Nano Satellites Research Articles

3D Printing of High Voltage Printed Wiring Boards

In the last decade, research has focused on 3D printing for not only creating conceptual models but functional end-use products as well. As patents for 3D printing expire, new low cost desktop systems are being adopted more widely. This trend is leading to products being fabricated locally and improving supply chain logistics. However, currently low cost 3D printing is limited in the number of materials used simultaneously in fabrication and consequently is confined to fabricating enclosures and conceptual models. For additively manufactured end-use products to be useful, supplementary features and functionalities will need to be incorporated in to the final structures in terms of electronic, electromechanical, electromagnetic, thermodynamic, and optical content. The University of Texas at El Paso has recently been reporting on embedding electronic components and electrical interconnect into 3D printed structures either by interrupting the process or by inserting the additional content after the structure has been built. However, only until recently and with an investment from the presidential initiative on Additive Manufacturing “America Makes” has there been a concentrated research focus on developing technology that produces multi-functionality. This presentation will describe a project in which copper wires were used to supply a short burst of energy at high voltages in order to activate electro-propulsion. Pulsed Plasma Thursters provided by Busek were demonstrated where one joule of energy was supplied at 2000 volts in order to ablate the thruster in a vacuum and provide precise micro-newton-levels of force - as required for attitude control in small and nano satellites.

Exploring Modular Architecture for Nano Satellite and Opportunity for Developing Countries

SPACE Technology has the potential to provide information, infrastructure and inspiration that meets national needs in developing countries like Bangladesh. Many countries recognize this; in response they are investing in new national satellite programs to harness satellite services. Technology related to space is one example of a tool that can contribute to development both by addressing societal challenges and by advancing a nation's technological capability. To cope up with the advanced world in space technology Bangladesh seems to be highly potential country for satellite, Robotics, embedded systems and renewable energy research. BRAC University, Bangladesh is planning to launch a nano satellite with the collaboration of KIT, Japan. The proposed nano satellite project mission is to experiment about social, commercial and agricultural survey needs in Bangladesh. Each of the proposed applications of the project will improve the lives of millions of people of Bangladesh and it will be a pathfinder mission for the people of this country. Another intention of this project is to create a cheap satellite based remote sensing for developing countries as the idea of large space systems is very costly for us therefore we have decided to make a Nano-satellite.

超小型衛星の衝撃試験レベル調整方法に関するシミュレーション

Development of small satellites (50kg or less) is undergoing all over the world. Regardless its size, any satellite has to be tested for space environment. Various environment tests, such as vibration, vacuum, low and high temperature are necessary. Especially, shock test is one of the most difficult tests. The shock test needs to satisfy the SRS (shock response spectrum) requirement imposed by the launcher. If the SRS obtained in the test does not exceed the SRS requirement level, the test is invalid. At the same time, the SRS level as low as possible while satisfying the requirement is desired to protect the satellite from the overstress. SRS obtained by an air-gun type shock machine was analyzed using a commercial finite element code (LS-DYNA) to investigate the SRS at low frequencies, 100 to 300Hz, which is very difficult to control in the actual test. The analysis showed that controlling the friction of the slide table is effective to change the slope of SRS at the low frequencies. The lower the friction, the higher slope of SRS is obtained.

Microfabricated electrospray emitter arrays with integrated extractor and accelerator electrodes for the propulsion of small spacecraft

Microfabricated electrospray thrusters could revolutionize the spacecraft industry by providing efficient propulsion capabilities to micro and nano satellites (1–100 kg). We present the modeling, design, fabrication and characterization of a new generation of devices, for the first time integrating in the fabrication process individual accelerator electrodes capable of focusing and accelerating the emitted sprays. Integrating these electrodes is a key milestone in the development of this technology; in addition to increasing the critical performance metrics of thrust, specific impulse and propulsive efficiency, the accelerators enable a number of new system features such as power tuning and thrust vectoring and balancing. Through microfabrication, we produced high density arrays (213 emitters cm−2) of capillary emitters, assembling them at wafer-level with an extractor/accelerator electrode pair separated by micro-sandblasted glass. Through IV measurements, we could confirm that acceleration could be decoupled from the extraction of the spray—an important element towards the flexibility of this technology. We present the largest reported internally fed microfabricated arrays operation, with 127 emitters spraying in parallel, for a total beam of 10–30 µA composed by 95% of ions. Effective beam focusing was also demonstrated, with plume half-angles being reduced from approximately 30° to 15° with 2000 V acceleration. Based on these results, we predict, with 3000 V acceleration, thrust per emitter of 38.4 nN, specific impulse of 1103 s and a propulsive efficiency of 22% with <1 mW/emitter power consumption.

Controlled percolation and optimal two-phase operations in large-scale networks of nanosatellites

The paper deals with the solution of applied problems with the help of clusters of simple nanosatellites (NS) united in a network, each of them incapable of onboard control of the center-of-mass motion and randomly distributed in a given area of coverage of a ground track interval.If this method of receiving information is used the set of NSs is required not only to study the characteristics of each NS but also to consider the characteristics of large-scale random clusters of objects forming a "complex network". The notion of controlled percolation of the coverage region implemented in two phases is introduced. During the first phase the stochastic base with comparatively small concentration of NSs is formed which does not provide stochastic percolation, while during the second one additional nanosatellites are introduced in intercluster intervals in an optimal way to achieve the shortest percolation path through stochastically formed NS clusters with a relatively small total number of NSs and minimum of total costs.

Earthquake Signature Detection Using Cubesat Technology

Cubesats play a vital role in development of new micro components being used in various micro/nano satellites. Cubesats have an effective small design and have the ability to get modified easily. Quakesat, a satellite being deployed by Space Systems Development Laboratory (SSDL) is used to study, detect, record, and downlink extremely low frequency (ELF) magnetic signals, which are used to predict earthquake activity. Quakesat is a live example of cubesat technology, uses non space application components and provides a low cost alternative to launch space missions and support nano satellite infrastructure in future.

SCCC Turbo Equalizer/Decoder for X-band Nano Satellite High-Speed Downlink System

Nano satellite technologies have been recognized as potential candidates for new satellite applications. We have developed a X-band downlink system for nano satellite employing Consultative Committee for Space Data Systems (CCSDS) 131.2-B-1 signaling formats with a modulation symbol rate of 100 Msps. Since nano satellites with a mass of less than 50 kg have more constraints than typical large satellites, the received signals of nano satellites tend to suffer much more distortion due to the system and channel constraints. To compensate for the distortion, several techniques have been developed to provide higher data rate than 100 Mbps for nano satellites. At the transmitter, a look-up table (LUT) based digital predistorter for memoryless AM/AM and AM/PM nonlinearities is designed to mitigate nonlinearity of power amplifier (PA) and IQ-imbalance of quadrature modulator. At receiver side, a soft interference canceller (SIC) turbo equalization combined with SCCC turbo decoder has developed to overcome nonlinear/linear distortion using iterative techniques. For 16-QAM modulation, a nonlinear compensation technique based on centroid estimation at the receiver is also developed to correct constellation points of received signals. The techniques are modeled and verified via computer simulation; therefore, the obtained results apply to the downlink system designs of the nano satellite, Hodoyoshi 4.

Dual attitude and parameter estimation of passively magnetically stabilized nano satellites

The attitude determination capability of a nano satellite is limited by a lack of traditional high performance attitude sensors, a result of having small budgets for mass and power. Attitude determination can still be performed on a nano satellite with low fidelity sensors, but an accurate model of the spacecraft attitude dynamics is required. The passive magnetic stabilization systems commonly employed in nano satellites are known to introduce uncertainties in the parameters of the attitude dynamics model that cannot easily be resolved prior to launch. In this paper, a batch estimation problem is formulated that simultaneously solves for the attitude of the spacecraft and performs parameter estimation on the magnetic properties of the magnetic materials using only a measurement of the solar vector. The estimation technique is applied to data from NASA Ames Research Center's O/OREOS nano satellite and the University of Michigan's RAX-1 nano satellite, where clear differences are detected between the magnetic properties as measured before launch and those that fit the observed data. To date this is the first known on-orbit verification of the attitude dynamics model of a passively magnetically stabilized spacecraft.

S192023 短期開発を実現する超小型衛星の熱設計法([S192-02]宇宙システムに関する実践的解決と知見の汎用化(2))

A guide for the thermal design of micro and nano satellites is proposed in order to complete the thermal design of micro and nano satellites for about 1 year. Two concepts of thermal design are considered to keep the temperature change of components within the design temperature range of components. One concept is to decrease the temperature change using the whole heat storage of the micro and nano satellite. The other is to decrease the temperature change of the inner structure where the components with the narrow design temperature range are mounted. The temperature of micro and nano satellites designed in the former concept is calculated using one-nodal analysis method. The temperature of micro and nano satellites designed in the latter concept is calculated using twonodal analysis method. The combinations of optical properties on structures and components to keep the temperature within the design temperature range of components are clarified using one- or two-nodal analysis. Then, the multinodal analyses are carried out to be designed in detail based on the optical properties clarified from the one-nodal analysis and two-nodal analysis. This guide of thermal design is applied to Hodoyoshi-1 satellite. Hodoyoshi-1 satellite is the micro satellite that is about 50 cm in width, 50 cm in depth, 50 cm in height, is about 50 kg in mass, has two inner plates, has solar cells on the body, flies on the sun-synchronous orbit of the 500 km of altitude and is pointing to the Earth. The thermal design of Hodoyoshi-1 satellite has been completed for about ten months. The validity of this procedure is confirmed and the problems of this procedure are clarified.

New and alternative approach for launching satellite into Low Earth Orbit (LEO) using the Railgun coupled levitation and gap system.

The railgun coupled levitation and gap system is a new and alternative approach for the launch of Nano satellite into the Low Earth Orbit (LEO). The technology has been developed because of the growing economic and environmental challenges. The approach is new but attractive. It has the potential to reduce the launch cost compare to the traditional small sounding rockets. This technology being eco-friendly doesn't affect the dense layer of atmosphere (Troposphere and Stratosphere) compared to the exhaust gases produced by present day rockets. The high rate of repetition, the reduced launch cost and eco-friendly features, marks it a more promising field.The present paper describes the main idea and functioning of such system. Along with, it discusses the practical feasibility of such a concept. The basic design, its functioning, launch and thrust system, propellant characteristics, flight mechanics and various thermal and pressure loads which the projectile will bear, are also covered in this paper. Lastly, the paper provides a schematic overview and feasibility of this technology.

S192022 太陽同期軌道を周回する超小型衛星の熱設計に関する研究([S19202]小型宇宙システム(2))

The thermal analyses of micro and nano satellites on sun-synchronous orbits are performed by using one nodal analysis. Three models of the satellites are considered. The size and mass of model A, B, C are respectively 0.1 m cube and 1 kg, 0.25 m cube and 25 kg, 0.5 m cube and 50 kg. The analyses are carried out under the conditions of the altitude of 300, 500, 700, and 1 000 km, and the local time of descending node (LTDN) from 6 to 12. The combinations of solar absorptivity and infrared emissivity in the case that the temperature of the satellite is within the allowable temperature range (273.15-313.15 K) increase with the larger parameter of the mass times the heat capacity over one area on surface of satellite. The combinations increase with the higher altitudes and decrease with larger LTDN. The combinations in the case of the orbits without an eclipse are larger than with an eclipse. These results are useful for the preliminary thermal design of micro and nano satellites.

Attitude Determination of Nano Satellite Based on Gyroscope, Sun Sensor and Magnetometer

With the fast development of nano-satellite applications, higher requirements on the method and accuracy for determining attitude of Nano-satellite are presented. Aiming at the accuracy requirements of attitude determination of sun-oriented mode of the nano-satellite, an integrated attitude sensor is built with combining of gyroscope, magnetometer and sun sensor. Furthermore, the extended Kalman filter is used to fuse measurement data from gyroscope, magnetometer and sun sensor. A simulation model of attitude determination is built, and a few simulations are performed. The simulation results show that the accuracy of the integrated attitude determination sensor proposed in this paper can meet the accuracy requirement (0.05. Deg.) of nano-satellite attitude determination.

Satellite operation improvement through efficient data combination in ground station networks

AbstractDue to the recent advances in miniaturization of small satellites, a huge amount of pico and nano satellite missions have been launched in the last years. In this scope also several projects related to networking of ground stations have been established, to increase access to the satellites and to improve operations performance. An important aspect for efficient usage of ground station resources is the application of modern data management methods. This work describes a new approach to efficiently combine data streams in academic ground station networks.

Flight Data of a Cu(In,Ga)Se2 Thin-Film Solar Cell Module without a Coverglass by a Nano Satellite

A CIGS solar cell module without a coverglass was demonstrated by a small satellite since October 2005. A coverglass is normally used to protect the cell performance from low-energy (<3MeV) protons in space. This mission evaluates the model to assess the cell performance of CIGS solar cells, which thus far exhibited no degradation by thermal annealing effect in space. Flight data indicates that the performance has showed no degradation for about 900 days.

Attitude Detection Method of Nano Satellite HIT-SAT by Fluctuation of Received Signal Strength

In recent years, many universities have already launched small satellite on-orbit. Attitude information is important for satellite operation. However, many nano-satellite communication systems used amateur radio by narrow bandwidth frequency segment. Therefore, down-link of attitude information is expected to require substantial time. In this paper, we propose establishment of the attitude estimation method by means of the received radio power. And, satellite attitude information being estimated from the fluctuation of the received power. Then, comparison of satellite data obtained from on-board sensors with ground experiment. One major problem in this approach is the effect of Earth's ionosphere. As the radio signal passes through the ionosphere, the polarization angle is rotated by the Faraday Effect. The detection of attitude by the radiation pattern has been assumed that inaccurate. However, we are get data the spin satellite of liner polarization antenna. As a result, we can estimate 0.12rad/s accuracy of angular velocity measurement. This method can be applied to the attitude detection of many small satellites.

Geospatial Remote Sensing Using Advanced Sensor Systems

ABSTRACTRecently, various nanoscale materials, devices, and systems with remarkable properties have been developed, with numerous unique applications in chem.-bio sensors, nanophotonics, and nanobiotechnology. This presentation covers satellite and aerial remote sensing science and methodologies employing nanotechnology based advanced sensor systems to improve performance, resolutions, and security. Increased demand on monitoring, surveillance due to global war on terrorism, weather prediction, and environmental pollution detection and monitoring have necessitated geospatial sensing with high accuracy, speed, and authenticity. Plasmonic interactions on the nanoscale and nanophotonics have produced new phenomena and technologies surpassing the realms of possibilities with conventional photonics and electronics. These new technologies could include high spatial resolution near-field imaging, high efficiency information processing and transferring, high capacity optical data storage, flexible- and high contrast displays, and precise detection, control and manipulation of nanoscale devices and integrated systems. Elements utilizing refractive or diffractive surfaces have found applications in novel sub-wavelength nanostructures satellites. The nanophotonics structures coupled with lightweight structures and advanced nanotechnology based sensors have resulted in launching of nano-satellites by several countries. The use of nanophotonics in space through the combination of micro, nano, integrated and fibre-optic technologies is to reduce susceptibility of the system to EMI, reduction in the weight of the signal cables (&lt; 1/20 of electrical), higher information transmission capacity (GHz), reduced weight and volume, opto-isolation of critical spacecraft subsystems, high speed optical processing of RF and microwave signals, low propagation loss, and enhanced security encryption capabilities. Carbon Nanotubes (CNTs) based field emission electron gun (FEG) employ low voltage for emission and are actively researched as cold cathode microwave generation devices. CNTs based composites provide light-weight and compact platform with mechanical and thermal robustness. Such satellite system can be placed in low Earth orbit (LEO) to medium Earth orbit (MEO) as multi-sensor satellite imagers with panchromatic, multi-spectral, area and hyper spectral sensors on a single focal plane array (FPA), to achieve medium to high resolution (2.5m to 15m) spatial sampling, wide swaths (up to 45km) and noise equivalent reflectance (NER) values of less than 0.5%. An evaluation of security risks, vulnerability, and strategies is presented for communications technologies used in gathering, processing, storing, and disseminating global environmental micro and nano sensors and satellite data.

HAUSAT-2 소형위성 열해석 검증 및 보드-레벨 열해석

HAUSAT-2는 한국항공대학교 우주시스템 연구실에서 개발하고 있는 25kg급의 소형위성 이다. 위성의 시스템과 부품의 안정적인 작동을 확인하기 위하여 위성의 시스템과 박스모듈 그리고 전장보드 수준에서 열해석을 수행하였다. 시스템과 박스-레벨 열해석에 적용한 열 모델링은 HAUSAT-2 구조-열 모델의 열진공/균형 시험을 통하여 검증 및 보정되었다. 본 연구에서는 주요 소자를 직접 모델링하는 방법의 보드-레벨 열해석 방법론을 제안하고, 그에 따른 결과 분석 및 타당성을 제시하였다. HAUSAT-2 is nano satellite with 25kg mass being developed by Space System Research Lab. in Hnakuk Aviation University. This paper addresses HAUSAT-2 small satellite thermal analyses and its verification at satellite system, electronic box, and PCB levels. Thermal model which is used for system-level and box-level thermal analyses was verified and corrected through thermal vacuum/balance test. The new board-level thermal analysis methodology, modelling high-power dissipating EEE parts directly, was proposed. The proposed methodology has been verified with test results.

An integrated micro HTS system for energy storage and attitude control for three-axis stabilized nanosatellites

This paper presents the development of an integrated micro high-temperature superconductor system for energy storage and attitude control of three-axis stabilized nano satellites. The micro HTS system consists of a flywheel/rotor, motor/generator, motor electronics, and a cooling system. The flywheel/rotor has been fabricated by using sintered NdFeB and the stator for motor/generator has been fabricated by micro fabrication technology. An alternative stator has been fabricated by cutting a 50 micron-thick copper film for comparison. A servo amplifier to drive the DC brushless motor of the integrated HTS system has been developed and successfully tested. A cooling system has been developed to test the system. It has been observed that the micro fabricated stator can make the flywheel rotate at a constant velocity of up to 12,000 rpm whereas the other stator generates a constant velocity of up to 2,500 rpm. Experiments show that the micro fabricated stator can significantly reduce the motor/generator losses.

University of Tokyo's Student Nano-Satellite Project CubeSat-XI and Its On-Orbit Experiment Results

Students of University of Tokyo, ISSL (Intelligent Space Systems Laboratory), developed a nano satellite named “CubeSat-XI,” which was successfully launched by Russian Rocket “ROCKOT” on June 30, 2003. The satellite has been working well and the students have been performing various experiments using this satellite. This paper reviews the concept, significance, systems' descriptions of CubeSat-XI, and reports the post-launch flight experiment results. Especially, orbit determination and estimation of the satellite attitude will be highlighted. Earth imaging mission will also be described.

B2 東京大学超小型衛星 CubeSat プロジェクトの成果について

CubeSat project has started primarily for an education purpose to improve student's skill of space engineering and project management. The CubeSat program at University of Tokyo, ISSL (Intelligent Space Systems Laboratory), has been started since 1999 and it's first nano satellite named "CubeSat-XI", developed by students, was successfully launched by a Russian rocket "ROCKOT" on June 30,2003. Since then, the satellite becomes operational and the students have been performing various experiments and demonstrations of its bus technologies and the onboard camera. This paper briefly reviews the systems description, the operation and the results achieved until present moment.