The Starling Formation-Flying Optical Experiment (StarFOX) is intended as the first on-orbit demonstration of autonomous distributed angles-only navigation for spacecraft swarms. StarFOX applies the angles-only Absolute and Relative Trajectory System (ARTMS), a navigation architecture consisting of three innovative algorithms: image processing, which identifies and tracks multiple targets in images from a single camera without a priori relative orbit knowledge; batch orbit determination, which autonomously initializes orbit estimates for visible swarm members; and sequential orbit determination, which continuously refines the swarm state by fusing measurements from multiple observers exchanged over an intersatellite link. Nonlinear dynamics and measurement models provide sufficient observability to estimate absolute orbits, relative orbits, and auxiliary states using only bearing angles without maneuvers. StarFOX will be conducted using a four-CubeSat swarm as part of the NASA Starling mission, and simulations of experiment scenarios demonstrate that ARTMS meets mission performance requirements. Results indicate that mean bearing angle errors are below 35′′ ([Formula: see text]), initial target range errors are below 20% of true separation, and steady-state range errors are below 2% ([Formula: see text]). Absolute orbit estimation accuracy is on the order of 100 m. Hardware-in-the-loop tests display robust navigation under a variety of conditions, enabling autonomous, ubiquitous navigation with minimal ground interaction for future distributed missions.
{"title":"Starling Formation-Flying Optical Experiment (StarFOX): System Design and Preflight Verification","authors":"J. Kruger, Adam W. Koenig, S. D’Amico","doi":"10.2514/1.a35598","DOIUrl":"https://doi.org/10.2514/1.a35598","url":null,"abstract":"The Starling Formation-Flying Optical Experiment (StarFOX) is intended as the first on-orbit demonstration of autonomous distributed angles-only navigation for spacecraft swarms. StarFOX applies the angles-only Absolute and Relative Trajectory System (ARTMS), a navigation architecture consisting of three innovative algorithms: image processing, which identifies and tracks multiple targets in images from a single camera without a priori relative orbit knowledge; batch orbit determination, which autonomously initializes orbit estimates for visible swarm members; and sequential orbit determination, which continuously refines the swarm state by fusing measurements from multiple observers exchanged over an intersatellite link. Nonlinear dynamics and measurement models provide sufficient observability to estimate absolute orbits, relative orbits, and auxiliary states using only bearing angles without maneuvers. StarFOX will be conducted using a four-CubeSat swarm as part of the NASA Starling mission, and simulations of experiment scenarios demonstrate that ARTMS meets mission performance requirements. Results indicate that mean bearing angle errors are below 35′′ ([Formula: see text]), initial target range errors are below 20% of true separation, and steady-state range errors are below 2% ([Formula: see text]). Absolute orbit estimation accuracy is on the order of 100 m. Hardware-in-the-loop tests display robust navigation under a variety of conditions, enabling autonomous, ubiquitous navigation with minimal ground interaction for future distributed missions.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48923132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes an adaptive estimation algorithm for orbit determination, which consists of a deep-neural-network (DNN)-based nonlinearity detector combined with an adaptive order-switching procedure, to reduce the computational complexity while still maintaining the estimation accuracy. The DNN is trained to quickly evaluate the nonlinearity degree of the state equation. An adaptive order-switching strategy is designed based on the nonlinearity degree predicted by the DNN. The algorithm switches to a high-order method when the nonlinearity of the state equation is significant and uses a linear method when the nonlinearity degree is low. The proposed method is applied to estimate the orbit of a spacecraft in cislunar space. The sample forms in the inertial frame and rotating frame are investigated and compared to find the optimum one to train the DNN. Simulations show that the proposed method can deliver accurate state estimations comparable with the state estimations obtained by the second-order extended Kalman filter but with only half of the computational cost.
{"title":"Adaptive Order-Switching Kalman Filter for Orbit Determination Using Deep-Neural-Network-Based Nonlinearity Detection","authors":"Xingyu Zhou, D. Qiao, Xiangyu Li","doi":"10.2514/1.a35639","DOIUrl":"https://doi.org/10.2514/1.a35639","url":null,"abstract":"This paper proposes an adaptive estimation algorithm for orbit determination, which consists of a deep-neural-network (DNN)-based nonlinearity detector combined with an adaptive order-switching procedure, to reduce the computational complexity while still maintaining the estimation accuracy. The DNN is trained to quickly evaluate the nonlinearity degree of the state equation. An adaptive order-switching strategy is designed based on the nonlinearity degree predicted by the DNN. The algorithm switches to a high-order method when the nonlinearity of the state equation is significant and uses a linear method when the nonlinearity degree is low. The proposed method is applied to estimate the orbit of a spacecraft in cislunar space. The sample forms in the inertial frame and rotating frame are investigated and compared to find the optimum one to train the DNN. Simulations show that the proposed method can deliver accurate state estimations comparable with the state estimations obtained by the second-order extended Kalman filter but with only half of the computational cost.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48416669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vishal Arya, Keziban Saloglu, E. Taheri, J. Junkins
Impulsive trajectories provide time- and [Formula: see text]-reachability insights. Two novel homotopy-based methods are proposed for generating optimal many-impulse, multirevolution maneuvers. The first method is based on the continuation over the specific impulse value, which is shown to enhance convergence performance of the resulting two-point boundary-value problems. The second method is based on the formulation of impulsive trajectories using a linear acceleration term. The two methods are used in a hybrid framework. The utility of the proposed methods is demonstrated on four problems: Two interplanetary trajectories 1) from Earth to Mars, 2) from Earth to asteroid Dionysus, 3) a planet-centric transfer maneuver from a geostationary transfer orbit (GTO) to geostationary orbit (GEO) consisting of 21 revolutions, and 4) a 50-revolution transfer from the considered GTO to a circular orbit at the first Lagrange point (L1) of the Earth–moon system. The last two problems leading to 18 and 50 impulses are tackled to give an optimal near-impulsive solution. The impulsive solution with 18 impulses is shown to satisfy Lawden’s conditions.
{"title":"Generation of Multiple-Revolution Many-Impulse Optimal Spacecraft Maneuvers","authors":"Vishal Arya, Keziban Saloglu, E. Taheri, J. Junkins","doi":"10.2514/1.a35638","DOIUrl":"https://doi.org/10.2514/1.a35638","url":null,"abstract":"Impulsive trajectories provide time- and [Formula: see text]-reachability insights. Two novel homotopy-based methods are proposed for generating optimal many-impulse, multirevolution maneuvers. The first method is based on the continuation over the specific impulse value, which is shown to enhance convergence performance of the resulting two-point boundary-value problems. The second method is based on the formulation of impulsive trajectories using a linear acceleration term. The two methods are used in a hybrid framework. The utility of the proposed methods is demonstrated on four problems: Two interplanetary trajectories 1) from Earth to Mars, 2) from Earth to asteroid Dionysus, 3) a planet-centric transfer maneuver from a geostationary transfer orbit (GTO) to geostationary orbit (GEO) consisting of 21 revolutions, and 4) a 50-revolution transfer from the considered GTO to a circular orbit at the first Lagrange point (L1) of the Earth–moon system. The last two problems leading to 18 and 50 impulses are tackled to give an optimal near-impulsive solution. The impulsive solution with 18 impulses is shown to satisfy Lawden’s conditions.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45590033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper concentrates on the long-term orbital lifetime prediction of highly eccentric orbits (HEOs) based on two-line element sets via a statistical approach. Due to the significantly different evolution characteristics of low- and high-inclination HEOs induced by different orbital resonances, two area-to-mass estimation methods are proposed, respectively. The resonance phenomena encountered in the HEO region strongly affect the orbital evolution and cause high sensitivity. Therefore, a statistical approach is adopted to handle these effects and correctly estimate low-inclination HEO lifetime. We use the Monte Carlo method and kernel-density estimation to calculate the probability distribution of the orbital lifetime. Finally, the performance of the method is assessed by the actual orbital lifetimes of space objects that reentered from HEOs in the past 50 years. The results indicate that our statistical approach can improve the orbital lifetime prediction accuracy to a large extent, especially for the low-inclination HEOs. If a relative error of 15% is adopted as the error tolerance, compared with the traditional method based on a single orbital propagation, our statistical method can increase the success rate from 40% to more than 70%. For the high-inclination HEOs, the objects with a relative error below 15% account for more than 90%.
{"title":"Long-Term Orbital Lifetime Prediction of Highly Eccentric Orbits: A Statistical Approach","authors":"Xuhui Luo, Yue Wang, Yao Zhang, Jing Liu","doi":"10.2514/1.a35706","DOIUrl":"https://doi.org/10.2514/1.a35706","url":null,"abstract":"This paper concentrates on the long-term orbital lifetime prediction of highly eccentric orbits (HEOs) based on two-line element sets via a statistical approach. Due to the significantly different evolution characteristics of low- and high-inclination HEOs induced by different orbital resonances, two area-to-mass estimation methods are proposed, respectively. The resonance phenomena encountered in the HEO region strongly affect the orbital evolution and cause high sensitivity. Therefore, a statistical approach is adopted to handle these effects and correctly estimate low-inclination HEO lifetime. We use the Monte Carlo method and kernel-density estimation to calculate the probability distribution of the orbital lifetime. Finally, the performance of the method is assessed by the actual orbital lifetimes of space objects that reentered from HEOs in the past 50 years. The results indicate that our statistical approach can improve the orbital lifetime prediction accuracy to a large extent, especially for the low-inclination HEOs. If a relative error of 15% is adopted as the error tolerance, compared with the traditional method based on a single orbital propagation, our statistical method can increase the success rate from 40% to more than 70%. For the high-inclination HEOs, the objects with a relative error below 15% account for more than 90%.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44648215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes a novel methodology to improve the preliminary design and efficiency analysis of the satellite’s electrical power subsystem. Several studies have addressed this issue by proposing a solar array sizing method based on the use of fixed efficiency paths during sunlight and eclipse periods. Indeed, these studies restrict the use of the battery for eclipse periods, and thus the solar array is sized to support the peak power loads on its own. To the authors’ knowledge, no one has so far deeply and jointly analyzed the influence of the power profile demand, the use of the battery during sunlight periods, and the architecture on the efficiency paths to size the electrical power subsystem. This work offers a methodology that takes into account these variables to better estimate the global efficiency of the electrical power subsystem and, consequently, to refine the first design iterations of a satellite. This methodology is particularized for the most common architectures based on power and voltage bus regulation, although it can be implemented in more complex architectures. A case study involving a real space mission, the UPMSat-2 (a 50 kg satellite launched in September 2020), is conducted to test this methodology.
{"title":"New Sizing Methodology and Efficiency Analysis of Satellite’s Electrical Power Subsystem","authors":"S. Marín-Coca, E. Roibás-Millán, S. Pindado","doi":"10.2514/1.a35609","DOIUrl":"https://doi.org/10.2514/1.a35609","url":null,"abstract":"This paper describes a novel methodology to improve the preliminary design and efficiency analysis of the satellite’s electrical power subsystem. Several studies have addressed this issue by proposing a solar array sizing method based on the use of fixed efficiency paths during sunlight and eclipse periods. Indeed, these studies restrict the use of the battery for eclipse periods, and thus the solar array is sized to support the peak power loads on its own. To the authors’ knowledge, no one has so far deeply and jointly analyzed the influence of the power profile demand, the use of the battery during sunlight periods, and the architecture on the efficiency paths to size the electrical power subsystem. This work offers a methodology that takes into account these variables to better estimate the global efficiency of the electrical power subsystem and, consequently, to refine the first design iterations of a satellite. This methodology is particularized for the most common architectures based on power and voltage bus regulation, although it can be implemented in more complex architectures. A case study involving a real space mission, the UPMSat-2 (a 50 kg satellite launched in September 2020), is conducted to test this methodology.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41819489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Koopman Operator (KO) theory is applied to generate an analytical solution of dynamical systems. The approach proposed in this work exploits a novel derivation of the KO with orthogonal polynomials to represent and propagate uncertainties, where the polynomials are modified to work with stochastic variables. Thus, a new uncertainty quantification technique is proposed in which the KO solution is expanded to include the prediction of central moments, up to an arbitrary order. The propagation of uncertainties is then expanded to develop a new filtering algorithm, for which the measurements are considered as additional observables in the KO mathematics. The uncertainty propagation technique is tested by predicting the state probability density function of a spacecraft in a halo orbit. The performance of the technique is assessed with a Monte Carlo analysis and proven to obtain accurate estimates for the state covariance, skewness, and kurtosis. The novel filtering methodology is then applied to an orbit determination application regarding a Lyapunov orbit, where an analysis on the filter accuracy and consistency shows that the new KO filter outperforms other common estimators.
{"title":"Uncertainty Propagation and Filtering via the Koopman Operator in Astrodynamics","authors":"Simone Servadio, W. Parker, R. Linares","doi":"10.2514/1.a35688","DOIUrl":"https://doi.org/10.2514/1.a35688","url":null,"abstract":"The Koopman Operator (KO) theory is applied to generate an analytical solution of dynamical systems. The approach proposed in this work exploits a novel derivation of the KO with orthogonal polynomials to represent and propagate uncertainties, where the polynomials are modified to work with stochastic variables. Thus, a new uncertainty quantification technique is proposed in which the KO solution is expanded to include the prediction of central moments, up to an arbitrary order. The propagation of uncertainties is then expanded to develop a new filtering algorithm, for which the measurements are considered as additional observables in the KO mathematics. The uncertainty propagation technique is tested by predicting the state probability density function of a spacecraft in a halo orbit. The performance of the technique is assessed with a Monte Carlo analysis and proven to obtain accurate estimates for the state covariance, skewness, and kurtosis. The novel filtering methodology is then applied to an orbit determination application regarding a Lyapunov orbit, where an analysis on the filter accuracy and consistency shows that the new KO filter outperforms other common estimators.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49559729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ionuț Bunescu, Mihai-Vlăduţ Hothazie, Mihai-Victor Pricop, M. G. Stoican
Determination of aerodynamic damping coefficients has always been difficult due to the dynamic nature of measurements for both forced and free methods. Although aerodynamic damping identification is available since the 1960s, this testing capability is not available in most of the high-speed wind tunnels due to its complexity, although the aerodynamic damping coefficients are needed for every aerospace vehicle. Herein are presented the development of the rig for roll damping determination, which uses both free and forced methods in the working cycle; the calibration process using the basic Finner model with reference data; and the experimental results obtained. Also, considering the challenges for computational fluid dynamics to match the experimental results, numerical results are presented for the calibration points required for interpolation of the roll damping coefficient along a Mach number range. The calibration points cover all regimes from subsonic to supersonic at Mach numbers ranging between 0.4 and 3.5. Conclusions are presented, focusing on the comparison between forced and free methods, as well as the rotation direction, considering the flow deflection that is increasing the level of uncertainty.
{"title":"Roll Damping Measurements on Basic Finner Model Using Both Forced and Free Methods","authors":"Ionuț Bunescu, Mihai-Vlăduţ Hothazie, Mihai-Victor Pricop, M. G. Stoican","doi":"10.2514/1.a35687","DOIUrl":"https://doi.org/10.2514/1.a35687","url":null,"abstract":"Determination of aerodynamic damping coefficients has always been difficult due to the dynamic nature of measurements for both forced and free methods. Although aerodynamic damping identification is available since the 1960s, this testing capability is not available in most of the high-speed wind tunnels due to its complexity, although the aerodynamic damping coefficients are needed for every aerospace vehicle. Herein are presented the development of the rig for roll damping determination, which uses both free and forced methods in the working cycle; the calibration process using the basic Finner model with reference data; and the experimental results obtained. Also, considering the challenges for computational fluid dynamics to match the experimental results, numerical results are presented for the calibration points required for interpolation of the roll damping coefficient along a Mach number range. The calibration points cover all regimes from subsonic to supersonic at Mach numbers ranging between 0.4 and 3.5. Conclusions are presented, focusing on the comparison between forced and free methods, as well as the rotation direction, considering the flow deflection that is increasing the level of uncertainty.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46740525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Designing optimal transfer trajectories and reference orbit tracking in binary asteroid systems is both challenging and computationally expensive. This paper proposes a method of bypassing the high computational overhead by leveraging a collection of known techniques. Indeed, the proposed framework is based on the combination of artificial intelligence techniques, such as the particle swarm optimization and neural networks, along with the inverse dynamics and the B-splines approximation of the trajectory. The real irregular shapes of the asteroids are considered in the free dynamics of the system, which are obtained via the mutual polyhedral model. The gravitational accelerations of the single asteroids acting on the spacecraft are approximated by using two single-layer neural networks trained via an extreme learning machine. By using a combination of these techniques, the computational time of the whole optimization is decreased from hours to minutes. The proposed approach is applied to the optimal trajectory design around the binary asteroid system, 1999 KW4, showing the feasibility of the proposed optimization approach, reducing the computational effort and time, and increasing the reliability of the obtained results. It is shown through a Monte Carlo analysis that our optimization strategy yields more accurate solutions than other optimization algorithms, such as the interior point and sequential quadratic programming methods, when a random initial guess is provided. Finally, the proposed optimization approach can be used in combination with other techniques to provide a feasible and reliable initial guess for a better solution refinement.t
{"title":"Optimal Maneuvers Around Binary Asteroids Using Particle Swarm Optimization and Machine Learning","authors":"A. D’Ambrosio, A. Carbone, F. Curti","doi":"10.2514/1.a35317","DOIUrl":"https://doi.org/10.2514/1.a35317","url":null,"abstract":"Designing optimal transfer trajectories and reference orbit tracking in binary asteroid systems is both challenging and computationally expensive. This paper proposes a method of bypassing the high computational overhead by leveraging a collection of known techniques. Indeed, the proposed framework is based on the combination of artificial intelligence techniques, such as the particle swarm optimization and neural networks, along with the inverse dynamics and the B-splines approximation of the trajectory. The real irregular shapes of the asteroids are considered in the free dynamics of the system, which are obtained via the mutual polyhedral model. The gravitational accelerations of the single asteroids acting on the spacecraft are approximated by using two single-layer neural networks trained via an extreme learning machine. By using a combination of these techniques, the computational time of the whole optimization is decreased from hours to minutes. The proposed approach is applied to the optimal trajectory design around the binary asteroid system, 1999 KW4, showing the feasibility of the proposed optimization approach, reducing the computational effort and time, and increasing the reliability of the obtained results. It is shown through a Monte Carlo analysis that our optimization strategy yields more accurate solutions than other optimization algorithms, such as the interior point and sequential quadratic programming methods, when a random initial guess is provided. Finally, the proposed optimization approach can be used in combination with other techniques to provide a feasible and reliable initial guess for a better solution refinement.t","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43321305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ESA/JAXA (Japan Aerospace Exploration Agency) BepiColombo mission is currently in its cruise phase and is set to reach Mercury in late 2025. The spacecraft is equipped with advanced radio-tracking instrumentation that provides accurate radiometric data for precise orbit determination (POD). During the cruise phase, the radio link enables tests of general relativity (GR) and measurements of the solar corona properties. To fully exploit the accuracy of the radiometric measurements (Doppler and ranging) and to obtain better accuracies in the GR tests, a comprehensive dynamical model of the spacecraft is needed. A reliable and precise model of the non-gravitational accelerations would maximize the scientific return of the radio-science experiments and prevent unmodeled dynamic perturbations from degrading the POD solution. In this work, we investigate the effects of non-conservative forces acting on BepiColombo during three different radio-science campaigns conducted in November 2020, March 2021, and February 2022. The last two periods correspond to the first two GR tests of BepiColombo. We design a method for modeling these forces using telemetry measurements, radiometric observables, and mathematical models; and we analyze their characteristics in relation to the different environments encountered by the spacecraft during the three periods. This work is a preparatory and unavoidable step for the data analysis of the first two GR experiments of BepiColombo and the next radio-science campaigns, which will be performed in an even more challenging dynamical environment.
{"title":"Precise Modeling of Non-Gravitational Accelerations of the Spacecraft BepiColombo During Cruise Phase","authors":"I. di Stefano, P. Cappuccio, L. Iess","doi":"10.2514/1.a35704","DOIUrl":"https://doi.org/10.2514/1.a35704","url":null,"abstract":"The ESA/JAXA (Japan Aerospace Exploration Agency) BepiColombo mission is currently in its cruise phase and is set to reach Mercury in late 2025. The spacecraft is equipped with advanced radio-tracking instrumentation that provides accurate radiometric data for precise orbit determination (POD). During the cruise phase, the radio link enables tests of general relativity (GR) and measurements of the solar corona properties. To fully exploit the accuracy of the radiometric measurements (Doppler and ranging) and to obtain better accuracies in the GR tests, a comprehensive dynamical model of the spacecraft is needed. A reliable and precise model of the non-gravitational accelerations would maximize the scientific return of the radio-science experiments and prevent unmodeled dynamic perturbations from degrading the POD solution. In this work, we investigate the effects of non-conservative forces acting on BepiColombo during three different radio-science campaigns conducted in November 2020, March 2021, and February 2022. The last two periods correspond to the first two GR tests of BepiColombo. We design a method for modeling these forces using telemetry measurements, radiometric observables, and mathematical models; and we analyze their characteristics in relation to the different environments encountered by the spacecraft during the three periods. This work is a preparatory and unavoidable step for the data analysis of the first two GR experiments of BepiColombo and the next radio-science campaigns, which will be performed in an even more challenging dynamical environment.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48949926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper discusses a flush air-data sensing (FADS) system for a sharp-nosed hypersonic vehicle designed to estimate flight air data in real time at hypersonic speeds. The design’s target condition is Mach 5.0 to 7.0 with an angle of attack within 5 deg. The FADS system estimates air data by relating them to surface pressures measured from surface-mounted ports on the vehicle forebody. Unique combinations of pressure ratios were used to estimate the freestream dynamic pressure, which was a primary parameter for the flight experiment, the angle of attack, and the Mach number. The proposed FADS estimation algorithm was validated through numerical simulation, which was also used to generate datasets of surface pressures for given flight conditions. To handle possible sensor errors related to estimation accuracy in real-time estimation for a flight experiment, redundant systems were implemented. The results indicated that the designed FADS system can estimate air data within the uncertainty of 4.8% for a single estimator by considering sensor errors for freestream dynamic pressures in the range of 0–100 kPa, including targeted and off-design flight conditions. The proposed algorithm can estimate the air data with an acceptable level of uncertainty while retaining the robustness of estimation to sensor failures with low computational cost.
{"title":"Simplified Real-Time Flush Air-Data Sensing System for Sharp-Nosed Hypersonic Vehicles","authors":"Hidemi Takahashi, S. Hasegawa, K. Tani","doi":"10.2514/1.a35634","DOIUrl":"https://doi.org/10.2514/1.a35634","url":null,"abstract":"This paper discusses a flush air-data sensing (FADS) system for a sharp-nosed hypersonic vehicle designed to estimate flight air data in real time at hypersonic speeds. The design’s target condition is Mach 5.0 to 7.0 with an angle of attack within 5 deg. The FADS system estimates air data by relating them to surface pressures measured from surface-mounted ports on the vehicle forebody. Unique combinations of pressure ratios were used to estimate the freestream dynamic pressure, which was a primary parameter for the flight experiment, the angle of attack, and the Mach number. The proposed FADS estimation algorithm was validated through numerical simulation, which was also used to generate datasets of surface pressures for given flight conditions. To handle possible sensor errors related to estimation accuracy in real-time estimation for a flight experiment, redundant systems were implemented. The results indicated that the designed FADS system can estimate air data within the uncertainty of 4.8% for a single estimator by considering sensor errors for freestream dynamic pressures in the range of 0–100 kPa, including targeted and off-design flight conditions. The proposed algorithm can estimate the air data with an acceptable level of uncertainty while retaining the robustness of estimation to sensor failures with low computational cost.","PeriodicalId":50048,"journal":{"name":"Journal of Spacecraft and Rockets","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43552823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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