional Lunar and Martian outposts. Leaving the protection of Earth’s magnetic field, human body will be exposed by a huge amount of harmful radiations coming from both solar wind and cosmic rays, which represent a risk for the astronauts. In order to prepare for future manned exploration missions, many biological experiments have been conducted inside and outside the International Space Station (ISS). From these experiments, engineers and scientists gained knowledge about biological degradation after a long period of exposure to space radiations. Similar experiments were also carried out in small free-flyers. For example, the O/OREOS mission is built with a 3U CubeSat that is evaluating how microorganisms can survive and can adapt to the harsh orbit environment. Small platforms, such as CubeSats, are gaining interest for many applications including science experiments. Biological payloads require very stable environmental conditions, implying that environment requirements are very stringent and that existing passive thermal control systems may not be sufficient to support these class of experiments. The goal of this paper is to describe and discuss the design of an active environmental control system suitable for supporting biological payloads hosted onboard nanosatellites. In particular, we focused the attention on the case of a payload constituted by a bacterial culture that needs oxygen supply for growing up. The rate of growth and vitality are measured through bacteria metabolic parameters. The reference mission is built with a 6U CubeSat in Lunar Polar Orbit, with the main scientific objective of measuring the effect of the lunar radiation environment on a culture of “Bacterium Deinococcus Radiodurans”. This kind of bacteria exhibits significant resistance to ionising radiation and the survival temperature range is 30°C ± 10°C. The thermal control system (TCS) is constituted by Stirling cryocooler, Peltier cells and heaters. The aforementioned pieces of equipment operate on the oxygen tank and test chamber in order to control temperature of the oxygen necessary for the growth of the bacteria. To verify the temperature requirements, two kinds of analysis are performed: radiative analysis, to have information about the heat fluxes from space environment; and lastly, a thermo-fluid dynamics analysis, to gather data about temperature in the test chamber. As result, it is possible to confirm that, with the chosen TCS, the temperature requirement is verified during the mission

ASSESSMENT OF NEW TECHNOLOGIES IN A MULTI-DISCIPLINARY DESIGN ANALYSIS AND OPTIMIZATION ENVIRONMENT INCLUDING RAMS AND COST DISCIPLINES

The aim of the present paper is to assess the effect of new technologies on the whole aircraft product including its costs, reliability and maintainability characteristics. Several studies have been conducted dealing with the preliminary evaluation of Reliability, Availability, Maintainability and Safety (RAMS) of conventional aircraft. They provide a very effective method to preliminary estimate RAMS characteristics but their employment is not completely suitable for the analysis of unconventional configurations adopting new technologies. This paper aims at evaluating how the aircraft costs and RAMS characteristics are affected by new structures material, natural laminar flow wing technology and unconventional actuator system (electro-hydrostatic actuators), hence an update of the state of the art models is needed. This evaluation is performed by means of a setup and execution of a Multidisciplinary Design Analysis and Optimization (MDAO) workflow. The MDAO environment includes the aircraft conceptual design, aircraft performance, structure design, engine design, on-board systems design, RAMS and maintenance cost modules. The RAMS module is used to obtain the failure rates and maintenance effort (in terms of maintenance man hour per flight hour) at subsystem level. The cost module is based on a new maintenance cost model able to estimate the operating cost of the different aircraft variants. The selected new technologies are applied to a regional jet developed within the framework of AGILE research project. For each technology, a different variant of this aircraft is analyzed. Results show that some important saves are reached both in terms of maintenance and fuel cost when new technologies are applied