Tag Archives: Systems and Control

Schedule optimization for transiting exoplanet observations with NASA's Pandora SmallSat mission [IMA]

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http://arxiv.org/abs/2305.02285


Pandora is an upcoming NASA SmallSat mission that will observe transiting exoplanets to study their atmospheres and the variability of their host stars. Efficient mission planning is critical for maximizing the science achieved with the year-long primary mission. To this end, we have developed a scheduler based on a metaheuristic algorithm that is focused on tackling the unique challenges of time-constrained observing missions, like Pandora. Our scheduling algorithm combines a minimum transit requirement metric, which ensures we meet observational requirements, with a `quality’ metric that considers three factors to determine the scientific quality of each observation window around an exoplanet transit (defined as a visit). These three factors are: observing efficiency during a visit, the amount of the transit captured by the telescope during a visit, and how much of the transit captured is contaminated by a coincidental passing of the observatory through the South Atlantic Anomaly. The importance of each of these factors can be adjusted based on the needs or preferences of the science team. Utilizing this schedule optimizer, we develop and compare a few schedules with differing factor weights for the Pandora SmallSat mission, illustrating trade-offs that should be considered between the three quality factors. We also find that under all scenarios probed, Pandora will not only be able to achieve its observational requirements using the planets on the notional target list but will do so with significant time remaining for ancillary science.

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T. Foote, T. Barclay, C. Hedges, et. al.
Thu, 4 May 23
51/60

Comments: 35 pages, 7 figures. Submitted to JATIS, SPIE. Python code is available at: this https URL

Review of X-ray pulsar spacecraft autonomous navigation [IMA]

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http://arxiv.org/abs/2304.04154


This article provides a review on X-ray pulsar-based navigation (XNAV). The review starts with the basic concept of XNAV, and briefly introduces the past, present and future projects concerning XNAV. This paper focuses on the advances of the key techniques supporting XNAV, including the navigation pulsar database, the X-ray detection system, and the pulse time of arrival estimation. Moreover, the methods to improve the estimation performance of XNAV are reviewed. Finally, some remarks on the future development of XNAV are provided.

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Y. Wang, W. Zheng, S. Zhang, et. al.
Tue, 11 Apr 23
27/63

Comments: has been accepted by Chinese Journal of Aeronautics

Small Spacecraft for Global Greenhouse Gas Monitoring [CL]

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http://arxiv.org/abs/2212.07680


This work is devoted to the capabilities analysis of constellation and small spacecraft developed using CubeSat technology to solve promising problems of the Earth remote sensing in the area of greenhouse gases emissions. This paper presents the scientific needs for such tasks, followed by descriptions and discussions of the micro-technology application both in the small satellite platform design and in the payload design. The overview of analogical spacecraft is carried out. The design of a new spacecraft for determination the oxygen and carbon dioxide concentration in the air column along the line of sight of the spacecraft when it illuminated by reflected sunlight is introduced. A mock-up of the device was made for greenhouse gases remote sensing a Fourier Transform Infrared (FTIR) spectroradiometer is placed in the small spacecraft design. The results of long-term measurements of greenhouse gas concentrations using the developed Fourier spectrometer mock-up is presented.

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V. Mayorova, A. Morozov, I. Golyak, et. al.
Fri, 16 Dec 22
1/72

Comments: 8 pages, 4 figures, 2 tables

Calculation of the High-Energy Neutron Flux for Anticipating Errors and Recovery Techniques in Exascale Supercomputer Centres [CL]

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http://arxiv.org/abs/2212.07770


The age of exascale computing has arrived and the risks associated with neutron and other atmospheric radiation are becoming more critical as the computing power increases, hence, the expected Mean Time Between Failures will be reduced because of this radiation. In this work, a new and detailed calculation of the neutron flux for energies above 50 MeV is presented. This has been done by using state-of-the-art Monte Carlo astroparticle techniques and including real atmospheric profiles at each one of the next 23 exascale supercomputing facilities. Atmospheric impact in the flux and seasonal variations were observed and characterised, and the barometric coefficient for high-energy neutrons at each site was obtained. With these coefficients, potential risks of errors associated with the increase in the flux of energetic neutrons, such as the occurrence of single event upsets or transients, and the corresponding failure-in-time rates, can be anticipated just by using the atmospheric pressure before the assignation of resources to critical tasks at each exascale facility. For more clarity, examples about how the rate of failures is affected by the cosmic rays are included, so administrators will better anticipate which more or less restrictive actions could take for overcoming errors.

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H. Asorey and R. Mayo-García
Fri, 16 Dec 22
3/72

Comments: 23 pages, 6 figures, 2 tables

ATLAS: Deployment, Control Platform and First RSO Measurements [CL]

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http://arxiv.org/abs/2211.03586


The ever increasing dependence of modern societies in space based services results in a rising number of objects in orbit which grows the probability of collisions between them. The increase in space debris is a threat to space assets, space based-operations and led to a common effort to develop programs for dealing with it. As part of the Portuguese Space Surveillance and Tracking (SST) project, led by the Portuguese Ministry of Defense (MoD), Instituto de Telecomunica\c{c}\~oes (IT) is developing the rAdio TeLescope pAmpilhosa Serra (ATLAS), a new monostatic radar tracking sensor located at the Pampilhosa da Serra Space Observatory (PASO), Portugal. The system operates at 5.56 GHz and aims to provide information on objects in low earth orbit (LEO), with cross sections above 10 cm$^2$ at 1000~km. The sensor is tasked by the Portuguese Network Operations Center (NOC), located in the Azores island, which interfaces with the EU-SST network.

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J. Pandeirada, M. Bergano, P. Marques, et. al.
Tue, 8 Nov 22
68/79

Comments: 5 pages, 5 figures, 1 Apendix, Accepted for publication at the Proceedings of the 73rd International Astronautical Congress, Paris, Septembre 2022

Interstellar Object Accessibility and Mission Design [EPA]

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http://arxiv.org/abs/2210.14980


Interstellar objects (ISOs) are fascinating and under-explored celestial objects, providing physical laboratories to understand the formation of our solar system and probe the composition and properties of material formed in exoplanetary systems. This paper will discuss the accessibility of and mission design to ISOs with varying characteristics, including a discussion of state covariance estimation over the course of a cruise, handoffs from traditional navigation approaches to novel autonomous navigation for fast flyby regimes, and overall recommendations about preparing for the future in situ exploration of these targets. The lessons learned also apply to the fast flyby of other small bodies including long-period comets and potentially hazardous asteroids, which also require a tactical response with similar characteristics

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B. Donitz, D. Mages, H. Tsukamoto, et. al.
Fri, 28 Oct 22
47/56

Comments: Accepted at IEEE Aerospace Conference

SPHERExLabTools (SLT): A Python Data Acquisition System for SPHEREx Characterization and Calibration [IMA]

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http://arxiv.org/abs/2208.05099


Selected as the next NASA Medium Class Explorer mission, SPHEREx, the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer is planned for launch in early 2025. SPHEREx calibration data products include detector spectral response, non-linearity, persistence, and telescope focus error measurements. To produce these calibration products, we have developed a dedicated data acquisition and instrument control system, SPHERExLabTools (SLT). SLT implements driver-level software for control of all testbed instrumentation, graphical interfaces for control of instruments and automated measurements, real-time data visualization, processing, and data archival tools for a variety of output file formats. This work outlines the architecture of the SLT software as a framework for general purpose laboratory data acquisition and instrument control. Initial SPHEREx calibration products acquired while using SLT are also presented.

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S. Condon, M. Viero, J. Bock, et. al.
Thu, 11 Aug 22
7/68

Comments: 15 pages, 10 figures, proceedings for the 2022 SPIE Astronomical Telescopes and Instrumentation conference

Comparison of Deep Space Navigation Using Optical Imaging, Pulsar Time-of-Arrival Tracking, and/or Radiometric Tracking [CL]

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http://arxiv.org/abs/2205.08652


Recent advances with space navigation technologies developed by NASA in space-based atomic clocks and pulsar X-ray navigation combined with past successes in autonomous navigation using optical imaging, brings to the forefront the need to compare space navigation using optical, radiometric, and pulsar-based measurements using a common set of assumptions and techniques. This review article examines these navigation data types in two different ways. First, a simplified deep space orbit determination problem is posed that captures key features of the dynamics and geometry, and then each data type is characterized for its ability to solve for the orbit. The data types are compared and contrasted using a semi-analytical approach with geometric dilution of precision techniques. The results provide useful parametric insights into the strengths of each data type. In the second part of the paper, a high-fidelity, Monte Carlo simulation of a Mars cruise, approach, and entry navigation problem is studied. The results found complement the semi-analytic results in the first part, and illustrate specific issues such as each data type’s quantitative impact on solution accuracy and their ability to support autonomous delivery to a planet.

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T. Ely, S. Bhaskaran, N. Bradley, et. al.
Thu, 19 May 22
47/61

Comments: N/A

Towards on-sky adaptive optics control using reinforcement learning [IMA]

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http://arxiv.org/abs/2205.07554


The direct imaging of potentially habitable Exoplanets is one prime science case for the next generation of high contrast imaging instruments on ground-based extremely large telescopes. To reach this demanding science goal, the instruments are equipped with eXtreme Adaptive Optics (XAO) systems which will control thousands of actuators at a framerate of kilohertz to several kilohertz. Most of the habitable exoplanets are located at small angular separations from their host stars, where the current XAO systems’ control laws leave strong residuals.Current AO control strategies like static matrix-based wavefront reconstruction and integrator control suffer from temporal delay error and are sensitive to mis-registration, i.e., to dynamic variations of the control system geometry. We aim to produce control methods that cope with these limitations, provide a significantly improved AO correction and, therefore, reduce the residual flux in the coronagraphic point spread function.
We extend previous work in Reinforcement Learning for AO. The improved method, called PO4AO, learns a dynamics model and optimizes a control neural network, called a policy. We introduce the method and study it through numerical simulations of XAO with Pyramid wavefront sensing for the 8-m and 40-m telescope aperture cases. We further implemented PO4AO and carried out experiments in a laboratory environment using MagAO-X at the Steward laboratory. PO4AO provides the desired performance by improving the coronagraphic contrast in numerical simulations by factors 3-5 within the control region of DM and Pyramid WFS, in simulation and in the laboratory. The presented method is also quick to train, i.e., on timescales of typically 5-10 seconds, and the inference time is sufficiently small (< ms) to be used in real-time control for XAO with currently available hardware even for extremely large telescopes.

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J. Nousiainen, C. Rajani, M. Kasper, et. al.
Tue, 17 May 22
81/95

Comments: N/A

Desarrollo del software de interfaz de usuario para el espectrógrafo astronómico COLORES instalado en el observatorio de la Mayora [IMA]

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http://arxiv.org/abs/2205.05773


This thesis project arises from the need to put into operation the spectrograph (COLORES) of the station (BOOTES 2), located in La Mayora and belonging to the network of Burst Observer and Optical Transient Exploring System (BOOTES) telescopes. A robotic telescope such as the one located at BOOTES 2 has, among its many virtues, the ability to perform a multitude of observations with a very low reaction time. This makes it possible to obtain a large amount of data on the positioning and characterization of astronomical bodies. With this tool in operation, it will now be possible to extract a multitude of new parameters from the observations, providing this station with a more complete and versatile instrument with which to obtain more interesting scientific information.
For this task, a series of scripts will be performed. Specifically two, one for the calibration of the spectrograph and another one in charge of the image processing and the extraction of its spectrum. This will be carried out using Spyder software (Python), in which, in addition, numerous tests will be carried out to verify that the software works perfectly. Once these tests have been carried out, it will be implemented in the telescope’s Web page for its use.
Several libraries will be used for this purpose, including Astropy, which includes a complete package for handling astronomical data in Python, and Matplotlib, which allows the use of graphics generated from data contained in arrays. In addition, several image acquisition techniques will be used, such as: filtering, Gaussian adjustment, and use of regions of interferences. With all this, the data extracted from the telescope will be optimized to achieve the desired results.

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&. Martínez
Fri, 13 May 22
17/64

Comments: 78 pages, in Spanish language, 59 figures

RACIMO@Bucaramanga: A Citizen Science Project on Data Science and Climate Awareness [IMA]

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http://arxiv.org/abs/2203.05431


This paper describes a collaborative experience to empower organized communities to produce, curate and disseminate environmental data. A particular emphasis is done on the description of open hardware & software architecture and the processes of commissioning of the low cost Arduino-Raspberry-Pi weather station which measures: atmospheric pressure, temperature, humidity, precipitation, cloudiness, and illuminance/irradiance. The idea is to encourage more people to replicate this open-science initiative. We have started this experience training students & teachers from seven mid secondary schools through a syllabus of 12 two-hours lectures with a web-based support which exposes them to basic concepts and practices of Citizen Science and Open Data Science.

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J. Peña-Rodríguez, P. Salgado-Meza, H. Asorey, et. al.
Fri, 11 Mar 22
42/59

Comments: N/A

A novel method for adaptive control of deformable mirrors [CL]

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http://arxiv.org/abs/2203.04915


For sufficiently wide ranges of applied control signals (control voltages), MEMS and piezoelectric Deformable Mirrors (DMs), exhibit nonlinear behavior. The nonlinear behavior manifests itself in nonlinear actuator couplings, nonlinear actuator deformation characteristics, and in the case of piezoelectric DMs, hysteresis. Furthermore, in a number of situations, DM behavior can change over time, and this requires a procedure for updating the DM models on the basis of the observed data. If not properly modeled and if not taken into account when designing control algorithms, nonlinearities, and time-varying DM behavior, can significantly degrade the achievable closed-loop performance of Adaptive Optics (AO) systems. Widely used approaches for DM control are based on pre-estimated linear time-invariant DM models in the form of influence matrices. Often, these models are not being updated during system operation. Consequently, when the nonlinear DM behavior is excited by control signals with wide operating ranges, or when the DM behavior changes over time, the state-of-the-art DM control approaches relying upon linear control methods, might not be able to produce a satisfactory closed-loop performance of an AO system. Motivated by these key facts, we present a novel method for data-driven DM control. Our approach combines a simple open-loop control method with a recursive least squares method for dynamically updating the DM model. The DM model is constantly being updated on the basis of the dynamically changing DM operating points. That is, the proposed method updates both the control actions and the DM model during the system operation. We experimentally verify this approach on a Boston Micromachines MEMS DM with 140 actuators. Preliminary experimental results reported in this manuscript demonstrate good potential for using the developed method for DM control.

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A. Haber
Thu, 10 Mar 22
30/60

Comments: SPIE Proceedings, SPIE BiOS, 2022, San Francisco, California, United States, Proceedings Volume 11969, Adaptive Optics and Wavefront Control for Biological Systems VIII; 1196902

COSMIC: fast closed-form identification from large-scale data for LTV systems [CL]

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http://arxiv.org/abs/2112.04355


We introduce a closed-form method for identification of discrete-time linear time-variant systems from data, formulating the learning problem as a regularized least squares problem where the regularizer favors smooth solutions within a trajectory. We develop a closed-form algorithm with guarantees of optimality and with a complexity that increases linearly with the number of instants considered per trajectory. The COSMIC algorithm achieves the desired result even in the presence of large volumes of data. Our method solved the problem using two orders of magnitude less computational power than a general purpose convex solver and was about 3 times faster than a Stochastic Block Coordinate Descent especially designed method. Computational times of our method remained in the order of magnitude of the second even for 10k and 100k time instants, where the general purpose solver crashed. To prove its applicability to real world systems, we test with spring-mass-damper system and use the estimated model to find the optimal control path. Our algorithm was applied to both a Low Fidelity and Functional Engineering Simulators for the Comet Interceptor mission, that requires precise pointing of the on-board cameras in a fast dynamics environment. Thus, this paper provides a fast alternative to classical system identification techniques for linear time-variant systems, while proving to be a solid base for applications in the Space industry and a step forward to the incorporation of algorithms that leverage data in such a safety-critical environment.

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M. Carvalho, C. Soares, P. Lourenço, et. al.
Thu, 9 Dec 21
12/63

Comments: N/A

Dual-Update Data-Driven Control of Deformable Mirrors Using Walsh Basis Functions [CL]

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http://arxiv.org/abs/2111.03275


In this paper, we develop a novel data-driven method for Deformable Mirror (DM) control. The developed method updates both the DM model and DM control actions that produce desired mirror surface shapes. The novel method explicitly takes into account actuator constraints and couples a feedback control algorithm with an algorithm for recursive estimation of DM influence function models. In addition to this, we explore the possibility of using Walsh basis functions for DM control. By expressing the desired and observed mirror surface shapes as sums of Walsh pattern matrices, we formulate the control problem in the 2D Walsh basis domain. We thoroughly experimentally verify the developed approach on a 140-actuator MEMS DM, developed by Boston Micromachines. Our results show that the novel method produces the root-mean-square surface error in the $14-40$ nanometer range. These results can additionally be improved by tuning the control and estimation parameters. The developed approach is also applicable to other DM types, such as for example, segmented DMs.

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A. Haber and T. Bifano
Mon, 8 Nov 21
56/69

Comments: 25 pages, 11 figures

A Portuguese radar tracking sensor for Space Debris monitoring [IMA]

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http://arxiv.org/abs/2111.02232


The increase in space debris is a threat to space assets, space based-operations and led to a common effort to develop programs for dealing with this increase. As part of the Portuguese Space Surveillance and Tracking (SST) project, led by the Portuguese Ministry of Defense (MoD), the Instituto de Telecomunica\c{c}\~oes (IT) is developing rAdio TeLescope pAmpilhosa Serra (ATLAS), a new monostatic radar tracking sensor located at the Pampilhosa da Serra Space Observatory (ErPoB), Portugal. The system operates at 5.56 GHz and aims to provide information on objects in low earth orbit (LEO) orbits, with cross sections above 10 cm2 at 1000 km. ErPoB houses all the necessary equipment to connect to the research and development team in IT-Aveiro and to the European Union Space Surveillance and Tracking (EU-SST) network through the Portuguese SST-PT network and operation center. The ATLAS system features digital waveform synthesis, power amplifiers using Gallium Nitride (GaN) technology, fully digital signal processing and a highly modular architecture that follows an Open Systems (OS) philosophy and uses Commercial-Off-The-Shelf (COTS) technologies. ATLAS establishes a modern and versatile platform for fast and easy development, research and innovation. The whole system (except antenna and power amplifiers) was tested in a setup with a major reflector of opportunity at a well defined range. The obtained range profiles show that the target can be easily detected. This marks a major step on the functional testing of the system and on getting closer to an operational system capable of detecting objects in orbit.

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J. Pandeirada, M. Bergano, P. Marques, et. al.
Thu, 4 Nov 21
14/73

Comments: Manuscript presented at the International Astronautical Congress, IAC 2021, Dubai, United Arab Emirates, 25 – 29 October 2021. Copyright by IAF

Lunaport: Math, Mechanics & Transport [IMA]

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http://arxiv.org/abs/2107.14423


Issues for transport facilities on the lunar surface related to science, engineering, architecture, and human-factors are discussed. Logistic decisions made in the next decade may be crucial to financial success. In addition to outlining some of the problems and their relations with math and computation, the paper provides useful resources for decision-makers, scientists, and engineers.

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P. Kainen
Mon, 2 Aug 21
42/82

Comments: 45 pages, submitted to Symmetry, for Special Issue on Symmetry in Mechanical and Transport Engineering, Transport Logistics, and Mathematical Design of Efficient Transport Facilities

Design of the Propulsion System of Nano satellite: StudSat2 [CL]

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http://arxiv.org/abs/2107.10992


The increase in the application of the satellite has skyrocketed the number of satellites, especially in the low earth orbit. The major concern today is after the end of life, these satellites become debris which negatively affects the space environment. As per the international guidelines of the European Space Agency, it is mandatory to deorbit the satellite within 25 years of the end of life. StudSat1, which was successfully launched on 12th July 2010, is the first Pico satellite developed in India by undergraduate students from seven different engineering colleges across South India. Now, the team is developing StudSat2, which is India’s first twin satellite mission having two nanosatellites whose overall mass is less than 10kg. This paper is aimed to design the propulsion system, cold gas thruster, to deorbit StudSat2 from its original orbit i.e. 600 km to lower orbit i.e. 400km. The propulsion system mainly consists of a storage tank, pipes, Convergent Divergent nozzle, and electronic actuators. The paper also gives information about the components of cold gas thruster, which have been designed in the CATIA V5, and the structural and flow analysis of the same has been done in ANSYS. The concept of Hohmann transfer has been used to deorbit the satellite and STK has been used to simulate it.

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R. Sah, P. Sherpaili, A. Anand, et. al.
Mon, 26 Jul 21
18/62

Comments: 6 pages, 13 figures, Accepted and Presented in Proceeding of International Conference on Mechanical and Aerospace Engineering (ICMAE-17), Kathmandu, Nepal on 30th Dec 2017, ASAR International Conference

Constellation Design of Remote Sensing Small Satellite for Infrastructure Monitoring in India [CL]

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http://arxiv.org/abs/2107.09253


A constellation of remote sensing small satellite system has been developed for infrastructure monitoring in India by using SAR Payload. The LEO constellation of the small satellites is designed in a way, which can cover the entire footprint of India. Since India lies a little above the equatorial region, the orbital parameters are adjusted in a way that inclination of 36 degrees and RAAN varies from 70-130 degrees at a height of 600 km has been considered. A total number of 4 orbital planes are designed in which each orbital plane consisting 3 small satellites with 120-degrees true anomaly separation. Each satellite is capable of taking multiple look images with the minimum resolution of 1 meter per pixel and swath width of 10 km approx. The multiple look images captured by the SAR payload help in continuous infrastructure monitoring of our interested footprint area in India. Each small satellite is equipped with a communication payload that uses X-band and VHF antenna, whereas the TT&C will use a high data-rate S-band transmitter. The paper presents only a coverage metrics analysis method of our designed constellation for our India footprint by considering the important metrics like revisit time, response time, and coverage efficiency. The result shows that the average revisits time for our constellation ranges from about 15- 35 min which is less than an hour and the average response time for this iteratively designed constellation ranges from about 25-120 min along with hundred percent coverage efficiency most of the time. Finally, it was concluded that each satellite has 70kg of total mass and costs around $ 0.75M to develop.

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R. Sah, R. Srivastava and K. Das
Wed, 21 Jul 21
16/83

Comments: 10 Pages, 13 figure, Accepted for the Small Satellite Conference 2021

Applications And Potentials Of Intelligent Swarms For Magnetospheric Studies [IMA]

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http://arxiv.org/abs/2107.01601


Earth’s magnetosphere is vital for today’s technologically dependent society. To date, numerous design studies have been conducted and over a dozen science missions have own to study the magnetosphere. However, a majority of these solutions relied on large monolithic satellites, which limited the spatial resolution of these investigations, as did the technological limitations of the past. To counter these limitations, we propose the use of a satellite swarm carrying numerous and distributed payloads for magnetospheric measurements. Our mission is named APIS (Applications and Potentials of Intelligent Swarms), which aims to characterize fundamental plasma processes in the Earth’s magnetosphere and measure the effect of the solar wind on our magnetosphere. We propose a swarm of 40 CubeSats in two highly-elliptical orbits around the Earth, which perform radio tomography in the magnetotail at 8-12 Earth Radii (RE) downstream, and the subsolar magnetosphere at 8-12RE upstream. In addition, in-situ measurements of the magnetic and electric fields, plasma density will be performed by on-board instruments.
In this article, we present an outline of previous missions and designs for magnetospheric studies, along with the science drivers and motivation for the APIS mission. Furthermore, preliminary design results are included to show the feasibility of such a mission. The science requirements drive the APIS mission design, the mission operation and the system requirements. In addition to the various science payloads, critical subsystems of the satellites are investigated e.g., navigation, communication, processing and power systems. We summarize our findings, along with the potential next steps to strengthen our design study.

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R. Rajan, S. Ben-Maor, S. Kaderali, et. al.
Tue, 6 Jul 21
43/74

Comments: Accepted in Acta Astronautica

A Hybrid Genetic-Fuzzy Controller for a 14-inches Astronomical Telescope Tracking [CL]

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http://arxiv.org/abs/2106.12075


The performance of on telescope depend strongly on its operating conditions. During pointing the telescope can move at a relatively high velocity, and the system can tolerate trajectory position errors higher than during tracking. On the contrary, during tracking Alt-Az telescopes generally move slower but still in a large dynamic range. In this case, the position errors must be as close to zero as possible. Tracking is one of the essential factors that affect the quality of astronomical observations. In this paper, a hybrid Genetic-Fuzzy approach to control the movement of a two-link direct-drive Celestron telescope is introduced. The proposed controller uses the Genetic algorithm (GA) for optimizing a fuzzy logic controller (FLC) to improve the tracking of the 14-inches Celestron telescope of the Kottamia Astronomical Observatory (KAO). The fuzzy logic input is a vector of the position error and its rate of change, and the output is torque. The GA objective function used here is the Integral Time Absolute Error (ITAE). The proposed method is compared with a conventional Proportional-Differential (PD) controller, an optimized PD controller with a GA, and a Fuzzy controller. The results show the effectiveness of the proposed controller to improve the dynamic response of the overall system.

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D. Eid, A. Attia, S. Elmasry, et. al.
Thu, 24 Jun 21
11/54

Comments: 10 pages, 3 tables, 9 figures, accepted for publication in Journal of Astronomical Instrumentation (JAI)

Laboratory demonstration of the local oscillator concept for the Event Horizon Imager [IMA]

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http://arxiv.org/abs/2106.12316


Black hole imaging challenges the 3rd generation space VLBI, the Very Long Baseline Interferometry, to operate on a 500 GHz band. The coherent integration timescale needed here is of 450 s though the available space oscillators cannot offer more than 10 s. Self-calibration methods might solve this issue in an interferometer formed by 3 antenna/satellite system, but the need in the 3rd satellite increases mission costs. A frequency transfer is of special interest to alleviate both performance and cost issues. A concept of 2-way optical frequency transfer is examined to investigate its suitability to enable space-to-space interferometry, in particular, to image the ‘shadows’ of black holes from space. The concept, promising on paper, has been demonstrated by tests. The laboratory test set-up is presented and the verification of the temporal stability using standard analysis tool as TimePod is given. The resulting Allan Deviation is dominated by the 1/$\tau$ phase noise trend since the frequency transfer timescale of interest is shorter than 0.2 s. This trend continues into longer integration times, as proven by the longest tests spanning over a few hours. The Allan Deviation between derived 103.2 GHz oscillators is $1.1\times10^{-14}/\tau$ within 10 ms < $\tau$ < 1,000 s that degrades twice towards the longest delay 0.2 s. The worst case satisfies the requirement with a margin of an order of magnitude. The obtained coherence in range of 0.997-0.9998 is beneficial for space VLBI at 557 GHz. The result is of special interest to future science missions for black hole imaging from space.

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V. Kudriashov, M. Martin-Neira, E. Lia, et. al.
Thu, 24 Jun 21
21/54

Comments: 17 pages, 14 figures, accepted by JAI

Real-Time Detection and Classification of Astronomical Transient Events: The State-of-the-Art [IMA]

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http://arxiv.org/abs/2105.00089


In the last years, the need for automated real-time detection and classification of astronomical transients began to be more impelling. Better technologies involve a higher number of detected candidates and an automated classification will allow dealing with this amount of data, every night. The desired state-of-the-art in detection and classification will be presented in its key features and different practical approaches will be introduced, as well. Several ongoing and future surveys will be presented, showing the current situation of Time-Domain Astronomy, and eventually compared with the desired state-of-the-art. The final purpose of this paper is to highlight the general technology readiness level with respect to the level yet to be achieved.

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G. Broccia
Tue, 4 May 21
22/72

Comments: N/A

Development of the first Portuguese radar tracking sensor for Space Debris [CL]

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http://arxiv.org/abs/2102.10457


Currently, space debris represents a threat for satellites and space-based operations, both in-orbit and during the launching process. The yearly increase in space debris represents a serious concern to major space agencies leading to the development of dedicated space programs to deal with this issue. Ground-based radars can detect Earth orbiting debris down to a few square centimeters and therefore constitute a major building block of a space debris monitoring system. New radar sensors are required in Europe to enhance capabilities and availability of its small radar network capable of tracking and surveying space objects and to respond to the debris increase expected from the New Space economy activities. This article presents ATLAS, a new tracking radar system for debris detection located in Portugal. It starts by an extensive technical description of all the system components followed by a study that estimates its future performance. A section dedicated to waveform design is also presented, since the system allows the usage of several types of pulse modulation schemes such as LFM and phase coded modulations while enabling the development and testing of more advanced ones. By presenting an architecture that is highly modular with fully digital signal processing, ATLAS establishes a platform for fast and easy development, research and innovation. The system follows the use of Commercial-Off-The-Shelf technologies and Open Systems which is unique among current radar systems.

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J. Pandeirada, M. Bergano, J. Neves, et. al.
Tue, 23 Feb 21
6/79

Comments: Reviewed; Accepted for Publication at Signals, MDPI, ISSN 2624-6120, February 2021; 16 pages, 8 Figures

Energy Production in Martian Environment — Powering a Mars Direct-based Habitat [EPA]

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http://arxiv.org/abs/2101.07165


This thesis work aims to study the possibility of energy production on Martian soil and, in particular, to establish what might be an optimal configuration for an energy system. This goal has been contextualized in the will to feed a scientific base, based the concept of “Mars Direct” (Robert Zubrin, 1990). This habitat has been recreated in its thermal features, in order to perform an analysis of the heat loss over a Martian year (1,88 terrestrial years). As part of this analysis, two possible scenarios have been studied: clear sky with medium solar radiation (“sun season”) and sand storm season (“storm season”). Subsequently, a basic life support system have been simulated thanks to Aspen PLUS. Using the results of the thermal analysis, it has been possible to obtain a thermal and electrical demand profile for the Hab. After identifying every possible energy source (solar, wind, nuclear, fuel cells, rtg), a calculation on Excel has been set with the purpose of finding one of the configurations with the lowest possible mass and pave the way for a further, more rigorous, optimization. It is indeed clear that shipping 1 kilogram to Mars has a cost of hundreds of thousand of dollars.

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G. Broccia
Tue, 19 Jan 21
16/92

Comments: Master’s thesis

Planning a Reference Constellation for Radiometric Cross-Calibration of Commercial Earth Observing Sensors [CL]

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http://arxiv.org/abs/2010.09946


The Earth Observation planning community has access to tools that can propagate orbits and compute coverage of Earth observing imagers with customizable shapes and orientation, model the expected Earth Reflectance at various bands, epochs and directions, generate simplified instrument performance metrics for imagers and radars, and schedule single and multiple spacecraft payload operations. We are working toward integrating existing tools to design a planner that allows commercial small spacecraft to assess the opportunities for cross-calibration of their sensors against current satellite to be calibrated, specifications of the reference instruments, sensor stability, allowable latency between calibration measurements, differences in viewing and solar geometry between calibration measurements, etc. The planner would output cross-calibration opportunities for every reference target pair as a function of flexible user-defined parameters. We use a preliminary version of this planner to inform the design of a constellation of transfer radiometers that can serve as stable, radiometric references for commercial sensors to cross-calibrate with. We propose such a constellation for either vicarious cross-calibration using pre-selected sites, or top of the atmosphere (TOA) cross-calibration globally. Results from the calibration planner applied to a subset of informed architecture designs show that a 4 sat constellation provides multiple calibration opportunities within half a day planning horizon, for Cubesat sensors deployed into a typical rideshare orbits. While such opportunities are available for cross calibration image pairs within 5 deg of solar or view directions, and with-in an hour (for TOA) and less than a day (vicariously), the planner allows us to identify many more by relaxing user-defined restrictions.

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S. Nag, P. Dabney, V. Ravindra, et. al.
Wed, 21 Oct 20
55/79

Comments: N/A

The Design of a Space-based Observation and Tracking System for Interstellar Objects [IMA]

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http://arxiv.org/abs/2002.00984


The recent observation of interstellar objects, 1I/Oumuamua and 2I/Borisov cross the solar system opened new opportunities for planetary science and planetary defense. As the first confirmed objects originating outside of the solar system, there are myriads of origin questions to explore and discuss, including where they came from, how did they get here and what are they composed of. Besides, there is a need to be cognizant especially if such interstellar objects pass by the Earth of potential dangers of impact. Specifically, in the case of Oumuamua, which was detected after its perihelion, passed by the Earth at around 0.2 AU, with an estimated excess speed of 60 km/s relative to the Earth. Without enough forewarning time, a collision with such high-speed objects can pose a catastrophic danger to all life Earth. Such challenges underscore the importance of detection and exploration systems to study these interstellar visitors. The detection system can include a spacecraft constellation with zenith-pointing telescope spacecraft. After an event is detected, a spacecraft swarm can be deployed from Earth to flyby past the visitor. The flyby can then be designed to perform a proximity operation of interest. This work aims to develop algorithms to design these swarm missions through the IDEAS (Integrated Design Engineering & Automation of Swarms) architecture. Specifically, we develop automated algorithms to design an Earth-based detection constellation and a spacecraft swarm that generates detailed surface maps of the visitor during the rendezvous, along with their heliocentric cruise trajectories.

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R. Nallapu, Y. Xu, A. Marquez, et. al.
Wed, 5 Feb 20
52/67

Comments: 19 pages, 17 figures, AAS GNC Conferences 2020/Advances in Astronautical Sciences

Gyro-Control of a Solar Sailing Satellite [CL]

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http://arxiv.org/abs/1910.13841


Recent successes in the deployment of sails in space have reduced the risk associated with solar sailing missions. The attitude control requirements for a solar sailing mission is low with only slow attitude maneuvers needed to maintain a stable attitude and produce a required solar thrust. Future science missions will require large attitude maneuvers with a fully deployed sail. This article investigates the current options for attitude control on solar sails and proposes a gyro-controlled solar sailing. This concept uses a spinning solar sail to construct a control moment gyroscope capable to produce large torques. Steering laws for performing attitude maneuvers and simulation results are presented which demonstrates the capabilities of such a solution.

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H. Jordaan and W. Steyn
Thu, 31 Oct 19
46/55

Comments: N/A

Towards End-To-End Design of Spacecraft Swarms for Small-Body Reconnaissance [IMA]

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http://arxiv.org/abs/1910.03828


The exploration of small bodies in the Solar System is a high priority planetary science. Asteroids, comets, and planetary moons yield important information about the evolution of the Solar System. Additionally, they could provide resources for a future space economy. While much research has gone into exploring asteroids and comets, dedicated spacecraft missions to planetary moons are few and far between. There are three fundamental challenges of a spacecraft mission to the planetary moons: The first challenge is that the spheres of influence of most moons (except that of Earth) are small and, in many cases, virtually absent. The second is that many moons are tidally locked to their planets, which means that an observer on the planet will have an entire hemisphere, which is always inaccessible. The third challenge is that at a given time about half of the region will be in the Sun’s shadow. Therefore, a single spacecraft mission to observe the planetary moon cannot provide complete coverage. Such a complex task can be solved using a swarm approach, where the mapping task is delegated to multiple low-cost spacecraft. Clearly, the design of a swarm mission for such a dynamic environment is challenging. For this reason, we have proposed the Integrated Design Engineering & Automation of Swarms (IDEAS) software to perform automated end-to-end design of swarm missions. Specifically, it will use a sub-module known as the Automated Swarm Designer module to find optimal swarm configurations suited for a given mission. In our previous work, we have developed the Automated Swarm Design module to find swarm configurations for asteroid mapping operations. In this work, we will evaluate the capability of the Automated Swarm module to design missions to planetary moons.

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R. Nallapu and J. Thangavelautham
Thu, 10 Oct 19
29/63

Comments: 12 pages, 13 figures, International Astronautical Congress 2019

Line-of-Sight Deep-Space Autonomous Navigation [CL]

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http://arxiv.org/abs/1909.08459


Autonomous navigation is one of the main enabling technologies for future space missions. While conventional spacecraft are navigated through ground stations, their employment for deep-space CubeSats yields costs comparable to those of the platform. This paper introduces an extended Kalman filter formulation for spacecraft navigation exploiting the line-of-sight observations of visible Solar System objects to infer the spacecraft state. The line-of-sight error budget builds upon typical performances of deep-space CubeSats and includes uncertainties deriving from the platform attitude, the image processing, and the performances of the sensors. The errors due to the low-thrust propagation and light-time delays to the navigation beacons are also taken into account. Preliminary results show the feasibility of the deep-space autonomous navigation exploiting the line-of-sight directions to visible beacons with a 3-sigma accuracy of 1000km for the position components and 2 m/s for the velocity components.

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V. Franzese and F. Topputo
Thu, 19 Sep 19
56/71

Comments: N/A

Seeker based Adaptive Guidance via Reinforcement Meta-Learning Applied to Asteroid Close Proximity Operations [CL]

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http://arxiv.org/abs/1907.06098


Current practice for asteroid close proximity maneuvers requires extremely accurate characterization of the environmental dynamics and precise spacecraft positioning prior to the maneuver. This creates a delay of several months between the spacecraft’s arrival and the ability to safely complete close proximity maneuvers. In this work we develop an adaptive integrated guidance, navigation, and control system that can complete these maneuvers in environments with unknown dynamics, with initial conditions spanning a large deployment region, and without a shape model of the asteroid. The system is implemented as a policy optimized using reinforcement meta-learning. The spacecraft is equipped with an optical seeker that locks to either a terrain feature, back-scattered light from a targeting laser, or an active beacon, and the policy maps observations consisting of seeker angles and LIDAR range readings directly to engine thrust commands. The policy implements a recurrent network layer that allows the deployed policy to adapt real time to both environmental forces acting on the agent and internal disturbances such as actuator failure and center of mass variation. We validate the guidance system through simulated landing maneuvers in a six degrees-of-freedom simulator. The simulator randomizes the asteroid’s characteristics such as solar radiation pressure, density, spin rate, and nutation angle, requiring the guidance and control system to adapt to the environment. We also demonstrate robustness to actuator failure, sensor bias, and changes in the spacecraft’s center of mass and inertia tensor. Finally, we suggest a concept of operations for asteroid close proximity maneuvers that is compatible with the guidance system.

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B. Gaudet, R. Linares and R. Furfaro
Tue, 16 Jul 19
85/89

Comments: Accepted for 2020 AAS Conference

A framework to monitor activities of satellite data processing in real-time [IMA]

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http://arxiv.org/abs/1812.02234


Space Monitoring Data Center (SMDC) of SINP MSU is one of the several centers in the world that collects data on the radiational conditions in near-Earth orbit from various Russian (Lomonosov, Electro-L1, Electro-L2, Meteor-M1, Meteor-M2, etc.) and foreign (GOES 13, GOES 15, ACE, SDO, etc.) satellites. The primary purposes of SMDC are: aggregating heterogeneous data from different sources; providing a unified interface for data retrieval, visualization, analysis, as well as development and testing new space weather models; and controlling the correctness and completeness of data. Space weather models rely on data provided by SMDC to produce forecasts. Therefore, monitoring the whole data processing cycle is crucial for further success in the modelling of physical processes in near-Earth orbit based on the collected data. To solve the problem described above, we have developed a framework called Live Monitor at SMDC. Live Monitor allows watching all stages and program components involved in each data processing cycle. All activities of each stage are logged by Live Monitor and shown in real-time on a web interface. When an error occurs, a notification message will be sent to satellite operators via email and the Telegram messenger service so that they could take measures in time. The Live Monitor’s API can be used to create a customized monitoring service with minimum coding.

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M. Nguyen and A. Kryukov
Fri, 7 Dec 18
1/66

Comments: 6 pages, 3 figures, International Conference on Computer Simulation in Physics and beyond October 9-12, 2017, Moscow, Russia

Constrained Least Squares for Extended Complex Factor Analysis [CL]

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http://arxiv.org/abs/1804.00430


For subspace estimation with an unknown colored noise, Factor Analysis (FA) is a good candidate for replacing the popular eigenvalue decomposition (EVD). Finding the unknowns in factor analysis can be done by solving a non-linear least square problem. For this type of optimization problems, the Gauss-Newton (GN) algorithm is a powerful and simple method. The most expensive part of the GN algorithm is finding the direction of descent by solving a system of equations at each iteration. In this paper we show that for FA, the matrices involved in solving these systems of equations can be diagonalized in a closed form fashion and the solution can be found in a computationally efficient way. We show how the unknown parameters can be updated without actually constructing these matrices. The convergence performance of the algorithm is studied via numerical simulations.

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A. Sardarabadi, A. Veen and L. Koopmans
Tue, 3 Apr 18
48/57

Comments: N/A

Improving science yield for NASA Swift with automated planning technologies [IMA]

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http://arxiv.org/abs/1712.08111


The Swift Gamma-Ray Burst Explorer is a uniquely capable mission, with three on-board instruments and rapid slewing capabilities. It serves as a fast-response satellite observatory for everything from gravitational-wave counterpart searches to cometary science. Swift averages 125 different observations per day, and is consistently over-subscribed, responding to about one-hundred Target of Oportunity (ToO) requests per month from the general astrophysics community, as well as co-pointing and follow-up agreements with many other observatories. Since launch in 2004, the demands put on the spacecraft have grown consistently in terms of number and type of targets as well as schedule complexity. To facilitate this growth, various scheduling tools and helper technologies have been built by the Swift team to continue improving the scientific yield of the Swift mission. However, these tools have been used only to assist humans in exploring the local pareto surface and for fixing constraint violations. Because of the computational complexity of the scheduling task, no automation tool has been able to produce a plan of equal or higher quality than that produced by a well-trained human, given the necessary time constraints. In this proceeding we formalize the Swift Scheduling Problem as a dynamic fuzzy Constraint Satisfaction Problem (DF-CSP) and explore the global solution space. We detail here several approaches towards achieving the goal of surpassing human quality schedules using classical optimization and algorithmic techniques, as well as machine learning and recurrent neural network (RNN) methods. We then briefly discuss the increased scientific yield and benefit to the wider astrophysics community that would result from the further development and adoption of these technologies.

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A. Tohuvavohu
Fri, 22 Dec 17
20/52

Comments: 5 pages, 1 figure. Submitted for the proceedings of the 18th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 2017)

Control of a Bucket-Wheel for Surface Mining of Asteroids and Small-Bodies [CL]

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http://arxiv.org/abs/1702.00335


Near Earth Asteroids (NEAs) are thought to contain a wealth of resources, including water, iron, titanium, nickel, platinum and silicates. Future space missions that can exploit these resources by performing In-Situ Resource Utilization (ISRU) gain substantial benefit in terms of range, payload capacity and mission flexibility. Compared to the Moon or Mars, the milligravity on some asteroids demands a fraction of the energy for digging and accessing hydrated regolith just below the surface. However, asteroids and small-bodies, because of their low gravity present a major challenge in landing, surface excavation and resource capture. These challenges have resulted in adoption of a “touch and go techniques”, like the upcoming Osiris-rex sample-return mission. Previous asteroid excavation efforts have focused on discrete capture events (an extension of sampling technology) or whole-asteroid capture and processing. This paper analyzes the control of a bucket-wheel design for asteroid or small-body excavation. Our study focuses on system design of two counter rotating bucket-wheels that are attached to a hovering spacecraft. Regolith is excavated and heated to 1000 C to extract water. The water in turn is electrolyzed to produce hydrogen and oxygen for rocket fuel. We analyze control techniques to maximize traction of the bucket-wheels on the asteroid surface and minimize lift-off the surface, together with methods to dig deeper into the asteroid surface. Our studies combine analytical models, with simulation and hardware testing. For initial evaluation of material-spacecraft dynamics and mechanics, we assume lunar-like regolith for bulk density, particle size and cohesion. Our early studies point towards a promising pathway towards refinement of this technology for demonstration aboard a future space mission.

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R. Nallapu, E. Asphaug and J. Thangavelautham
Thu, 2 Feb 17
9/52

Comments: 8 pages, 7 figures in 40th AAS Conference on Guidance, Navigation and Control

Combined Thermal Control and GNC: An Enabling Technology for CubeSat Surface Probes and Small Robots [CL]

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http://arxiv.org/abs/1701.09076


Advances in GNC, particularly from miniaturized control electronics, reaction-wheels and attitude determination sensors make it possible to design surface probes and small robots to perform surface exploration and science on low-gravity environments. These robots would use their reaction wheels to roll, hop and tumble over rugged surfaces. These robots could provide ‘Google Streetview’ quality images of off-world surfaces and perform some unique science using penetrometers. These systems can be powered by high-efficiency fuel cells that operate at 60-65 % and utilize hydrogen and oxygen electrolyzed from water. However, one of the major challenges that prevent these probes and robots from performing long duration surface exploration and science is thermal design and control. In the inner solar system, during the day time, there is often enough solar-insolation to keep these robots warm and power these devices, but during eclipse the temperatures falls well below storage temperature. We have developed a thermal control system that utilizes chemicals to store and dispense heat when needed. The system takes waste products, such as water from these robots and transfers them to a thermochemical storage system. These thermochemical storage systems when mixed with water (a waste product from a PEM fuel cell) releases heat. Under eclipse, the heat from the thermochemical storage system is released to keep the probe warm enough to survive. In sunlight, solar photovoltaics are used to electrolyze the water and reheat the thermochemical storage system to release the water. Our research has showed thermochemical storage systems are a feasible solution for use on surface probes and robots for applications on the Moon, Mars and asteroids.

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S. Rabade and J. Thangavelautham
Wed, 1 Feb 17
24/67

Comments: 12 pages, 15 figures in Proceedings of the 40th Annual AAS Guidance, Navigation and Control Conference 2017

Attitude Control of the Asteroid Origins Satellite 1 (AOSAT 1) [CL]

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http://arxiv.org/abs/1701.09094


Exploration of asteroids and small-bodies can provide valuable insight into the origins of the solar system, into the origins of Earth and the origins of the building blocks of life. However, the low-gravity and unknown surface conditions of asteroids presents a daunting challenge for surface exploration, manipulation and for resource processing. This has resulted in the loss of several landers or shortened missions. Fundamental studies are required to obtain better readings of the material surface properties and physical models of these small bodies. The Asteroid Origins Satellite 1 (AOSAT 1) is a CubeSat centrifuge laboratory that spins at up to 4 rpm to simulate the milligravity conditions of sub 1 km asteroids. Such a laboratory will help to de-risk development and testing of landing and resource processing technology for asteroids. Inside the laboratory are crushed meteorites, the remains of asteroids. The laboratory is equipped with cameras and actuators to perform a series of science experiments to better understand material properties and asteroid surface physics. These results will help to improve our physics models of asteroids. The CubeSat has been designed to be low-cost and contains 3-axis magnetorquers and a single reaction-wheel to induce spin. In our work, we first analyze how the attitude control system will de-tumble the spacecraft after deployment. Further analysis has been conducted to analyze the impact and stability of the attitude control system to shifting mass (crushed meteorites) inside the spacecraft as its spinning in its centrifuge mode. AOSAT 1 will be the first in a series of low-cost CubeSat centrifuges that will be launched setting the stage for a larger, permanent, on-orbit centrifuge laboratory for experiments in planetary science, life sciences and manufacturing.

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R. Nallapu, S. Shah, E. Asphaug, et. al.
Wed, 1 Feb 17
41/67

Comments: 12 pages, 8 figures in Proceedings of the 40th Annual AAS Guidance, Navigation and Control Conference 2017

Automated Design of CubeSats and Small Spacecrafts [CL]

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http://arxiv.org/abs/1701.01742


The miniaturization of electronics, sensors and actuators has enabled the growing use of CubeSats and sub-20 kg spacecraft. Their reduced mass and volume has the potential to translate into significant reductions in required propellant and launch mass for interplanetary missions, earth observation and for astrophysics applications. There is an important need to optimize the design of these spacecraft to better ascertain their maximal capabilities by finding optimized solution, where mass, volume and power is a premium. Current spacecraft design methods require a team of experts, who use their engineering experience and judgement to develop a spacecraft design. Such an approach can miss innovative designs not thought of by a human design team. In this work we present a compelling alternative approach that extends the capabilities of a spacecraft engineering design team to search for and identify near-optimal solutions using machine learning. The approach enables automated design of a spacecraft that requires specifying quantitative goals, requiring reaching a target location or operating at a predetermined orbit for a required time. Next a virtual warehouse of components is specified that be selected to produce a candidate design. Candidate designs are produced using an artificial Darwinian approach, where fittest design survives and reproduce, while unfit individuals are culled off. Our past work in space robotic has produced systems designs and controllers that are human competitive. Finding a near-optimal solution presents vast improvements over a solution obtained through engineering judgment and point design alone. The approach shows a credible pathway to identify and evaluate many more candidate designs than it would be otherwise possible with a human design team alone.

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H. Kalita and J. Thangavelautham
Tue, 10 Jan 17
10/75

Comments: 6 pages, 11 figures, Proceedings of the International Astronautical Congress, 2016

An In Situ Measurement System for Characterizing Orbital Debris [CL]

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http://arxiv.org/abs/1612.03971


This paper presents the development of an in situ measurement system known as the Debris Resistive Acoustic Grid Orbital Navy/NASA Sensor (DRAGONS). The DRAGONS system is designed to detect impacts caused by particles ranging from 50 micrometers to 1 mm at both low-earth and geostationary orbits. DRAGONS utilizes a combination of low-cost sensor technologies to facilitate accurate measurements and approximations of the size, velocity, and angle of impacting micrometeoroids and orbital debris (MMOD). Two thin layers of kapton sheets with resistive traces are used to detect the changes in resistance that are directly proportional to the impacting force caused by the fast traveling particles. Four polyvinylidene fluoride-based sensors are positioned in the back of each kapton sheet to measure acoustic strain caused by an impact. The electronic hardware module that controls all operations employs a low-power, modular, and compact design that enables it to be installed as a low-resource load on a host satellite. Laboratory results demonstrate that in addition to having the ability to detect an impact event, the DRAGONS system can determine impact location, speed, and angle of impact with a mean error of 1.4 cm, 0.2 km/s, and 5{\deg}. The DRAGONS system could be deployed as an add-on subsystem of a payload to enable a real-time, in-depth study of the properties of MMOD.

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M. Tsao, H. Ngo, R. Corsaro, et. al.
Wed, 14 Dec 16
5/67

Comments: 15 pages

GTOC8: Results and Methods of ESA Advanced Concepts Team and JAXA-ISAS [CL]

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http://arxiv.org/abs/1602.00849


We consider the interplanetary trajectory design problem posed by the 8th edition of the Global Trajectory Optimization Competition and present the end-to-end strategy developed by the team ACT-ISAS (a collaboration between the European Space Agency’s Advanced Concepts Team and JAXA’s Institute of Space and Astronautical Science). The resulting interplanetary trajectory won 1st place in the competition, achieving a final mission value of $J=146.33$ [Mkm]. Several new algorithms were developed in this context but have an interest that go beyond the particular problem considered, thus, they are discussed in some detail. These include the Moon-targeting technique, allowing one to target a Moon encounter from a low Earth orbit; the 1-$k$ and 2-$k$ fly-by targeting techniques, enabling one to design resonant fly-bys while ensuring a targeted future formation plane% is acquired at some point after the manoeuvre ; the distributed low-thrust targeting technique, admitting one to control the spacecraft formation plane at 1,000,000 [km]; and the low-thrust optimization technique, permitting one to enforce the formation plane’s orientations as path constraints.

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D. Izzo, D. Hennes, M. Martens, et. al.
Wed, 3 Feb 16
49/54

Comments: Presented at the 26th AAS/AIAA Space Flight Mechanics Meeting, Napa, CA