Periodic Reporting for period 1 - ReMoVE (Rendezvous Modelling Visiting and Enhancing)
Berichtszeitraum: 2019-09-01 bis 2021-08-31
The ReMoVE (Rendezvous Modelling Visiting and Enhancing) Action addresses the problem of removing from space the large faulty satellites that are polluting strategical terrestrial orbits. The increasing number of inactive spacecraft orbiting around Earth, in fact, affects the probability of satellite explosions and collisions, which foster the growth of debris belts. The scientific community has recognised active debris removal as a key activity to be performed. ReMoVE investigates to which extend a small, agile, and modular satellite platform can be used to rendezvous a passive Target. The game-changing approach is embedded in the Enhancing concept: the ReMoVE platform acts as a smart and independent additive sub-system, to recover the capability to perform de-orbiting manoeuvres.
In the everyday life our society benefits and relies on several services that make use of satellites flying in terrestrial orbits. Hence, the presence of debris in space has a two-fold impact. First, the proper functioning of the satellites already in-orbit is endangered by possible collisions against these fragments. Second, the larger the debris population will become, the less the free space will remain available for new satellites for existing services or to set-up brand-new ones. Hence, the removal of large faulty satellites from the low Earth orbit region has a direct impact on the society. At the same time, since the ReMoVE Action focuses on the exploitation of low-cost small-size platforms, its outcomes pave the way to a future multi-player, distributed, and sustainable commitment to realise space debris removal.
The ReMoVE Action develops through three main objectives: 1. Safe close-range rendezvous to a passive Target. 2. Modelling and estimation of the roto-translational Target's motion. 3 Multi-purpose system design of the ReMoVE platform.
Based on the research carried out during the Action, the development of the ReMoVE small-size platform is technologically feasible. As for the relative GNC, which is a key sub-system for this kind of mission, the minimal sensors’ suite to enable far- to close-range navigation to a noncooperative targets has been identified. Moreover, specific algorithms have been developed to support the estimation of the relative navigation solution and the development of viable rendezvous trajectories. All these algorithms can be implemented on a spaceborne computer, to foster autonomy and therefore maximising the operational opportunities of ReMoVE.
In the everyday life our society benefits and relies on several services that make use of satellites flying in terrestrial orbits. Hence, the presence of debris in space has a two-fold impact. First, the proper functioning of the satellites already in-orbit is endangered by possible collisions against these fragments. Second, the larger the debris population will become, the less the free space will remain available for new satellites for existing services or to set-up brand-new ones. Hence, the removal of large faulty satellites from the low Earth orbit region has a direct impact on the society. At the same time, since the ReMoVE Action focuses on the exploitation of low-cost small-size platforms, its outcomes pave the way to a future multi-player, distributed, and sustainable commitment to realise space debris removal.
The ReMoVE Action develops through three main objectives: 1. Safe close-range rendezvous to a passive Target. 2. Modelling and estimation of the roto-translational Target's motion. 3 Multi-purpose system design of the ReMoVE platform.
Based on the research carried out during the Action, the development of the ReMoVE small-size platform is technologically feasible. As for the relative GNC, which is a key sub-system for this kind of mission, the minimal sensors’ suite to enable far- to close-range navigation to a noncooperative targets has been identified. Moreover, specific algorithms have been developed to support the estimation of the relative navigation solution and the development of viable rendezvous trajectories. All these algorithms can be implemented on a spaceborne computer, to foster autonomy and therefore maximising the operational opportunities of ReMoVE.
The main results of the first research stream deal with the development of convenient mathematical tools, applicable to the close-range domain and continuously thrusted trajectories. Within this mathematical framework, it has been developed a methodology to put into effect forced-motion phases as required to approach a satellite prior to docking. Both developed mathematical formulation and technique to generate piecewise constant forced motion profiles have been disseminated by the following peer-reviewed publication: Gaias, G., and Lovera, M., "Trajectory Design for Proximity Operations: The Relative Orbital Elements' Perspective", Journal of Guidance, Control, and Dynamics, 2021, https://doi.org/10.2514/1.G006175(öffnet in neuem Fenster).
As for the development of point-to-point guidance strategies to docking conditions, it has been developed a method to design impulsive guidance solutions specific for the final phase of the approach till docking, as explained in the publication: Gaias, G., and Lovera, M., "Safe Trajectory Design for Close Proximity Operations", Advances in the Astronautical Sciences, 2021, Vol. 175, AAS 20-641 paper.
The main results of the second research stream deal with the development and implementation of several filtering schemes; some of them capable to estimate simultaneously the relative roto-translational state and the main parameters of a noncooperative Target from an observing chaser satellite during close proximity operations.
The mathematical formulation of the coupled 6 DoF relative motion and preliminary results of the filter design have been disseminated by the following publication: Gaias, G., and Lovera, M., “6-DoF Relative State and Parameters Estimation for Close-Range Navigation to Noncooperative Targets,” 11th International Workshop on Satellite Constellations and Formation Flying, Politecnico di Milano, Milan, Italy, 2022.
The final results are currently under consideration for publication within a peer-reviewed journal.
Overall the research and implementation activities resulted in the development of the SKiLLeD-RdV (Simulation Kit for Logic and Layout Design of RdV) simulation environment. This is a simulation tool capable to support the modelling and verification of GNC algorithms for rendezvous missions. Accordingly, SKiLLeD-RdV can be further used in future phase 0/A studies of similar missions.
The main results of the ReMoVE application study deal with design the ReMoVE platform.
As for the development of point-to-point guidance strategies to docking conditions, it has been developed a method to design impulsive guidance solutions specific for the final phase of the approach till docking, as explained in the publication: Gaias, G., and Lovera, M., "Safe Trajectory Design for Close Proximity Operations", Advances in the Astronautical Sciences, 2021, Vol. 175, AAS 20-641 paper.
The main results of the second research stream deal with the development and implementation of several filtering schemes; some of them capable to estimate simultaneously the relative roto-translational state and the main parameters of a noncooperative Target from an observing chaser satellite during close proximity operations.
The mathematical formulation of the coupled 6 DoF relative motion and preliminary results of the filter design have been disseminated by the following publication: Gaias, G., and Lovera, M., “6-DoF Relative State and Parameters Estimation for Close-Range Navigation to Noncooperative Targets,” 11th International Workshop on Satellite Constellations and Formation Flying, Politecnico di Milano, Milan, Italy, 2022.
The final results are currently under consideration for publication within a peer-reviewed journal.
Overall the research and implementation activities resulted in the development of the SKiLLeD-RdV (Simulation Kit for Logic and Layout Design of RdV) simulation environment. This is a simulation tool capable to support the modelling and verification of GNC algorithms for rendezvous missions. Accordingly, SKiLLeD-RdV can be further used in future phase 0/A studies of similar missions.
The main results of the ReMoVE application study deal with design the ReMoVE platform.
The ReMoVE Action has provided several progress beyond the state of the art in the development of algorithms for the relative guidance navigation system of space rendezvous missions. Particularly, the mathematical framework set-up allows designing guidance and control policies subject to operational constraints completely in the relative orbital elements’ domain. This aspect is beneficial to the implementation of the algorithms on spaceborne processors. As for the navigation field, this Action developed a family of relative navigation filters that could serve different possible architectures of the close-range navigation system. Such a general approach is beneficial either to simplify the overall structure of the guidance, navigation and control system or to enhance its flexibility and adaptability to support the various phases of close proximity operations.
The progresses achieved by the developed algorithms can directly impact the design of the relative GNC systems of rendezvous missions (both devoted to ADR or to on-orbit-servicing). It is emphasised that, a large part of the results can be also exploited by other missions involving multiple satellites close to each other. Examples are the autonomous design of collision avoidance trajectories for formation flying missions or for satellites encountering debris in space.
Overall, the ReMoVE mission - intended as an ADR mission based on the use of the ReMoVE platform - introduces a new perspective in the architecture of removal missions. De facto, the ReMoVE satellite can be seen as an intelligent, autonomous, de-orbiting kit capable to reach by its own the target, to join it, and to “enhance” it. Accordingly, this mission philosophy differs from the classical de-orbiting kits attached to the target by a servicer satellite and differs from the standard approach of using a chaser satellite to capture a target object. ReMoVE could be seen as on-orbit-servicing applied to a debris removal mission.
The ReMoVE platform could be used to realise a multi-player and distributed ADR service for the LEO region. This would foresee to equip launchers by a ReMoVE platform in addition to their payloads. If a piece of debris can be reached in the following months (extremely likely to occur in LEO), it is then de-orbited, otherwise ReMoVE will re-enter not contributing to increase the number of objects in space. Secondary payloads might be embarked on ReMoVE to increase the scientific return in case of missed removal.
The progresses achieved by the developed algorithms can directly impact the design of the relative GNC systems of rendezvous missions (both devoted to ADR or to on-orbit-servicing). It is emphasised that, a large part of the results can be also exploited by other missions involving multiple satellites close to each other. Examples are the autonomous design of collision avoidance trajectories for formation flying missions or for satellites encountering debris in space.
Overall, the ReMoVE mission - intended as an ADR mission based on the use of the ReMoVE platform - introduces a new perspective in the architecture of removal missions. De facto, the ReMoVE satellite can be seen as an intelligent, autonomous, de-orbiting kit capable to reach by its own the target, to join it, and to “enhance” it. Accordingly, this mission philosophy differs from the classical de-orbiting kits attached to the target by a servicer satellite and differs from the standard approach of using a chaser satellite to capture a target object. ReMoVE could be seen as on-orbit-servicing applied to a debris removal mission.
The ReMoVE platform could be used to realise a multi-player and distributed ADR service for the LEO region. This would foresee to equip launchers by a ReMoVE platform in addition to their payloads. If a piece of debris can be reached in the following months (extremely likely to occur in LEO), it is then de-orbited, otherwise ReMoVE will re-enter not contributing to increase the number of objects in space. Secondary payloads might be embarked on ReMoVE to increase the scientific return in case of missed removal.