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Introduction Astrobiology is an interdisciplinary field covered by only a few CubeSat missions so far. Moreover, no CubeSat mission has ever mounted miniaturized technology for the purpose of searching for molecular evidences of life in space. AstroBio CubeSat (ABCS) is a 3U CubeSat selected by the European Space Agency (ESA) to be launched in spring 2022 with the Vega C maiden flight, as piggy back passenger of the ASI LARES2 mission. ABCS will host a payload assembly based on Lab-on-Chip (LoC) technology for biomarkers detection and will be deployed along a circular orbit with altitude of about 5900 km and inclination of 7°, therefore crossing the inner Van Allen belt where the radiation flux is close to its maximum. Due to the harsh environment, ABCS payload and subsystems will be likely exposed to damages and degradations of electronics and performances, thus the payload assembly and the operational architecture were designed to be as much dependable as possible. This approach should constitute the first step to implement a mature technology with the aim to check the stability of chemicals and biomolecules involved in space experiments. This work reports an overview of ABCS architecture and the approach chosen for its operational design. ABCS Architecture ABCS objective is to test in space an automatic in-situ multiparameter LoC [1], which exploits luminol injection and enzymatic bio-mimicking assays on a functionalized 3D wax-printed origami. Luminol will be transported by capillarity to reaction sites with immobilized biomolecules targets where the reactions will trigger chemiluminescence, detected by means of hydrogenated amorphous silicon (a-Si:H) photodiodes deposited on a borosilicate glass substrate and connected to a photocurrent readout board [2]. The described payload consists in an experiment board hosting the LoC and a support board containing peristaltic pumps for luminol injection, drivers for pumps, radiation field effect transistors (RADFETs) and pressure/temperature sensors. The LoC architecture allows to repeat the experiment up to six times. In addition to RADFETs, ABCS mounts an ancillary radiation dose sensor (ARDS), developed by Thales Alenia Space, with the aim to assess the radiation effects. The ARDS is able to measure different amounts of current, until its failure, depending on the dose acquired. To mitigate the effects of the expected very high flux of charged particles, an extra tungsten layer shielding was mounted on each side panel and all the main subsystems (experiment and support board, batteries and EPS board, on-board computer (OBC), telemetry, tracking and control board), were placed inside a 5 mm thick aluminium box. At the same time, to keep the temperature range (from 4°C to 20°C) and operative pressure (about 1 atm) required to allow the LoC capillarity effect and to prevent reagents degradation, the box was sealed and a thermal control system, composed by a multi-layer insulation and an active heather mounted inside the box, was implemented. ABCS Mission Design ABCS will be deployed in an approximately circular orbit at about 5900 km altitude and 70° of inclination, spending a significant amount of the orbital period within the inner Van Allen belt, very close to its radiation peak point. ABCS ground operations will be mainly performed from the School of Aerospace Engineering (SIA) Ground Station. Simulations show that SIA will have access to ABCS 4 times a day, with an average duration of about 65 minutes. For this reason, a network of radioamateurs and third part ground stations will be involved for supporting the collection of the telemetry and science data packages and possibly uplink commands. ABCS Operations The assumption we made is that ABCS should be able to perform the payload operations in a completely autonomous manner. As we know, radiation flux will most likely induce several errors on electronics and performances, causing potential mission failure due to the fact that payload operations may not start because the OBC fails to send the command to start the experiment. A possible way to reduce failure is to perform ABCS experiments where the proton flux is lower. Simulations shows that this happens when ABCS is at polar latitudes, namely outside the range [-60°; 60°]. For this reason, the payload operations, based on redundant checks and triggers, were implemented accordingly. The purpose is to automatically determine if ABCS is at a latitude useful to perform the experiments and verifying this condition by means of multiple triggers, time or position based. Each trigger is used for scheduling purposes only if the ones with higher priority are unreliable. If all the triggers are not reliable, payload operations are forced to begin, as it is better to perform eventually degraded payload operations rather than performing no payload operations at all. Conclusions ABCS is required to operate in an extremely harsh environment where radiation fluxes are likely to degrade the electronic devices. Operations should be scheduled in order to reduce the time needed to perform all the experiments. The chosen approach will lead ABCS to complete the payload operations in three orbital periods, reducing the total ionizing dose absorbed and guaranteeing the higher system reliability. Acknowledgments ABCS AstroBio-CubeSat is supported by ASI - Italian Space Agency ASI/INAF Agreement n. 2019-30-HH.0. References [1] Iannascoli, L. et al. 2020, "Astrobio cubesat: Enabling technologies for astrobiology research in space", Proceedings of the International Astronautical Congress, IAC. [2] Mirasoli M, et al. 2014. Multiwell cartridge with integrated array of amorphous silicon photosensors for chemiluminescence detection: development, characterization and comparison with cooled-CCD luminograph. Anal Bioanal Chem. Sep;406(23):5645-56.

IntroductionAstroBio CubeSat (ABCS) is an Italian Space Agency (ASI) 3U CubeSat (100x100x340 mm) selected by European Space Agency (ESA) to be launched with the Vega C qualification maiden flight, as piggy back of the ASI LARES2 main satellite, by the end of 2020. ABCS will be deployed in an approximately circular orbit, with about 5900 km altitude and 70° of inclination. It implies that ABCS will spend a significant part of the orbital period within the internal Van Allen belt, close to its maximum. The radiation environment is characterized by a very high flux of charged particles, which have a significant effect on electronic components in terms of permanent damages due to accumulated dose effects and single events. Considering the extremely harsh space conditions, the estimated mission lifetime useful to perform the payload experiments should be defined in 3 months.ABCS Project is funded and managed by ASI in cooperation with INAF-Astrophysical Observatory of Arcetri, that will coordinate the scientific and engineering team. Partners of the projects are the School of Aerospace Engineering of Sapienza University of Rome, the University of Bologna, the University of Torino, and Kayser Italia.ABCS PayloadABCS will host a mini laboratory payload based on an innovative lab-on chip technology suitable for research in astrobiology. The objective is to test in space environments an automatic laboratory able to provide a highly integrated in-situ multiparameter platform that uses immunoassay tests exploiting chemiluminescence detection by means of on-chip a-Si:H photodiodes. The experiment will consist in a set of lateral flow immunoassays (LFIA) on nitrocellulose support where target biomolecules are immobilized in specific test areas. Reagents are deposited in a non-permanent fashion and in a dry form in the initial part (starting area) of the microfluidic path. When the reagents-delivery-system provides a volume of liquid reagent to the starting pad, capillary forces will guide the reagents through the LFIA microfluidic pathway. During the flow, liquid reagents will solubilize and transport along the path the deposited reagents, triggering specific reactions and allowing the chemiluminescence detection by the photodiodes.ABCS also mounts an ancillary radiation dose payload, to investigate the degradation of of electronic components exposed to the space environment. The device has twin components protected by established radiation screens, kindly provided by Thales Alenia Space Italia and by CESI, so that the degradation can be assessed on the basis of the difference between the observed currents.ABCS architecture and payload are based on the strong heritage gained by the research team with the ground validation of the PLEIADES (Planetary Life Explorer with Integrated Analytical Detection and Embedded Sensors) instrument, an R&D ASI project recently concluded.Enviromental challengesThe main challenges of the project are to mitigate the effects of the expected very high flux of charged particles, keeping the correct temperature (4°C/25°C) and pressure (about 1 atm) range for the payload to prevent reagents degradation. This invoked a series of technological solution to protect the payload. The pressurized environment is ensured by an inner aluminium box, hosting both the experiment and the main subsystems (batteries, on-board data handling, telemetry, tracking and control) hermetically sealed and providing shielding from radiation and charged particles. A thermal control system, including a passive control multi-layer insulation and an active heather mounted inside the pressurized box, maintain the temperature in the desired range.ConclusionABCS mission aims at evaluating the overall system functionality (delivery of reagents, mixing of chemicals, LoC characterization, detection of emitted photons, readout noise, etc.) such as the chemicals and biomolecules stability (reagents and antibodies employed in the experiment) in the extremely harsh environment.The in-orbit validation of the proposed technology would represent a significant breakthrough for autonomous execution of bio-analytical experiments in space with potential application in search for signs of life in planetary exploration missions, space biolabs without human support, health monitoring in manned missions.