Qualification Model Research Articles

Results of the qualification test campaign of a Pulsed Plasma Thruster for Cubesat Propulsion (PPTCUP)

Pulsed Plasma Thruster for Cubesat Propulsion (PPTCUP) is an ablative pulsed plasma thruster designed with the aim of providing translational and orbital control to Cubesat platforms. The qualification model presented in this paper has been developed by Mars Space Ltd, Clyde Space Ltd and the University of Southampton to produce a versatile “stand-alone” module that can be bolted on the Cubesat structure, allowing the orbital control along the X or Y-axis of the satellite. An extensive and complete test campaign to qualify the unit for space flight, which includes electromagnetic compatibility (EMC) characterization, thermal cycling and mechanical tests, has been performed according to the NASA GEVS procedures. PPTCUP is characterized by an averaged specific impulse of 655±58s and a deliverable total impulse of 48.2±4.2Ns. Finally, it has been found that the unit is compliant with the EMC requirements and can successfully withstand the thermal and mechanical loads typical of a Cubesat space mission.

Development of a space-borne spectrometer to monitor atmospheric ozone.

A new compact satellite spectrometer dedicated to monitoring terrestrial atmospheric ozone (ozonometer) is in preparation for the Russian Geophysics Program. Four instruments at four satellites (Ionosphere) are intended to monitor the total ozone content by measuring spectra of scattered solar radiation in nadir. The spectrometer is based on the Rowland scheme with a concave holographic diffraction grating. It covers the near UV and visible range of the spectrum, 300-500nm, with a spectral resolution of ∼0.3 nm. At present, a qualification model has been manufactured and tested. We introduce the description of the instrument and the results of laboratory and ground-based atmospheric calibrations. The ozone amount retrieved from atmospheric measurements using the differential optical absorption spectroscopy (DOAS) method is in good agreement with that measured by the collocated Brewer spectrophotometer and ozone monitoring instrument on board the Aura satellite.

FIRST DETECTION OF [C I] 3 P 1 – 3 P 0 EMISSION FROM A PROTOPLANETARY DISK

We performed single point [C I] $^3$P$_1$-$^3$P$_0$ and CO J=4-3 observations toward three T Tauri stars, DM Tau, LkCa 15, and TW Hya, using the Atacama Large Millimeter/submillimeter Array (ALMA) Band 8 qualification model receiver installed on the Atacama Submillimeter Telescope Experiment (ASTE). Two protostars in the Taurus L1551 region, L1551 IRS 5 and HL Tau, were also observed. We successfully detected [C I] emission from the protoplanetary disk around DM Tau as well as the protostellar targets. The spectral profile of the [C I] emission from the protoplanetary disk is marginally single-peaked, suggesting that atomic carbon (C) extends toward the outermost disk. The detected [C I] emission is optically thin and the column densities of C are estimated to be <~10$^{16}$ cm$^{-2}$ and ~10$^{17}$ cm$^{-2}$ for the T Tauri star targets and the protostars, respectively. We found a clear difference in the total mass ratio of C to dust, $M$(C)/$M$(dust), between the T Tauri stars and protostellar targets; the $M$(C)/$M$(dust) ratio of the T Tauri stars is one order of magnitude smaller than that of the protostars. The decrease of the estimated $M$(C)/$M$(dust) ratios for the disk sources is consistent with a theoretical prediction that the atomic C can survive only in the near surface layer of the disk and C$^+$/C/CO transition occurs deeper into the disk midplane.

Calibration of QM-MOURA three-axis magnetometer and gradiometer

Abstract. MOURA instrument is a three-axis magnetometer and gradiometer designed and developed for Mars MetNet Precursor mission. The initial scientific goal of the instrument is to measure the local magnetic field in the surroundings of the lander i.e. to characterize the magnetic environment generated by the remanent magnetization of the crust and the superimposed daily variations of the field produced either by the solar wind incidence or by the thermomagnetic variations. Therefore, the qualification model (QM) will be tested in representative scenarios like magnetic surveys on terrestrial analogues of Mars and monitoring solar events, with the aim to achieve some experience prior to the arrival to Mars. In this work, we present a practical first approach for calibration of the instrument in the laboratory; a finer correction after the comparison of MOURA data with those of a reference magnetometer located in San Pablo de los Montes (SPT) INTERMAGNET Observatory; and a comparative recording of a geomagnetic storm as a demonstration of the compliance of the instrument capabilities with the scientific objectives.

디지털중계기의 부하경감 및 이득조정기능 분석을 통한 열진공시험결과 성능분석

Recently, the usage of the satellite is increased more and more in the areas that are communication, weather, marine, optical, radar etc. The functions of the Satellite are evolving from passive transponder to active transponder by the developing of a technology. Advanced countries in satellites install the DCAMP for increase of bandwidth efficiency, improvement of QoS by interference rejection. DCAMP includes many digital components in order to implement functions. Thus, these kinds of active transponders consume much more power compared to passive transponder and then increase the heat. In this paper, we discuss the TVAC test result of DCAMP in EQM(Engineering Qualification Model) level. The paper shows the test results of digital gain control in order to verify DCAMP status under the TVAC test. In addition, the temperature and heat condition of main components from viewpoint of derating will be treated through the official environment test for qualification.

Measurement and stability of the pointing of the BepiColombo Laser Altimeter under thermal load

The BepiColombo Laser Altimeter (BELA) has been selected to fly on ESA׳s BepiColombo mission to Mercury. The instrument will be the first European laser altimeter designed for interplanetary flight. This paper describes the setup used to characterize the angular movements of BELA under the simulated environmental conditions that the instrument will encounter when orbiting Mercury. The system comprises a laser transmitter and a receiving telescope, which can move with respect to each other under thermal load. Tests performed using the Engineering Qualification Model show that the setup is accurate enough to characterize angular movements of the instrument components to an accuracy of ≈10μrad. The qualification instrument is thermally stable to operate during all mission phases around Mercury proving that the transmitter and receiver sections will remain within the alignment requirements during its mission.

Design, fabrication and test of qualification model of wire thermal cutting based non-explosive separation device for a small satellite

In this paper, we address the design, fabrication and test of a qualification model of a wire thermal cutting based non-explosive actuation (NEA) device for a small satellite. The important design parameters such as maximum allowable preload and release time are investigated through theoretical analysis. After it is fabricated based on theoretical results, we implemented the mechanical performance tests to assure operability and reliability for the compact size NEA device. From the result of the mechanical performance tests such as maximum preload, shock level and release time tests, we found that the proposed NEA device can be operated under a preload of 1000 kgf within 550 ms stably and it generates a low shock of 58.57 G. The margin calculation shows that the proposed NEA device can hold a solar panel of 20 kg with a margin of safety ( MS) of +0.32. In addition, we carried out the environment tests such as the vibration test and thermal vacuum test to qualify the proposed NEA device. From the vibration test, we found the resonant shapes after sine and random vibration were the same which means the proposed NEA device was successfully designed to have a stable structure. From the result of the thermal vacuum test, in addition, the proposed NEA device was well operated in a space environment condition.

A compact non-explosive separation device for high preload and low shock

In this paper, we present a compact non-explosive actuator device (NEA) that is activated with a thermal cutting method using Ni-Cr wire. Practical applications include the deployment of satellite appendages such as solar array panels and antennae. The pyrotechnic based separation device generates high shock and chemical contaminants, which cause malfunctions of components such as optic cameras and other sensors. The proposed NEA device is designed to generate low shock using unspool mechanism characteristic, and to have compact dimensions and a light mass. In the design process, we formulated equations based on a static analysis to verify that it satisfied the basic requirements. Then we fabricated the device based on a theoretical analysis and carried out pre-tests such as maximum preload and response time tests to verify the results of the theoretical analysis. The pre-test results showed an average maximum preload of 1,000 kgf and a response time of 600 ms. Consequently, we verified the feasibility of an NEA that could be activated within 600 ms under high preload. In order to develop a qualification model for the NEA, various additional tests are planned, including launching and space environment tests based on the European Satellite Agency standard test manual.

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The specifics of competence-based management in training students for the Master�s Degree in higher education pedagogy are revealed. The author argues for the necessity to replace the qualification model of higher education establishment graduate with the competence model and emphasizes the need to develop sophisticated methods to manage the professional competence building of prospective high-school teachers. The competence-based management is defined and its specific characteristics are highlighted to confirm that it is a separate form of higher education institution�s management. The original model for managing the process of building professional competence in the high-school pedagogy is described with its main ingredients: methodological, substantive and organizational and technological. The author lists the regulatory, managerial and organizational-and-pedagogic conditions for effective model performance and describes how to implement the proposed model and to set up evaluative and analytical monitoring of the model performance.

Qualification of the Liquid Metal Ion Source Instruments for the NASA MMS Mission

The instruments for active spacecraft potential control to be launched with the NASA Magnetospheric Multiscale (MMS) mission in 2014 have recently been qualified, and the first two out of a total of eight flight models have completed their acceptance test campaign. At the heart of these instruments are liquid metal ion sources with indium, developed at Forschungsund Technologietransfer GmbH. Earlier versions have been flown in the Equator-S, Cluster, and Double Star missions. The redesign efforts to comply with the stringent requirements of the MMS mission are described in detail, as well as the qualification program for the emitters and the instruments. Starting with mechanical and thermal analyses and tests, continuing with performance and life testing, and finally by analysis of the overall performance in the mission application, it can be demonstrated that the new generation of ion emitters beats the performance of previous versions in all aspects. The description of verification efforts is completed by the results from tests at instrument level of the qualification model and the first flight models.

End-to-end validation process for the INTA-Nanosat-1B Attitude Control System

This paper describes the end-to-end validation process for the Attitude Control Subsystem (ACS) of the satellite INTA-NanoSat-1B (NS-1B). This satellite was launched on July 2009 and it has been fully operative since then. The development of its ACS modules required an exhaustive integration and a system-level validation program. Some of the tests were centred on the validation of the drivers of sensors and actuators and were carried out over the flying model of the satellite. Others, more complex, constituted end-to-end tests where the concurrency of modules, the real-time control requirements and even the well-formedness of the telemetry data were verified. This work presents an incremental and highly automatised way for performing the ACS validation program based on two development suites and an end-to-end validation environment. The validation environment combines a Flat Satellite (FlatSat) configuration and a real-time emulator working in closed-loop. The FlatSat is built using the NS-1B Qualification Model (QM) hardware and it can run a complete version of the on-board software with the ACS modules fully integrated. The real-time emulator, running on an industrial PC, samples the actuation signals and emulates the sensors signals to close the control loop with the FlatSat. This validation environment constitutes a low-cost alternative to the classical three axes tilt table, with the advantage of being easily configured for working under specific orbit conditions, in accordance with any of the selected tests. The approach has been successfully applied to the NS-1B in order to verify different ACS modes under multiple orbit scenarios, providing an exhaustive coverage and reducing the risk of eventual errors during the satellite's lifetime. The strategy was applied also during the validation of the maintenance and reconfiguration procedures required once the satellite was launched. This paper describes in detail the complete ACS validation process that was performed and it shows the most relevant errors detected and fixed during testing. Finally it summarises some of the most significant conclusions.

European Experimental Reentry Testbed Winglet: From In-Flight Characterization to SCIROCCO Test

Thiswork is dedicated to the aerothermodynamic characterization, both inflight and atwind-tunnel conditions, of the ultrahigh temperature ceramic winglet that will embark on the European Experimental Reentry Testbed of the European Space Agency. The experimental test has been executed in the Centro Italiano Ricerche Aerospaziali SCIROCCO plasma wind tunnel on a winglet qualification model. The aim of the test was to reproduce the total thermal load,which thewingletwill be subjected to during the reentry trajectory, allowing preflight qualification and verification of materials and sensing equipment. Detailed three-dimensional computations in plasma-wind-tunnel conditions have allowed the verification of the test requirements and provided information about the physical phenomena that can cause dangerous local overpressures and overheatings on the capsule thermal protection system.The actual test condition has been rebuilt after the test bymeans of three-dimensional simulations; particular attention has been paid in modeling surface catalysis and emissivity. Finally, the aerothermodynamic code has been coupled with a thermal code to account for material thermal conduction. Numerical results have been compared in terms of pressure and temperature with experimental measurements showing good agreement.

MIRIS 충격시험에서의 광학계 안정성 확보를 위한 연구

MIRIS, Multi-purpose Infra-Red Imaging System, is the main payload of STSAT-3 (Korea Science & Technology Satellite 3), which will be launched in the end of 2012 (the exact date to be determined) by a Russian Dnepr rocket. MIRIS consists of two camera systems, SOC (Space Observation Camera) and EOC (Earth Observation Camera). During a shock test for the flight model stability in the launching environment, some lenses of SOC EQM (Engineering Qualification Model) were broken. In order to resolve the lens failure, analyses for cause were performed with visual inspections for lenses and opto-mechanical parts. After modifications of SOC opto-mechanical parts, the shock test was performed again and passed. In this paper, we introduce the solution for lens safety and report the test results.

Software Reliability Qualification Model

Software Reliability Qualification Model

Numerical Simulation and Testing of Water Impact of Structural Attachment Elements of a Reusable Thermal Protection System

Multiple mission reuse capability has become extremely important, towards reducing costs of space transportation. Carbon / Carbon (C/C) composites are well proven, functionally, for repeated use in re-entry missions. A re-entry capsule with sphere-cone-flare external shape, currently under realisation, will fly with C/C Thermal Protection System (TPS) in its peak heating region. The biggest challenge in design of such a reusable hot structure TPS is the management of thermo-structural loads. Differential Coefficient of Thermal Expansion (CTE) is the main cause of stress on the structural assembly elements. A set of flexible super alloy attachment brackets have been configured to take care of this differential thermal expansion of various TPS elements. The brackets also have to survive the impact transient load, on splashdown. This load was estimated using explicit non linear Finite Element method by considering the whole structure a rigid body. A separate FE model with actual stiffness of the structural attachments and the hot structure was generated, to predict the stresses caused by the load. In order to demonstrate the margins and survivability of the assembly, as a whole, a water impact test with actual qualification model of the assembly was carried out in a 10 m deep shock tank. The test also helped to validate the prediction. Considering factors such as cost, time and process constraints involved in realising C/C TPS for the test, it was decided to replace the same with an equivalent structure that satisfied all design and functional requirements. The test article was dropped vertically to simulate an impact velocity of 12 m/s and was adequately instrumented with accelerometers and strain gauges. The test results correlate reasonably well with the prediction.

Qualifciation test series of the indium needle FEEP micro-propulsion system for LISA Pathfinder

The Laser Interferometer Space Antenna project (LISA) is a co-operative program between ESA and NASA to detect gravitational waves by measuring distortions in the space–time fabric. LISA Pathfinder is the precursor mission to LISA designed to validate the core technologies intended for LISA. One of the enabling technologies is the micro-propulsion system based on field emission thrusters necessary to achieve the uniquely stringent propulsion requirements. A consortium consisting of Astrium GmbH and the University of Applied Sciences Wiener Neustadt (formerly AIT) was commissioned by ESA to develop and qualify the micro-propulsion system based on the Indium Needle FEEP technology. Several successful tests have verified the proper Needle Field Emission Electric Propulsion (FEEP) operation and the thermal and mechanical design of subcomponents of the developed system. For all functional tests, the flight representative Power Control Unit developed by SELEX Galileo S.p.A (also responsible for the Micro-Propulsion Subsystem (MPS) development) was used. Measurements have shown the exceptional stability of the thruster. An acceptance test of one Thruster Cluster Assembly (TCA) over 3600 h has shown the stable long term operation of the developed system. During the acceptance test compliance to all the applicable requirements have been shown such as a thrust resolution of 0.1 μN, thrust range capability between 0 and 100 μN, thrust overshoot much lower than the required 0.3 μN+3% and many others. In particular important is the voltage stability of the thruster (±1% over the duration of the testing) and the confirmation of the very low thrust noise. Based on the acceptance test the lifetime of the thruster is expected to exceed 39,000 h generating a total impulse bit of 6300 Ns at an average thrust level of 50 μN. A flight representative qualification model of the Needle FEEP Cluster Assembly (DM1) equipped with one active TCA has performed a qualification program consisting of acceptance, vibration, shock, and thermal vacuum test. During the last test, the thermal vacuum test (TVT), a performance decrease was observed. According to a preliminary analysis, this performance decrease is not linked to the thermal conditions simulated in the TVT but might be rather linked to secondary effects of the TVT set-up.

Spectral calibration of scanning sky monitor on ASTROSAT

Scanning Sky Monitor (SSM) on-board ASTROSAT is an X-ray detector in the energy range 2–10 keV to monitor the sky for transient X-ray sources. The science objective of SSM is to detect and locate these transient X-ray sources. We discuss here in this paper, the spectral calibration of SSM along with on-board calibration plans using the X-ray flux from the Crab nebula. Spectral response for SSM is derived using a routine in ftools and the inputs for deriving the response are got from the results of the experiments done on the qualification model for SSM.

POLAR: A Space-borne X-Ray Polarimeter for Transient Sources

POLAR is a novel compact Compton X-ray polarimeter designed to measure the linear polarization of the prompt emission of Gamma Ray Bursts (GRB) and other strong transient sources such as soft gamma repeaters and solar flares in the energy range 50-500 keV. A detailed measurement of the polarization from astrophysical sources will lead to a better understanding of the source geometry and emission mechanisms. POLAR is expected to observe every year several GRBs with a minimum detectable polarization smaller than 10%, thanks to its large modulation factor, effective area, and field of view. POLAR consists of 1600 low-Z plastic scintillator bars, divided in 25 independent modular units, each read out by one flat-panel multi-anode photomultiplier. The design of POLAR is reviewed, and results of tests of one modular unit of the engineering and qualification model (EQM) of POLAR with synchrotron radiation are presented. After construction and testing of the full EQM, we will start building the flight model in 2011, in view of the launch foreseen in 2013.

과학기술위성 3호 대용량 메모리 유닛의 인증모델 설계 및 구현

본 논문에서는 개발된 과학기술위성3호 대용량 메모리 유닛의 검증모델의 성능 및 환경시험 결과를 나타내었다. 과학기술위성3호 대용량 메모리 유닛은 적외선 영상시스템(MIRIS)과 초소형 영상 분광기(COMIS)에서 최대 100Mbps로 수신한 데이터를 32Gb의 메모리에 저장한 후 지상으로 10Mbps의 속도로 전송하는 임무를 수행한다. 탑재체 데이터 수신 시험과 데이터 수신 시스템으로의 데이터 전송 시험을 통해서 성능을 검증 하였다. 또한 발사체 환경과 우주 환경에서의 성능 확인을 위해서 진동 시험과 열진공 시험을 수행 하였다. This paper describes the design and test results of engineering qualification model(EQM) of mass memory unit(MMU) for STSAT-3. The MMU for STSAT-3 having 32Gb mass memory capacity is capable of receiving and transmitting the mission data from MIRIS(Multi-purpose IR Imaging System) and COMIS(Compact Imaging Spectrometer) at 100Mbps and 10Mbps. The performance of EQM MMU was verified by the tests of data receiving from two payloads and data transmission to the data receiving system. Moreover, the vibration and thermal vacuum test was performed to verify the launch vehicle and space environments.

Radiation-Pattern Measurements and Predictions of the PLANCK RF Qualification Model [AMTA Corner

PLANCK is one of the scientific missions of the European Space Agency, devoted to observing the cosmic microwave background radiation with unprecedented accuracy. One of the key factors for the performance is the radiation pattern of the telescope, especially the sidelobe performance in the direction of hot celestial bodies such as the sun, Earth, and moon. The satellite will operate around the L2 Lagrangian point in deep space under cryogenic conditions. These conditions cannot be realized in an antenna test range for a payload of this size. The predictions for the performance under flight conditions therefore depend strongly on numerical simulations. The model to be used had never before been verified to this level of confidence. The challenge was to conduct a test campaign at frequencies up to 320 GHz (far beyond the normal range of the used CATR) with a very large object (the PLANCK RF Qualification Model with an aperture size of 1.5 m, i.e., more than 1500 wavelengths at 320 GHz) to demonstrate sidelobe levels down to -90 dB. A selection of the measurement results and comparisons with predictions are presented.