Spacecraft Formation Flying: Dynamics and Control

Kapila, Vikram; Sparks, Andrew G.; Buffington, James M.; Yan, Qiguo

doi:10.2514/2.4567

Cited by 226 publications

(87 citation statements)

References 4 publications

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“…The CW equations are very convenient to develop rendezvous and near-circular formation flying control laws. 15,16 With traditional spacecraft formation flying concepts, each craft contains its own inertial propulsion system, typically a high efficiency ion engine. As relative motion errors are detected, the thruster is used to correct the motion with respect to the rotating Hill frame.…”

Section: Relative Acceleration Magnitudesmentioning

confidence: 99%

Coulomb Thrusting Application Study

Schaub¹,

Parker²,

King³

2006

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Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. SummaryThis report discusses the results of an 8-month inter-disciplinary research project between Virginia Polytechnic Institute and State University and Aerophysics Inc. The research task objectives are to study how Coulomb propulsion can be used to create reconfigurable distributed spacecraft formation concepts. Both formation maintenance and deployment charge and voltage levels are of interest, as well as the required reconfiguration times to change the formation size. A further task is to study the space plasma environment at low to high Earth orbit altitudes. Associated to this task is the study of the expected differential disturbance levels that Coulomb spacecraft will experience at a range of orbit altitudes. Using the results of the plasma environment study, expected spacecraft voltages are to be computed to compensate for conservative orbital perturbation estimates. Another objective is to study mechanisms to both measure the local plasma charge level, and control the spacecraft charge relative to this plasma charge level. The final task is to perform a comparison study of the Coulomb propulsion concept to other high-efficiency propulsion concepts.The technical problems associated with Coulomb formation flying is determining the required charge level to achieve missions tasks such as deployment, orbit maintenance, formation reconfiguration, or docking maneuvers. Previously flown missions in the 70s have demonstrated that kilovolt level of charges are feasible. In this study we are assuming that this charge level can be safely increased to multiple hundreds of kilovolts using modern materials and manufacturing methods. A very challenging aspect of Coulomb thrusting based control is that these forces only act along the line of sight vector between spacecraft. As a result, the relative motion dynamics are very nonlinear and coupled, and can yield surprising, unexpected results. The current CLUSTERS mission uses Langmuir probes up to 25 meters in length to measure the local space plasma potential level very accurately. Their goal is to precisely zero the spacecraft potential relative to this plasma. With the Coulomb spacecraft control concept the craft are flying 10-100 meters apart, making such l...

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Section: Relative Acceleration Magnitudesmentioning

confidence: 99%

Coulomb Thrusting Application Study

Schaub¹,

Parker²,

King³

2006

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“…It allows that a group of small satellites, arranged in a space formation flying, operate like a large 'virtual satellite'. This formation will have many benefits over single satellites, including simpler designs, faster build times, cheaper and unprecedented high resolution (Kapila et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Natural formations at the Earth–Moon triangular point in perturbed restricted problems

Salazar

Winter

Macau

et al. 2015

Advances in Space Research

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Previous studies for small formation flying dynamics about triangular libration points have determined the existence of regions of zero and minimum relative radial acceleration with respect to the nominal trajectory, that prevent from the expansion or contraction of the constellation. However, these studies only considered the gravitational force of the Earth and the Moon using the Circular Restricted Three Body Problem (CRTBP) scenario. Although the CRTBP model is a good approximation for the dynamics of spacecraft in the Earth-Moon system, the nominal trajectories around equilateral libration points are strongly affected when the primary orbit eccentricity and solar gravitational force are considered. In this manner, the goal of this work is the analysis of the best regions to place a formation that is flying close a bounded solution around L 4 , taking into account the Moon's eccentricity and Sun's gravity. This model is not only more realistic for practical engineering applications but permits to determine more accurately the fuel consumption to maintain the geometry of the formation.

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“…Normally, this is done in postprocessing, where present techniques make use of GPS carrier phase measurements, attaining position accuracies of 5 cm with dual-frequency receivers and 10 cm with single-frequency receivers [1]. Nevertheless, some applications, such as Autonomous Formation Flying (AFF) [2] and Space Rendezvous and Docking (RVD) [3], require real time solutions. In this kind of processing, which obviously has to be done on the LEO satellite, the utilization of phase measurements is a more complex task, since it involves the on the fly estimation of the carrier phase ambiguities.…”

Section: Introductionmentioning

confidence: 99%

Real time GPS Positioning of LEO Satellites Mitigating Pseudorange Multipath through Neural Networks

et al. 2007

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A method for real-time positioning of LEO satellites using dual frequency GPS receivers is presented. It is based on an a priori ground estimation of a pseudorange multipath map computed by means of a Self-Organizing Map neural network algorithm. The generated map characterizes the multipath environment of the satellite. This a priori estimation allows a real time correction of the pseudorange observables onboard the LEO satellite with a number of parameters affordable for space applications in terms of CPU and memory usage. The novelty of the approach consists of the use of neural networks to reduce the number of parameters and the use of a hybrid offline-online method. Precise IGS clocks and orbits have been used to measure the impact of these corrections in the navigation solution. Improvements in 3D positioning error of about 40%-50% for SAC-C (obtaining errors $90cm) and 25%-35% for CHAMP (obtaining errors $70cm) are demonstrated.

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Spacecraft Formation Flying: Dynamics and Control

Cited by 226 publications

References 4 publications

Coulomb Thrusting Application Study

Coulomb Thrusting Application Study

Natural formations at the Earth–Moon triangular point in perturbed restricted problems

Real time GPS Positioning of LEO Satellites Mitigating Pseudorange Multipath through Neural Networks

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