Tag Archives: Robotics

Quasi Real-Time Autonomous Satellite Detection and Orbit Estimation [IMA]

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http://arxiv.org/abs/2304.06227


A method of near real-time detection and tracking of resident space objects (RSOs) using a convolutional neural network (CNN) and linear quadratic estimator (LQE) is proposed. Advances in machine learning architecture allow the use of low-power/cost embedded devices to perform complex classification tasks. In order to reduce the costs of tracking systems, a low-cost embedded device will be used to run a CNN detection model for RSOs in unresolved images captured by a gray-scale camera and small telescope. Detection results computed in near real-time are then passed to an LQE to compute tracking updates for the telescope mount, resulting in a fully autonomous method of optical RSO detection and tracking. Keywords: Space Domain Awareness, Neural Networks, Real-Time, Object Detection, Embedded Systems.

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J. Jordan, D. Posada, M. Gillette, et. al.
Fri, 14 Apr 23
25/64

Comments: SPIE Defense and Commercial 2023, Orlando, FL

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

Supervisory Coordination of Robotic Fiber Positioners in Multi-Object Spectrographs [IMA]

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http://arxiv.org/abs/2210.05013


In this paper, we solve the complete coordination problem of robotic fiber positioners using supervisory control theory. In particular, we model positioners and their behavioral specifications as discrete-event systems by the discretization of their motion spaces. We synthesize a coordination supervisor associated with a specific set of positioners. In particular, the coordination supervisor includes the solutions to the complete coordination problem of its corresponding positioners. Then, we use the backtracking forcibility technique of supervisory control theory to present an algorithm based on a completeness condition to solve the coordination problem similar to a reconfiguration problem. We illustrate the functionality of our method using an example.

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M. Macktoobian, D. Gillet and J. Kneib
Wed, 12 Oct 22
29/75

Comments: N/A

Astrobotics: Swarm Robotics for Astrophysical Studies [IMA]

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http://arxiv.org/abs/2210.02587


This paper introduces the emerging field of astrobotics, that is, a recently-established branch of robotics to be of service to astrophysics and observational astronomy. We first describe a modern requirement of dark matter studies, i.e., the generation of the map of the observable universe, using astrobots. Astrobots differ from conventional two-degree-of-freedom robotic manipulators in two respects. First, the dense formation of astrobots give rise to the extremely overlapping dynamics of neighboring astrobots which make them severely subject to collisions. Second, the structure of astrobots and their mechanical specifications are specialized due to the embedded optical fibers passed through them. We focus on the coordination problem of astrobots whose solutions shall be collision-free, fast execution, and complete in terms of the astrobots’ convergence rates. We also illustrate the significant impact of astrobots assignments to observational targets on the quality of coordination solutions To present the current state of the field, we elaborate the open problems including next-generation astrophysical projects including 20,000 astrobots, and other fields, such as space debris tracking, in which astrobots may be potentially used

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M. Macktoobian, D. Gillet and J. Kneib
Fri, 7 Oct 22
18/62

Comments: N/A

Learning convergence prediction of astrobots in multi-object spectrographs [IMA]

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http://arxiv.org/abs/2210.02600


Astrobot swarms are used to capture astronomical signals to generate the map of the observable universe for the purpose of dark energy studies. The convergence of each swarm in the course of its coordination has to surpass a particular threshold to yield a satisfactory map. The current coordination methods do not always reach desired convergence rates. Moreover, these methods are so complicated that one cannot formally verify their results without resource-demanding simulations. Thus, we use support vector machines to train a model which can predict the convergence of a swarm based on the data of previous coordination of that swarm. Given a fixed parity, i.e., the rotation direction of the outer arm of an astrobot, corresponding to a swarm, our algorithm reaches a better predictive performance compared to the state of the art. Additionally, we revise our algorithm to solve a more generalized convergence prediction problem according to which the parities of astrobots may differ. We present the prediction results of a generalized scenario, associated with a 487-astrobot swarm, which are interestingly efficient and collision-free given the excessive complexity of this scenario compared to the constrained one.

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M. Macktoobian, F. Basciani, D. Gillet, et. al.
Fri, 7 Oct 22
21/62

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

Design of Low Thrust Controlled Maneuvers to Chase and De-orbit the Space Debris [CL]

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http://arxiv.org/abs/2204.00674


Over the several decades, the space debris at LEO has grown rapidly which had caused a serious threat to the operating satellite in an orbit. To avoid the risk of collision and protect the LEO environment, the space robotics ADR concept has been continuously developed for over a decade to chase, capture, and deorbit space debris. This paper presents the designed small satellite with dual robotic manipulators. The small satellite is designed based on CubeSat standards, which uses commercially available products in the market. In this paper, an approach is detailed for designing the controlled chase and deorbit maneuver for a small satellite equipped with an RCS thruster. The maneuvers are comprised of two phases, a. bringing the chaser satellite to the debris orbit and accelerating it to close proximity of 1m to the debris object by using the low thrust RCS thruster, and b. Once captured, controlled deorbiting it to 250 km of altitude. A Hohmann transfer concept is used to move our chaser satellite from the lower orbit to the debris orbit by two impulsive burns. A number of the scenarios are simulated, where one or more orbital elements are adjusted. For more than one orbital elements adjustment, the DAG law and the Q law are utilized. These laws synthesize the three direction thrusts to the single thrust force for the controlled maneuver. The $\Delta$V requirement at each maneuver is determined by using the performance parameters of the RCS thruster intended for a small satellite. The results show that, for long term simulation of a chaser satellite maneuver to debris object, an optimum DAG law is most suitable than the Q law, as it can handle the singularity behavior of the orbital elements caused due by adjustment of one or more elements more efficiently.

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R. Sah, R. Srivastava and K. Das
Tue, 5 Apr 22
81/83

Comments: 23 Pages, 21 Figures, Presented & Published at ASET 2022 Conference on “Artificial Intelligence(AI) Enabled Aerobots and Hydrobots” Organized by ISRO Inertial Systems Unit & IIST at Vikram Sarabhai Space Center, Thiruvananthapuram, India on 17-18, March, 2022, this https URL

Gravity Estimation at Small Bodies via Optical Tracking of Hopping Artificial Probes [IMA]

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http://arxiv.org/abs/2202.06412


Despite numerous successful missions to small celestial bodies, the gravity field of such targets has been poorly characterized so far. Gravity estimates can be used to infer the internal structure and composition of small bodies and, as such, have strong implications in the fields of planetary science, planetary defense, and in-situ resource utilization. Current gravimetry techniques at small bodies mostly rely on tracking the spacecraft orbital motion, where the gravity observability is low. To date, only lower-degree and order spherical harmonics of small-body gravity fields could be resolved. In this paper, we evaluate gravimetry performance for a novel mission architecture where artificial probes repeatedly hop across the surface of the small body and perform low-altitude, suborbital arcs. Such probes are tracked using optical measurements from the mothership’s onboard camera and orbit determination is performed to estimate the probe trajectories, the small body’s rotational kinematics, and the gravity field. The suborbital motion of the probes provides dense observations at low altitude, where the gravity signal is stronger. We assess the impact of observation parameters and mission duration on gravity observability. Results suggest that the gravitational spherical harmonics of a small body with the same mass as the asteroid Bennu, can be observed at least up to degree 40 within months of observations. Measurement precision and frequency are key to achieve high-performance gravimetry.

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J. Villa, A. French, J. McMahon, et. al.
Tue, 15 Feb 22
9/75

Comments: Originally presented at 2021 AAS Astrodynamics Specialist Conference

Feasible Low-thrust Trajectory Identification via a Deep Neural Network Classifier [CL]

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http://arxiv.org/abs/2202.04962


In recent years, deep learning techniques have been introduced into the field of trajectory optimization to improve convergence and speed. Training such models requires large trajectory datasets. However, the convergence of low thrust (LT) optimizations is unpredictable before the optimization process ends. For randomly initialized low thrust transfer data generation, most of the computation power will be wasted on optimizing infeasible low thrust transfers, which leads to an inefficient data generation process. This work proposes a deep neural network (DNN) classifier to accurately identify feasible LT transfer prior to the optimization process. The DNN-classifier achieves an overall accuracy of 97.9%, which has the best performance among the tested algorithms. The accurate low-thrust trajectory feasibility identification can avoid optimization on undesired samples, so that the majority of the optimized samples are LT trajectories that converge. This technique enables efficient dataset generation for different mission scenarios with different spacecraft configurations.

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R. Xie and A. Dempster
Fri, 11 Feb 22
32/71

Comments: 18 Pages; 10 figures; Presented at 2021 AAS/AIAA Astrodynamics Specialist Conference, Big Sky, Virtual

GNC Analysis and Robotic Systems Configuration of Collision-free Earth Observation Satellites (CfEOS) Constellations [IMA]

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http://arxiv.org/abs/2110.11387


The high number of objects in the LEO is a risk that collisions between sub-orbital or escape velocity objects with an orbiting object of satellites occur when two satellites collide while orbiting the earth. One of the approaches to avoid collisions is a robotic configuration of satellite constellations. Satellite constellations should not be confused with satellite clusters, which are groups of satellites moving in close proximity to each other in nearly identical orbits; nor with satellite series or satellite programs, which are generations of satellites launched successively; nor with satellite fleets, which are groups of satellites from the same manufacturer or operator that operate an independent system. CfEOS constellations designed for geospatial applications and Earth observation. Unlike a single satellite, a constellation can provide permanent global or near-global coverage anywhere on Earth. CfEOS constellations are configured in sets of complementary orbital planes and connect to ground stations located around the globe. This paper describes the GNC analysis, the orbit propagation and robotic systems configuration for Collision-free Earth observation satellites (CfEOS) constellations.

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M. Ntumba, S. Gore, P. Jain, et. al.
Mon, 25 Oct 21
11/76

Comments: 9 pages, 1 table, 8 figures

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

Experimental evaluation of complete safe coordination of astrobots for Sloan Digital Sky Survey V [IMA]

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http://arxiv.org/abs/2012.10656


The data throughput of massive spectroscopic surveys in the course of each observation is directly coordinated with the number of optical fibers which reach their target. In this paper, we evaluate the safety and the performance of the astrobots coordination in SDSS-V by conducting various experimental and simulated tests. We illustrate that our strategy provides a complete coordination condition which depends on the operational characteristics of astrobots, their configurations, and their targets. Namely, a coordination method based on the notion of cooperative artificial potential fields is used to generate safe and complete trajectories for astrobots. Optimal target assignment further improves the performance of the used algorithm in terms of faster convergences and less oscillatory movements. Both random targets and galaxy catalog targets are employed to observe the coordination success of the algorithm in various target distributions. The proposed method is capable of handling all potential collisions in the course of coordination. Once the completeness condition is fulfilled according to initial configuration of astrobots and their targets, the algorithm reaches full convergence of astrobots. Should one assign targets to astrobots using efficient strategies, convergence time as well as the number of oscillations decrease in the course of coordination. Rare incomplete scenarios are simply resolved by trivial modifications of astrobots swarms’ parameters.

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M. Macktoobian, R. Araújo, L. Grossen, et. al.
Tue, 22 Dec 20
1/89

Comments: this https URL

Development of Techniques Enabling Suborbital Small Object Capture Around Low Gravity Asteroids [IMA]

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http://arxiv.org/abs/2012.10329


The exploration of small body asteroids provides direct access to the primitive building blocks of our solar system. Sample and return missions enable chemical and radioisotope studies which not only provide evidence for the formation of the solar system, but also a basic understanding of where resources might be found for future exploitation. The touch-down and sample techniques established by Hayabusa-2 and OSIRIS-REx accomplish this mission by physically touching down on the asteroid and collecting samples into a basket extended via a probe from the bottom of the spacecraft. This technique has been demonstrated to work, but contains a high cost in both mission operations as well as the size and complexity of the collection mechanism itself. This paper explores an alternative sample and return technique by exploiting the recent discovery of regolith particle ejections from Bennu. Particles ejected from the surface of Bennu are typically 1 cm in size and spend several hours in flight, suggesting the possibility that nanospacecraft deployed from the mother-spacecraft could chase down, collect and return with the sample with minimal sensor and delta-V capability. Key aspects of this mission are developed to reduce risk, and an overall mission concept is developed to establish plausibility.

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L. Vance and J. Thangavelautham
Mon, 21 Dec 20
69/75

Comments: 15 pages, 12 figures, Accepted to AIAA SciTech 2021

FemtoSats for Exploring Permanently Shadowed Regions on the Moon [IMA]

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http://arxiv.org/abs/2012.08651


The recent, rapid advancement in space exploration is thanks to the accelerated miniaturization of electronics components on a spacecraft that is reducing the mass, volume and cost of satellites. Yet, access to space remains a distant dream as there is growing complexity in what is required of satellites and increasing space traffic. Interplanetary exploration is even harder and has limited possibilities for low cost mission. All of these factors make even CubeSats, the entry-level standard too expensive for most and therefore a better way needs to be found. The proposed solution in this report is a low-mass, low-cost, disposable solution that exploits the latest advances in electronics and is relatively easy to integrate: FemtoSats. FemtoSats are sub-100-gram spacecraft. The FemtoSat concept is based on launching a swarm where the main tasks are divided between the members of the swarm. This means that if one fails the swarm can take its place and therefore substitute it without risking the whole mission. In this paper we explore the utility of FemtoSats to perform first exploration and mapping of a Lunar PSR. This concept was recognized as finalist for the NASA BIG Competition in 2020. This is an example of a high-risk, high-reward mission where losing one FemtoSat does not mean the mission is in danger as it happens with regular satellite missions.

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A. Diaz-Flores, J. Fernández, L. Vance, et. al.
Thu, 17 Dec 20
30/85

Comments: 10 pages, 8 figures, accepted to IEEE Aerospace Conference 2021

SDSS-V Algorithms: Fast, Collision-Free Trajectory Planning for Heavily Overlapping Robotic Fiber Positioners [CL]

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http://arxiv.org/abs/2012.04721


Robotic fiber positioner (RFP) arrays are becoming heavily adopted in wide field massively multiplexed spectroscopic survey instruments. RFP arrays decrease nightly operational overheads through rapid reconfiguration between fields and exposures. In comparison to similar instruments, SDSS-V has selected a very dense RFP packing scheme where any point in a field is typically accessible to three or more robots. This design provides flexibility in target assignment. However, the task of collision-less trajectory planning is especially challenging. We present two multi-agent distributed control strategies that are highly efficient and computationally inexpensive for determining collision-free paths for RFPs in heavily overlapping workspaces. We demonstrate that a reconfiguration path between two arbitrary robot configurations can be efficiently found if “folded” state, in which all robot arms are retracted and aligned in a lattice-like orientation, is inserted between the initial and final states. Although developed for SDSS-V, the approach we describe is generic and so applicable to a wide range of RFP designs and layouts. Robotic fiber positioner technology continues to advance rapidly, and in the near future ultra-densely packed RFP designs may be feasible. Our algorithms are especially capable in routing paths in very crowded environments, where we see efficient results even in regimes significantly more crowded than the SDSS-V RFP design.

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C. Sayres, J. Sánchez-Gallego, M. Blanton, et. al.
Thu, 10 Dec 20
15/87

Comments: To be published in the Astronomical Journal

Introducing MISS, a new tool for collision avoidance analysis and design [IMA]

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http://arxiv.org/abs/2010.08379


The core aspects and latest developments of Manoeuvre Intelligence for Space Safety (MISS), a new software tool for collision avoidance analysis and design, are presented. The tool leverages analytical and semi-analytical methods for the efficient modelling of the orbit modifications due to different control strategies, such as impulsive or low-thrust manoeuvres, and maps them into displacements at the nominal close approach using relative motion equations. B-plane representations are then used to separate the phasing-related and geometry-related components of the displacement. Both maximum miss distance and minimum collision probability collision avoidance manoeuvres are considered. The tool also allows for the computation of state transition matrices and propagation of uncertainties. Several test cases are provided to assess the capabilities and performance of the tool.

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J. Gonzalo, C. Colombo and P. Lizia
Mon, 19 Oct 20
35/44

Comments: 11 pages, 7 figures. Preprint of article published in Journal of Space Safety Engineering

Data-Driven Convergence Prediction of Astrobots Swarms [CL]

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http://arxiv.org/abs/2005.14703


Astrobots are robotic artifacts whose swarms are used in astrophysical studies to generate the map of the observable universe. These swarms have to be coordinated with respect to various desired observations. Such coordination are so complicated that distributed swarm controllers cannot always coordinate enough astrobots to fulfill the minimum data desired to be obtained in the course of observations. Thus, a convergence verification is necessary to check the suitability of a coordination before its execution. However, a formal verification method does not exist for this purpose. In this paper, we instead use machine learning to predict the convergence of astrobots swarm. In particular, we propose a weighted $k$-NN-based algorithm which requires the initial status of a swarm as well as its observational targets to predict its convergence. Our algorithm learns to predict based on the coordination data obtained from previous coordination of the desired swarm. This method first generates a convergence probability for each astrobot based on a distance metric. Then, these probabilities are transformed to either a complete or an incomplete categorical result. The method is applied to two typical swarms including 116 and 487 astrobots. It turns out that the correct prediction of successful coordination may be up to 80% of overall predictions. Thus, these results witness the efficient accuracy of our predictive convergence analysis strategy.

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M. Macktoobian, F. Basciani, D. Gillet, et. al.
Mon, 1 Jun 20
24/50

Comments: N/A

Complete coordination of robotic fiber positioners for massive spectroscopic surveys [IMA]

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http://arxiv.org/abs/2005.10448


Robotic fiber positioners play a vital role in the generation of massive spectroscopic surveys. The more complete a positioners set is coordinated, the more information its corresponding spectrograph receives during an observation. The complete coordination problem of positioners sets is studied in this paper. We first define the local and the global completeness problems and determine their relationship. We then propose a new artificial potential field according to which the convergences of a positioner and its neighboring positioners are cooperatively taken into account. We also discover the required condition for a complete coordination. We finally explain how the modifications of some of the parameters of a positioners set may resolve its incompleteness coordination scenarios. We verify our accomplishments using simulations.

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M. Macktoobian, D. Gillet and J. Kneib
Fri, 22 May 20
15/64

Comments: N/A

Optimal target assignment for massive spectroscopic surveys [IMA]

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http://arxiv.org/abs/2005.08853


Robotics have recently contributed to cosmological spectroscopy to automatically obtain the map of the observable universe using robotic fiber positioners. For this purpose, an assignment algorithm is required to assign each robotic fiber positioner to a target associated with a particular observation. The assignment process directly impacts on the coordination of robotic fiber positioners to reach their assigned targets. In this paper, we establish an optimal target assignment scheme which simultaneously provides the fastest coordination accompanied with the minimum of colliding scenarios between robotic fiber positioners. In particular, we propose a cost function by whose minimization both of the cited requirements are taken into account in the course of a target assignment process. The applied simulations manifest the improvement of convergence rates using our optimal approach. We show that our algorithm scales the solution in quadratic time in the case of full observations. Additionally, the convergence time and the percentage of the colliding scenarios are also decreased in both supervisory and hybrid coordination strategies.

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M. Macktoobian, D. Gillet and J. Kneib
Tue, 19 May 20
92/92

Comments: N/A

Automated Multidisciplinary Design and Control of Hopping Robots for Exploration of Extreme Environments on the Moon and Mars [CL]

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http://arxiv.org/abs/1910.03827


The next frontier in solar system exploration will be missions targeting extreme and rugged environments such as caves, canyons, cliffs and crater rims of the Moon, Mars and icy moons. These environments are time capsules into early formation of the solar system and will provide vital clues of how our early solar system gave way to the current planets and moons. These sites will also provide vital clues to the past and present habitability of these environments. Current landers and rovers are unable to access these areas of high interest due to limitations in precision landing techniques, need for large and sophisticated science instruments and a mission assurance and operations culture where risks are minimized at all costs. Our past work has shown the advantages of using multiple spherical hopping robots called SphereX for exploring these extreme environments. Our previous work was based on performing exploration with a human-designed baseline design of a SphereX robot. However, the design of SphereX is a complex task that involves a large number of design variables and multiple engineering disciplines. In this work we propose to use Automated Multidisciplinary Design and Control Optimization (AMDCO) techniques to find near optimal design solutions in terms of mass, volume, power, and control for SphereX for different mission scenarios.

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H. Kalita and J. Thangavelautham
Thu, 10 Oct 19
34/63

Comments: 11 pages, 13 figures, International Astronautical Congress 2019

Development and Testing of an Engineering Model for an Asteroid Hopping Robot [IMA]

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http://arxiv.org/abs/1910.03831


The science and origins of asteroids is deemed high priority in the Planetary Science Decadal Survey. Two of the main questions from the Decadal Survey pertain to what the “initial stages, conditions, and processes of solar system formation and the nature of the interstellar matter” that was present in the protoplanetary disk, as well as determining the “primordial sources for organic matter.” Major scientific goals for the study of planetesimals are to decipher geological processes in SSSBs not determinable from investigation via in situ experimentation, and to understand how planetesimals contribute to the formation of planets. Ground based observations are not sufficient to examine SSSBs, as they are only able to measure what is on the surface of the body; however, in situ analysis allows for further, close up investigation as to the surface characteristics and the inner composure of the body. The Asteroid Mobile Imager and Geologic Observer (AMIGO) is a 1U stowed autonomous robot that can perform surface hopping on an asteroid with an inflatable structure. It contains science instruments to provide stereo context imaging, micro-imaging, seismic sensing, and electric field measurements. Multiple hopping robots are deployed as a team to eliminate single-point failure and add robustness to data collection. An on-board attitude control system consists of a thruster chip of discretized micro-nozzles that provides hopping thrust and a reaction wheel for controlling the third axis. For the continued development of the robot, an engineering model is developed to test various components and algorithms.

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G. Wilburn, H. Kalita and J. Thangavelautham
Thu, 10 Oct 19
51/63

Comments: 9 pages, 14 figures, International Astronautical Congress 2019. arXiv admin note: text overlap with arXiv:1902.02071“

Building Small-Satellites to Live Through the Kessler Effect [IMA]

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http://arxiv.org/abs/1909.01342


The rapid advancement and miniaturization of spacecraft electronics, sensors, actuators, and power systems have resulted in growing proliferation of small-spacecraft. Coupled with this is the growing number of rocket launches, with left-over debris marking their trail. The space debris problem has also been compounded by test of several satellite killer missiles that have left large remnant debris fields. In this paper, we assume a future in which the Kessler Effect has taken hold and analyze the implications on the design of small-satellites and CubeSats. We use a multiprong approach of surveying the latest technologies, including the ability to sense space debris in orbit, perform obstacle avoidance, have sufficient shielding to take on small impacts and other techniques to mitigate the problem. Detecting and tracking space debris threats on-orbit is expected to be an important approach and we will analyze the latest vision algorithms to perform the detection, followed by quick reaction control systems to perform the avoidance. Alternately there may be scenarios where the debris is too small to track and avoid. In this case, the spacecraft will need passive mitigation measures to survive the impact. Based on these conditions, we develop a strawman design of a small spacecraft to mitigate these challenges. Based upon this study, we identify if there is sufficient present-day COTS technology to mitigate or shield satellites from the problem. We conclude by outlining technology pathways that need to be advanced now to best prepare ourselves for the worst-case eventuality of Kessler Effect taking hold in the upper altitudes of Low Earth Orbit.

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S. Morad, H. Kalita, R. Nallapu, et. al.
Thu, 5 Sep 19
7/87

Comments: 12 pages and 9 figures, accepted to Advanced Maui Optical and Space Surveillance Technologies Conference

Overview of Guidance, Navigation and Control System of the TeamIndus lunar lander [CL]

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http://arxiv.org/abs/1907.10955


TeamIndus’ lunar logistics vision includes multiple lunar missions to meet requirements of science, commercial and efforts towards global exploration. The first mission is slated for launch in 2020. The prime objective is to demonstrate autonomous precision lunar landing, and Surface Exploration Rover to collect data on the vicinity of the landing site. TeamIndus has developed various technologies towards lowering the access barrier to the lunar surface. This paper shall provide an overview of design of lander GNC system. The design of the GNC system has been described after concluding studies on sensor and actuator configurations. Frugal design approach is followed in the selection of GNC hardware. The paper describes the constraints for the orbital maneuvers and the lunar descent strategy. Various aspects of the GNC design of autonomous lunar descent maneuver: timeline of events, guidance, inertial and optical terrain-relative navigation schemes are described. The GNC software description focuses on system architecture, modes of operation, and core elements of the GNC software. The GNC algorithms have been tested using Monte-Carlo simulations and Processor-in-Loop runs. The paper concludes with a summary of key risk-mitigation studies for soft landing.

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V. Vatsal, C. Barath, J. Yogeshwaran, et. al.
Fri, 26 Jul 19
70/84

Comments: N/A

Motion Planning on an Asteroid Surface with Irregular Gravity Fields [CL]

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http://arxiv.org/abs/1902.02065


There are thousands of asteroids in near-Earth space and millions in the Main Belt. They are diverse in physical properties and composition and are time capsules of the early solar system. This makes them strategic locations for planetary science, resource mining, planetary defense/security and as inter-planetary depots and communication relays. However, asteroids are a chal-lenging target for surface exploration due it its low but highly nonlinear gravity field. In such conditions, mobility through ballistic hopping possess multiple advantages over conventional mobility solutions and as such hop-ping robots have emerged as a promising platform for future exploration of asteroids and comets. They can traverse large distances over rough terrain with the expenditure of minimum energy. In this paper we present ballistic hopping dynamics and its motion planning on an asteroid surface with highly nonlinear gravity fields. We do it by solving Lambert’s orbital boundary val-ue problem in irregular gravity fields by a shooting method to find the initial velocity required to intercept a target. We then present methods to localize the hopping robot using pose estimation by successive scan matching with a 3D laser scanner. Using the above results, we provide methods for motion planning on the asteroid surface over long distances. The robot will require to perform multiple hops to reach a desired goal from its initial position while avoiding obstacles. The study is then be extended to find optimal tra-jectories to reach a desired goal by visiting multiple waypoints.

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H. Kalita and J. Thangavelautham
Thu, 7 Feb 19
44/62

Comments: 11 pages, 8 figures, AAS Guidance Navigation and Control Conference, 2019

End to End Satellite Servicing and Space Debris Management [CL]

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http://arxiv.org/abs/1901.11121


There is growing demand for satellite swarms and constellations for global positioning, remote sensing and relay communication in higher LEO orbits. This will result in many obsolete, damaged and abandoned satellites that will remain on-orbit beyond 25 years. These abandoned satellites and space debris maybe economically valuable orbital real-estate and resources that can be reused, repaired or upgraded for future use. Space traffic management is critical to repair damaged satellites, divert satellites into warehouse orbits and effectively de-orbit satellites and space debris that are beyond repair and salvage. Current methods for on-orbit capture, servicing and repair require a large service satellite. However, by accessing abandoned satellites and space debris, there is an inherent heightened risk of damage to a servicing spacecraft. Sending multiple small-robots with each robot specialized in a specific task is a credible alternative, as the system is simple and cost-effective and where loss of one or more robots does not end the mission. In this work, we outline an end to end multirobot system to capture damaged and abandoned spacecraft for salvaging, repair and for de-orbiting. We analyze the feasibility of sending multiple, decentralized robots that can work cooperatively to perform capture of the target satellite as a first step, followed by crawling onto damage satellites to perform detailed mapping. After obtaining a detailed map of the satellite, the robots will proceed to either repair and replace or dismantle components for salvage operations. Finally, the remaining components will be packaged with a de-orbit device for accelerated de-orbit.

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A. Chandra, H. Kalita, R. Furfaro, et. al.
Fri, 1 Feb 19
38/61

Comments: 13 pages, 10 figures, Space Traffic Management Conference. arXiv admin note: text overlap with arXiv:1809.02028, arXiv:1809.04459, arXiv:1901.09710

Laser Communication and Coordination Control of Spacecraft Swarms [IMA]

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http://arxiv.org/abs/1901.08875


Swarms of small spacecraft offer whole new capabilities in Earth observation, global positioning and communications compared to a large monolithic spacecraft. These small spacecrafts can provide bigger apertures that increase gain in communication antennas, increase area coverage or effective resolution of distributed cameras and enable persistent observation of ground or space targets. However, there remain important challenges in operating large number of spacecrafts at once. Current methods would require a large number of ground operators monitor and actively control these spacecrafts which poses challenges in terms of coordination and control which prevents the technology from scaled up in cost-effective manner. Technologies are required to enable one ground operator to manage tens if not hundreds of spacecrafts. We propose to utilize laser beams directed from the ground or from a command and control spacecraft to organize and manage a large swarm. Each satellite in the swarm will have a customized “smart skin” con-taining solar panels, power and control circuitry and an embedded secondary propulsion unit. A secondary propulsion unit may include electrospray pro-pulsion, solar radiation pressure-based system, photonic laser thrusters and Lorentz force thrusters. Solar panels typically occupy the largest surface area on an earth orbiting satellite. A laser beam from another spacecraft or from the ground would interact with solar panels of the spacecraft swarm. The laser beam would be used to select a ‘leader’ amongst a group of spacecrafts, set parameters for formation-flight, including separation distance, local if-then rules and coordinated changes in attitude and position.

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H. Kalita, L. Vance, V. Reddy, et. al.
Mon, 28 Jan 19
55/55

Comments: 11 pages, 10 figures, Space Traffic Management Conference 2019

Mobility and Science operations On An Asteroid Using a Hopping Small Spacecraft on Stilts [CL]

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http://arxiv.org/abs/1801.09482


There are thousands of asteroids in near-Earth space and millions in the Main Belt. They are diverse in physical properties and composition and are time capsules of the early solar system. This makes them strategic locations for planetary science, resource mining, planetary defense/security and as interplanetary depots and communication relays. Landing on a small asteroid and manipulating its surface materials remains a major unsolved challenge fraught with high risk. The asteroid surface may contain everything from hard boulders to soft regolith loosely held by cohesion and very low-gravity. Upcoming missions Hayabusa II and OSIRIS-REx will perform touch and go operations to mitigate the risks of landing on an asteroid. This limits the contact time and requires fuel expenditure for hovering. An important unknown is the problem of getting stuck or making a hard impact with the surface. The Spacecraft Penetrator for Increasing Knowledge of NEOs (SPIKE) mission concept will utilize a small-satellite bus that is propelled using a xenon-fueled ion engine and will contain an extendable, low-mass, high-strength boom with a tip containing force-moment sensors. SPIKE will enable contact with the asteroid surface, where it will perform detailed regolith analysis and seismology as well as penetrometry, while keeping the main spacecraft bus at a safe distance. Using one or more long stilts frees the spacecraft from having to hover above the asteroid and thus substantially reduces or eliminates fuel use when doing science operations. This enables much longer missions that include a series of hops to multiple locations on the small-body surface.

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H. Kalita, S. Schwartz, E. Asphaug, et. al.
Tue, 30 Jan 18
66/70

Comments: 13 pages, 9 figures, to Appear at AAS GNC 2018/Advances in Astronautical Sciences 2018

An Information Theoretic Approach to Sample Acquisition and Perception in Planetary Robotics [CL]

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http://arxiv.org/abs/1709.04617


An important and emerging component of planetary exploration is sample retrieval and return to Earth. Obtaining and analyzing rock samples can provide unprecedented insight into the geology, geo-history and prospects for finding past life and water. Current methods of exploration rely on mission scientists to identify objects of interests and this presents major operational challenges. Finding objects of interests will require systematic and efficient methods to quickly and correctly evaluate the importance of hundreds if not thousands of samples so that the most interesting are saved for further analysis by the mission scientists. In this paper, we propose an automated information theoretic approach to identify shapes of interests using a library of predefined interesting shapes. These predefined shapes maybe human input or samples that are then extrapolated by the shape matching system using the Superformula to judge the importance of newly obtained objects. Shape samples are matched to a library of shapes using the eigenfaces approach enabling categorization and prioritization of the sample. The approach shows robustness to simulated sensor noise of up to 20%. The effect of shape parameters and rotational angle on shape matching accuracy has been analyzed. The approach shows significant promise and efforts are underway in testing the algorithm with real rock samples.

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G. Fleetwood and J. Thangavelautham
Fri, 15 Sep 17
26/57

Comments: 8 pages, 16 figures, Adaptive Hardware Systems Conference 2017

Optimized Bucket Wheel Design for Asteroid Excavation [CL]

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http://arxiv.org/abs/1701.07547


Current spacecraft need to launch with all of their required fuel for travel. This limits the system performance, payload capacity, and mission flexibility. One compelling alternative is to perform In-Situ Resource Utilization (ISRU) by extracting fuel from small bodies in local space such as asteroids or small satellites. Compared to the Moon or Mars, the microgravity on an asteroid demands a fraction of the energy for digging and accessing hydrated regolith just below the surface. Previous asteroid excavation efforts have focused on discrete capture events (an extension of sampling technology) or whole-asteroid capture and processing. This paper proposes an optimized bucket wheel design for surface excavation of an asteroid or small-body. Asteroid regolith is excavated and water extracted for use as rocket propellant. Our initial study focuses on system design, bucket wheel mechanisms, and capture dynamics applied to ponded materials known to exist on asteroids like Itokawa and Eros and small satellites like Phobos and Deimos. For initial evaluation of material-spacecraft dynamics and mechanics, we assume lunar-like regolith for bulk density, particle size and cohesion. We shall present our estimates for the energy balance of excavation and processing versus fuel gained. Conventional electrolysis of water is used to produce hydrogen and oxygen. It is compared with steam for propulsion and both show significant delta-v. We show that a return trip from Deimos to Earth is possible for a 12 kg craft using ISRU processed fuel.

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R. Nallapu, A. Thoesen, L. Garvie, et. al.
Fri, 27 Jan 17
15/54

Comments: 9 pages, 16 figures, International Astronautic Congress 2016, Guadalajara, Mexico

Spherical Planetary Robot for Rugged Terrain Traversal [CL]

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http://arxiv.org/abs/1701.07544


Wheeled planetary rovers such as the Mars Exploration Rovers (MERs) and Mars Science Laboratory (MSL) have provided unprecedented, detailed images of the Mars surface. However, these rovers are large and are of high-cost as they need to carry sophisticated instruments and science laboratories. We propose the development of low-cost planetary rovers that are the size and shape of cantaloupes and that can be deployed from a larger rover. The rover named SphereX is 2 kg in mass, is spherical, holonomic and contains a hopping mechanism to jump over rugged terrain. A small low-cost rover complements a larger rover, particularly to traverse rugged terrain or roll down a canyon, cliff or crater to obtain images and science data. While it may be a one-way journey for these small robots, they could be used tactically to obtain high-reward science data. The robot is equipped with a pair of stereo cameras to perform visual navigation and has room for a science payload. In this paper, we analyze the design and development of a laboratory prototype. The results show a promising pathway towards development of a field system.

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L. Raura, A. Warren and J. Thangavelautham
Fri, 27 Jan 17
18/54

Comments: 10 pages, 16 figures in Proceedings of the IEEE Aerospace Conference 2017

GNC of the SphereX Robot for Extreme Environment Exploration on Mars [CL]

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http://arxiv.org/abs/1701.07550


Wheeled ground robots are limited from exploring extreme environments such as caves, lava tubes and skylights. Small robots that can utilize unconventional mobility through hopping, flying or rolling can overcome these limitations. Mul-tiple robots operating as a team offer significant benefits over a single large ro-bot, as they are not prone to single-point failure, enable distributed command and control and enable execution of tasks in parallel. These robots can complement large rovers and landers, helping to explore inaccessible sites, obtaining samples and for planning future exploration missions. Our robots, the SphereX, are 3-kg in mass, spherical and contain computers equivalent to current smartphones. They contain an array of guidance, navigation and control sensors and electronics. SphereX contains room for a 1-kg science payload, including for sample return. Our work in this field has recognized the need for miniaturized chemical mobility systems that provide power and propulsion. Our research explored the use of miniature rockets, including solid rockets, bi-propellants including RP1/hydrogen-peroxide and polyurethane/ammonium-perchlorate. These propulsion options provide maximum flight times of 10 minutes on Mars. Flying, especially hovering consumes significant fuel; hence, we have been developing our robots to perform ballistic hops that enable the robots to travel efficiently over long distances. Techniques are being developed to enable mid-course correction during a ballistic hop. Using multiple cameras, it is possible to reconstitute an image scene from motion blur. Hence our approach is to enable photo mapping as the robots travel on a ballistic hop. The same images would also be used for navigation and path planning. Using our proposed design approach, we are developing low-cost methods for surface exploration of planetary bodies using a network of small robots.

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H. Kalita, R. Nallapu, A. Warren, et. al.
Fri, 27 Jan 17
32/54

Comments: 12 pages, 10 figures in Proceedings of the 40th Annual AAS Guidance, Navigation and Control Conference, 2017

FPGA Architecture for Deep Learning and its application to Planetary Robotics [CL]

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http://arxiv.org/abs/1701.07543


Autonomous control systems onboard planetary rovers and spacecraft benefit from having cognitive capabilities like learning so that they can adapt to unexpected situations in-situ. Q-learning is a form of reinforcement learning and it has been efficient in solving certain class of learning problems. However, embedded systems onboard planetary rovers and spacecraft rarely implement learning algorithms due to the constraints faced in the field, like processing power, chip size, convergence rate and costs due to the need for radiation hardening. These challenges present a compelling need for a portable, low-power, area efficient hardware accelerator to make learning algorithms practical onboard space hardware. This paper presents a FPGA implementation of Q-learning with Artificial Neural Networks (ANN). This method matches the massive parallelism inherent in neural network software with the fine-grain parallelism of an FPGA hardware thereby dramatically reducing processing time. Mars Science Laboratory currently uses Xilinx-Space-grade Virtex FPGA devices for image processing, pyrotechnic operation control and obstacle avoidance. We simulate and program our architecture on a Xilinx Virtex 7 FPGA. The architectural implementation for a single neuron Q-learning and a more complex Multilayer Perception (MLP) Q-learning accelerator has been demonstrated. The results show up to a 43-fold speed up by Virtex 7 FPGAs compared to a conventional Intel i5 2.3 GHz CPU. Finally, we simulate the proposed architecture using the Symphony simulator and compiler from Xilinx, and evaluate the performance and power consumption.

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P. Gankidi and J. Thangavelautham
Fri, 27 Jan 17
35/54

Comments: 8 pages, 10 figures in Proceedings of the IEEE Aerospace Conference 2017

Guidance, Navigation and Control of Multirobot Systems in Cooperative Cliff Climbing [CL]

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http://arxiv.org/abs/1701.07553


The application of GNC devices on small robots is a game-changer that enables these robots to be mobile on low-gravity planetary surfaces and small bodies. Use of reaction wheels enables these robots to roll, hop, summersault and rest on precarious/sloped surfaces that would otherwise not be possible with conven-tional wheeled robots. We are extending this technology to enable robots to climb off-world canyons, cliffs and caves. A single robot may slip and fall, however, a multirobot system can work cooperatively by being interlinked using spring-tethers and work much like a team of mountaineers to systematically climb a slope. A multirobot system as we will show in this paper can climb sur-faces not possible with a single robot alone. We consider a team of four robots that are interlinked with tethers in an ‘x’ configuration. Each robot secures itself to a slope using spiny gripping actuators, and one by one each robot moves up-wards by crawling, rolling or hopping up the slope. If any one of the robots loses grip, slips or falls, the remaining robots will be holding it up as they are anchored. This distributed controls approach to cliff climbing enables the system to reconfigure itself where possible and avoid getting stuck at one hard to reach location. Instead, the risk is distributed and through close cooperation, the robots can identify multiple trajectories to climb a cliff or rugged surface. The benefits can also be realized on milligravity surfaces such as asteroids. Too fast a jump can result in the robot flying off the surface into space. Having multiple robots anchored to the surface keeps the entire system secure. Our work combines dynamics and control simulation to evaluate the feasibility of our approach. The simulation results show a promising pathway towards advanced development of this technology on a team of real robots.

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H. Kalita, R. Nallapu, A. Warren, et. al.
Fri, 27 Jan 17
49/54

Comments: 14 pages, 13 figures in Proceedings of the 40th Annual AAS Guidance, Navigation and Control Conference, 2017

Flying, Hopping Pit-Bots for Cave and Lava Tube Exploration on the Moon and Mars [CL]

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http://arxiv.org/abs/1701.07799


Wheeled ground robots are limited from exploring extreme environments such as caves, lava tubes and skylights. Small robots that utilize unconventional mobility through hopping, flying and rolling can overcome many roughness limitations and thus extend exploration sites of interest on Moon and Mars. In this paper we introduce a network of 3 kg, 0.30 m diameter ball robots (pit-bots) that can fly, hop and roll using an onboard miniature propulsion system. These pit-bots can be deployed from a lander or large rover. Each robot is equipped with a smartphone sized computer, stereo camera and laser rangefinder to per-form navigation and mapping. The ball robot can carry a payload of 1 kg or perform sample return. Our studies show a range of 5 km and 0.7 hours flight time on the Moon.

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J. Thangavelautham, M. Robinson, A. Taits, et. al.
Fri, 27 Jan 17
53/54

Comments: in Proceedings of the 2nd International Workshop on Instrumentation for Planetary Missions 2014