Nanosatellite In Orbit Research Articles

Maintenance satellite modular docking mechanism design for on orbit servicing to nanosatellites

PurposeAs a result of space debris problem, it is necessary to deorbit uncontrollable satellites or repair them to extend mission duration to avoid sending a new satellite. The purpose of this paper is to develop a docking mechanism that can be easily customized for different missions, providing on-orbit servicing for nanosatellites.Design/methodology/approachThis research outlines a system and mechanism design for the docking phase of on-orbit servicing to nanosatellites. The umbrella-inspired mechanism is designed with utmost simplicity to minimize the likelihood of failure. CAD, structural analyse and mechanism analyse tools are used for designing and analysing the system. To ensure that the design attains the desired durability, numerous iterations are conducted. A three-dimensional (3D)-printed prototype is generated for mechanism verification in laboratory conditions.FindingsThe aimed mechanism is generated successfully. A 3D-printed prototype is assembled to verify the mechanism. Also, an equation for customis the presented design is generated for different mission requirements in the future.Practical implicationsThe usage of the proposed design can help increase the lifespan of satellites.Originality/valueThe primary innovation in this study is the development of a docking mechanism featuring a movable platform to provide servicing for nanosatellites in orbit. The mechanism presented can be displaced without initiating the unfolding process. This provides a customizable coupling distance for different mission requirements. Therefore, the presented mechanism can serve both different types of satellites and more than one satellite on-orbit with a cost-effective design. Also, the presented design can be easily customized to enable adaptation for the different mission requirements in the future.

CONCEPTUAL MODEL OF A NANOSATELLITE WITH LASER BEAM TRANSMISSION AND ITS IMPORTANCE IN RENEWABLE ELECTRICAL POWER HARVESTING

The concept of placing huge solar-powered satellite systems (SPS) in space represents one of several new technology options that could provide large-scale, green base power to terrestrial markets. NASA has already launched the multi-megawatt SSP systems and wireless power transmission (WPT) for government missions and commercial markets (in space and on the ground). In the new space approach satellite technology Nanosatellites with benefits such as low price, resource use, and compatibility with COTS, have huge potential to be the next generation of renewable electrical solar power harvesting satellite systems. With that in mind, it is important to conduct research and development processes for achieving high-efficiency satellite systems. As a result, an initial conceptual model of the new generation low earth orbit nanosatellite with solar power harvesting to laser beam conversion and transmission sub-system was developed with an estimated solar radiation harvesting calculus, part selection along with the structural scheme and its working principle have been proposed.

System Analysis and Design for Multiconverter Electrical Power Systems in Nanosatellites

For low-Earth orbit nanosatellite development, small volume and high reliability are of primary concern. The electrical power system (EPS) is a critical subsystem that generates, stores, and distributes power within the nanosatellite. An EPS is typically made up of multiple power converters that are designed independently and then connected together. However, if the impedance interactions of the power converters are not properly analyzed, the converters can interact adversely in some conditions, leading to instability. Analyses using the impedance interaction factor and the extra element theorem are applied to the EPS. A design procedure and analysis tool, developed in MATLAB, is presented to ensure a robust EPS without converter interaction stability problems. A CubeSat EPS hardware prototype with four buck converters powered by photovoltaic panels is tested to verify the impedance analysis and stable system operation of the nanosatellite EPS.

Polarization insensitive split square ring resonator based epsilon-negative and near zero refractive index metamaterial for S, C, and X frequency bands satellite and radar communications

This study has investigated the impact of inverse G-like shape resonators that exhibited epsilon negative (ENG) and near-zero refractive index (NZI) properties for multi-band wireless communications applications. The electrical measurement of structure is 0.118λ × 0.118λ × 0.021 λ, which is calculated at 3.94 GHz. FR-4 is used as a substrate layer, and the resonator is designed on it. This structure is manifested in the ENG and NZI characteristics within the frequency range of 3.8–4.17, 7.68–8.54, 10.67–11.36 GHz, and 4.07–4.15 and 8.29–8.37 GHz, respectively. This study also manifests the polarization insensitivity nature of 0°–90°, and the incident angle is investigated up to 60° for both TE and TM modes. The proposed structure achieves triple resonance at 3.94 GHz, 8.08 GHz, and 11.17 GHz, respectively, included in the S, C, and X frequency bands. The CST Microwave Studio 2019 software is conducted to design, develop, perform analysis, investigate electromagnetic properties, and extract effective medium parameters. The Advanced Design Software (ADS) is used to model the equivalent circuit of the unit cell. The simulated, measured, and ADS results verified the scattering parameter performance. The EMR value of the structure is 8.47, indicating the structure's compactness. The compact design with simplicity, ENG, and NZI properties make the proposed structure significant for microwave application, mainly to enhance the antenna bandwidth and gain filter design. ENG and NZI properties the operation frequency stability and efficiency for low earth orbit nanosatellite communications.

NANOSATELLITE MOTION SIMULATION FOR TESTING THE SUN SENSOR

Nanosatellite (NS) began to perform complex missions that require high orientation. In this research, we developed a mathematical model of solar sensors to determine the orientation of a NS. Various moments of obtaining the angle of the sun's rays when they hit the solar sensors were presented. The test results of the solar sensors used to simulate various orbit scenarios are described in detail, and graphs of the solar sensor readings are plotted based on the results obtained. The article deals with modeling the motion of a NS in orbit. The NS is equipped with 6 solar panels. The VTS software was used to simulate the motion of the NS. Also, in the study of determining the orientation, two different problems were considered, that is, when the satellite is in the shadow part of the earth and when it is in the solar part of the earth. For these tasks, a mathematical model for determining the orientation was built. This method is very relevant for the study of small spacecraft.

High-precision orbit determination for a LEO nanosatellite using BDS-3

The Tianping-1B is a 20-kg low earth orbit nanosatellite with a commercial multi-GNSS receiver based on a microelectromechanical system. This receiver collects concurrent code and phase dual-frequency measurements from the global positioning system (GPS) and the second and third generations of the BeiDou Global Navigation Satellite System (i.e., BDS-2 and BDS-3). However, BDS-3 signals with pseudorandom noise code numbers greater than 32 cannot be received. In this study, onboard GPS and BDS measurements from Tianping-1B are collected for days 133–147 of 2019. The performance of the onboard BDS-3 measurements is analyzed, and the potential of the BDS-3-based precise orbit determination (POD) for Tianping-1B is assessed. The carrier-to-noise-density ratio of the BDS-3 is higher than that of the BDS-2 and approaches that of the GPS. The BDS-3 has a smaller code multipath error than the BDS-2 and the GPS and therefore a higher quality of code measurements. The results of the overlap comparison show a GPS-based orbit consistency below 3.5 cm in three dimensions (3D) and below 1.2 cm in the radial direction. The mean of satellite laser ranging validation residual RMS is 1.7 cm. The orbit obtained using onboard BDS measurements is assessed using the GPS-based orbit as a reference: The mean 3D root mean square (RMS) difference between the BDS-3-only-based POD and the reference orbit is 4.57 cm. Thus, a sub-dm-level orbit can be achieved using only onboard BDS-3 measurements. A POD with slightly higher precision than the BDS-3-only-based POD is obtained using both BDS-3 and BDS-2 measurements, using higher weights for the BDS-3 data than the BDS-2 data. Then, the combined BDS-3/GPS POD is performed: The RMS difference between this joint orbit and the GPS-based orbit is 1 cm in 3D. This study can be used as a reference for the development of BDS-3 based POD, which will approve in accuracy and precision upon completion of BDS-3.

Speed-adaptive dynamic surface attitude control for a satellite with moving masses under input constraints

This paper investigates an attitude control technique for a low Earth orbit nanosatellite with moving masses based on the active use of aerodynamic forces. A speed-adaptive dynamic surface control scheme is designed to comprehensively solve the practical problems of aerodynamic model error, the dynamic effect of movement, stroke limitation, and slow convergence. Multiple constraints are imposed on the inputs to reduce the fast-varying dynamic effect of the masses to be negligible. Other slow-varying disturbances are precisely estimated by a nonlinear observer. In particular, to resolve the contradiction between the overshoot and the attitude convergence speed, a novel adaptive law is designed based on the smooth hyperbolic tangent function to adjust the convergence parameter within the given boundary. Moreover, considering the actual physical limitation, hard constraints are imposed on two actuators. Finally, by using the Lyapunov approach, it is proven that, despite uncertain dynamics, unknown disturbances and input constraints, the attitude error can be adjusted to be arbitrarily small by choosing the proper parameters. A semi-physical simulation platform is built to verify the feasibility of the moving mass actuator and the effectiveness and robustness of the proposed control scheme.

Near-zero metamaterial inspired UHF antenna for nanosatellite communication system

Epsilon-and-mu-near-zero (EMNZ) metamaterial structure inspired UHF antenna for nanosatellite has been proposed in this paper. The antenna consists of 3 × 2-unit cell array on the ground plane and a meander line radiating patch. Coaxial probe feeding technique has been obtained to excite the antenna. The meander line enables the antenna to resonate at lower UHF band and the metamaterial array is used to make the resonant frequency stable by reducing the coupling effect with metallic nanosatellite structure. The metamaterial structure exhibits EMNZ characteristics from 385 MHz to 488.5 MHz, which facilitates stable resonant frequency and higher antenna efficiency when embedded with nanosatellite structure. The proposed EMNZ inspired antenna has achieved measured impedance bandwidth (S11 < −10 dB) of 14.92 MHz (391 MHz–405.92 MHz). The perceptible novelty of this paper is the development of EMNZ metamaterial that significantly improves the UHF antenna’s operating frequency stability as well as efficiency for low earth orbit nanosatellite communications.

Towards LST split-window algorithm FPGA implementation for CubeSats on-board computations purposes

ABSTRACTNano, pico, and the so-called CubeSat satellites are taking place due to the emergent improvements in both high-performance nano and pico electronics and computational technologies. More than 1600 nanosats and CubeSats exist nowadays (i.e. 685 nanosats launched, 613 CubeSats launched, 405 nanosatellites in orbit, 321 operational nanosatellites, 71 nanosats destroyed on launch, etc.), with an incredible panoply of different constellations, governmental and non-governmental, high and easy to reach technologies, instruments in miniatures and missions from the military to universities and schools. This paper describes an approach to the implementation of the land surface temperature split-window (LST-SW) (Sobrino and Raissouni, IJRS 2000) algorithm structure based on the field programmable gate array (FPGA) technology. Due to the ever-increasing integrated circuit fabrication capabilities, the future of FPGA technology promises both higher densities and higher speeds for CubeSats on-board computations purposes. The research application shows the advantages of the used Xilinx Virtex-5 LX50 series FPGA approach in the LST-SW implementation with higher sampling rates than what is available from existing digital signal processing (DSP) chips, lower costs than an application specific integrated circuits (ASIC) for moderate volume applications and more flexibility than the alternate approaches. Since many current FPGA architectures are in-system programmable, the configuration of the device may be changed to implement different functionalities if required depending on the LST-SW parameters for each corresponding author. Finally, preliminary results show that the proposed LST-SW Xilinx Virtex-5 LX50 FPGA implementation approach is exceedingly flexible. Moreover, this implementation provides a considerable and promising performance that is suitable for future CubeSats on board LST-SW computations purposes.

Inflatable antenna for a nanosatellite

A topical problem for near-Earth orbit nanosatellites is the creation of a reliable inflatable antenna. The nanosatellite antenna should be small-sized and should take the given form after launching into orbit. This paper proposes a technology for manufacturing an inflatable antenna from prepreg which is hardened in space orbit. At the same time, all the advantages of inflatable antennas are preserved (small volume and weight, simplicity of design and reliability of bringing into working condition, long-distance steady communication). Small dust particles moving at cosmic speeds cannot damage such an antenna. There is also no need to constantly pump gas into the inflatable elements of the antenna, hence there is no need for mechanisms to provide adjustment of gas supply, additional tanks with gas or tanks with chemical elements to obtain it. The process of selecting a suitable reaction mixture for pre-preg hardening is considered in the paper, the main criteria for the selection being low volatility of its components and hot hardening ability. The results of stratospheric balloon flight with pre-preg samples are given. The design of the inflatable antenna is proposed.

AVIS Space Experiment: Testing of Technologies for the Development and Use of Multifunction Pico- and Nanosatellite Platforms

The paper briefly describes the Autonomous Video Information System (AVIS) space experiment conducted as part of the Long-Term Program of Applied Scientific Research and Experiments Planned on the Russian Segment of the International Space Station (ISS RS). The program envisages the development, production, and flight tests of a picosatellite prototype and a sequence of three nanosatellite prototypes with gradually increasing functionality. The main stages include the development of methods and instruments for controlling the separation of the spacecraft, monitoring of their state in an autonomous mode, and experimental testing of the technology of separation, rendezvous, and docking of nanosatellites in orbit. The developed onboard equipment also includes a device for launching pico- and nanosatellites from the ISS RS, manually by an astronaut and by an automatic launcher for nanosatellites from the Progress transport cargo vehicle (TCV), at the command of the ISS or a ground control station. Currently, detailed working design documentation for the spacecraft and the launching device has been created within the experimental program, and work has begun on the production of experimental prototypes.

Nanobob: a CubeSat mission concept for quantum communication experiments in an uplink configuration

We present a ground-to-space quantum key distribution (QKD) mission concept and the accompanying feasibility study for the development of the associated low earth orbit nanosatellite payload. The quantum information is carried by single photons with the binary codes represented by polarization states of the photons. Distribution of entangled photons between the ground and the satellite can be used to certify the quantum nature of the link: a guarantee that no eavesdropping can take place. By placing the entangled photon source on the ground, the space segments contains “only” the less complex detection system, enabling its implementation in a compact enclosure, compatible with the 12U CubeSat standard ({sim}12~mbox{dm}^{3}). This reduces the overall cost of the project, making it an ideal choice as a pathfinder for future European quantum communication satellite missions. The space segment is also more versatile than one that contains the source since it is compatible with a multiple of QKD protocols (not restricted to entangled photon schemes) and can be used in quantum physics experiments, such as the investigation of entanglement decoherence. Other possible experiments include atmospheric transmission/turbulence characterization, dark area mapping, fine pointing and tracking, and accurate clock synchronization; all crucial for future global scale quantum communication efforts.

Preliminary Design of Nano Satellite for Regional Navigation System

A Low cost Regional Navigation Satellite System employing constellation of nano satellites has been proposed for Indonesian coverage. The constellation of Low Earth Orbit nano satellites off course will not be able to give better position fixed to the GPS. However, the design of navigation system has much lower in cost compare to the current navigation system. This paper tells about preliminary design of the proposed regional navigation satellite system. The results of our satellite design has 3 kg on its weight, 10 W on power requirement at the peak condition, and 2.7 years of lifetime. Payload communication of the satellite will use UHF and TT&C communication will use VHF. Total area of solar panel will be 0.11 m2.

High-Resolution NDVI from Planet’s Constellation of Earth Observing Nano-Satellites: A New Data Source for Precision Agriculture

Planet Labs (“Planet”) operate the largest fleet of active nano-satellites in orbit, offering an unprecedented monitoring capacity of daily and global RGB image capture at 3–5 m resolution. However, limitations in spectral resolution and lack of accurate radiometric sensor calibration impact the utility of this rich information source. In this study, Planet’s RGB imagery was translated into a Normalized Difference Vegetation Index (NDVI): a common metric for vegetation growth and condition. Our framework employs a data mining approach to build a set of rule-based regression models that relate RGB data to atmospherically corrected Landsat-8 NDVI. The approach was evaluated over a desert agricultural landscape in Saudi Arabia where the use of near-coincident (within five days) Planet and Landsat-8 acquisitions in the training of the regression models resulted in NDVI predictabilities with an r2 of approximately 0.97 and a Mean Absolute Deviation (MAD) on the order of 0.014 (~9%). The MAD increased to 0.021 (~14%) when the Landsat NDVI training image was further away (i.e., 11–16 days) from the corrected Planet image. In these cases, the use of MODIS observations to inform on the change in NDVI occurring between overpasses was shown to significantly improve prediction accuracies. MAD levels ranged from 0.002 to 0.011 (3.9% to 9.1%) for the best performing 80% of the data. The technique is generic and extendable to any region of interest, increasing the utility of Planet’s dense time-series of RGB imagery.

Analytical investigation of a nanosatellite panel surface temperatures for different altitudes and panel combinations

The thermal control of future nanosatellite will be challenging due to dedicated panel surface area for radiation. The thermal control concept is to keep the payload within allowable temperature ranges. In order to predict the temperature for a nanosatellite in orbit, a basic thermal model of the nanosatellite was designed and analyzed. A thermal control system of the nanosatellite at an altitude 600 km with an inclination of 98° is presented. A thermal analysis of the nanosatellite was also performed with different altitudes from 500 km to 2000 km. A thermal control analysis of CubeSat's passive thermal control system was conducted. A temperature distribution of the solutions was computed. All electronic equipment and structural parts were within allowable temperatures, except the batteries. The batteries were out of their allowed range of temperatures in the cold case condition. The results of the study showed that the panel surface temperature results for different altitudes and panel combination are highly sensitive by the chosen surface coating of the nanosatellite.

Disaster Monitoring Constellation Using Nanosatellites

In this paper, a constellation of four low earth orbit nanosatellites for disaster monitoring is presented; their small size, low cost, and short time development give them the opportunity to be widely selected. The space segment is based on existing subsystems that are assembled on the bottom part of a developed structure and present acceptable performance for the mission. The payload is a multispectral camera which fulfills the mission’s requirements (remote sensing). The ground segment is based on an existing modular ground station, used for the ALSAT-1 DMC, which will be adapted to fit with the specifications of the mission.

Aerothermodynamic Aspects of Railgun-Assisted Launches of Projectiles With Sub- and Low-Earth-Orbit Payloads

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A Railgun-concept for the launch of small payloads into low-Earth orbits is currently under investigation. The first major project milestone foresees a 32-MJ railgun system able to launch nonpropelled projectiles with experiments for high-atmospheric research to an altitude of 115 km. This will be followed by a system to launch single-stage rocket-propelled projectiles to put in orbit nanosatellites using a 3.4-GJ railgun with a length of 180 m. One of the main issues to be investigated is the extreme thermal conditions the projectile's surfaces are exposed to, namely high temperatures and high thermal loads. These are caused by friction and turbulent flow properties, when the projectile rushes through the dense Earth's atmosphere in less than 30 s. The important questions to be answered for the design of a hypersonic projectile are the determination of the duration, magnitude, and location of the maximum temperatures with respect to the projectile's surface and its corresponding internal structure. For the determination of the complicated physical conditions, a two-step approach is used. In a so-called predesign phase, the HF3T code of the DLR is applied to estimate time-dependent temperature changes on the projectile's surface and/or within the material's structure as a function of the trajectory parameters. Finally, the three-degree-of-freedom trajectory program TRAJECTORY 3D of DLR is used to generate a detailed time-dependent data set, which includes the values for projectile velocity, Mach and Reynolds numbers, and atmospheric properties as a function of altitude. This data set is exchangeable with the TAU code of DLR for the solution of the Navier–Stokes equations, enabling pseudo-unsteady flow solutions along the trajectory. The solutions resulting from both approaches are then compared with emphasis on the surface temperature distributions. This strategy allows the verification of the feasibility of the proposed design solution for the railgun </para>