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Bearing-Only Navigation for Proximity Operations on Cis-Lunar Non-Keplerian Orbits
Full text linkIn the next years many scientific and demonstration missions will target the cislunar environment to consolidate existing technologies and foster the development of new space systems to support a future human exploration of Mars. Among those, the Lunar Orbital Platform Gateway (LOP-G) will operate as a long-term modular infrastructure in deep-space, offering services to both manned and unmanned missions to the Moon. To safely accomplish many of its tasks, rendezvous and docking/undocking operations must be reliably performed on highly non-Keplerian orbits. However, despite rendezvous and relative navigation are well-known for Earth-centred missions, no autonomous proximity operation has ever been performed in the cislunar domain. Within this framework, the paper assesses the applicability of Bearing-Only measurements to perform relative navigation between distant heterogeneous non-Keplerian orbits. Starting from the absolute motion, a useful discrete-time approximation of the non-Keplerian relative dynamics is presented to support the development of a computationally efficient Guidance, Navigation and Control (GNC) architecture based on a Shrinking Horizon - Model Predictive Control (SH-MPC) strategy. The outcomes of two different test scenarios are critically discussed to prove the effectiveness of the proposed method and highlight potential solutions that enhance the filter observability with minimum fuel consumption
Bearing-Only Navigation to Support Proximity Operations on Cislunar Non-Keplerian Orbits
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No full textCislunar distributed architectures for communication and navigation services of lunar assets
Full text linkThe last decade saw a renewed interest on the Moon as a well suited training premise in preparation to manned mission to Mars, but also as an interesting target itself, for scientific investigations, technological developments and new markets opportunities. As a result, numerous and very different missions to the Moon are currently being studied and implemented, assuming to have our satellite quite crowded soon. Such a scenario motivates the settling of space infrastructures to offer recurrent services like data relays, communication links and navigation in the cislunar environment which would facilitate and enlighten the single mission's implementation and operation. The paper presents the strategy adopted to address the design of the orbital configuration for a distributed architecture to answer the communication and navigation needs to serve at the best the diversified lunar missions scenario expected for the next decades. First, a set of parameters of merit are identified and explained in their mathematical expression and physical meaning. Then, different regions of interest for possible future missions are identified and mapped to the relevant performances wanted for that specific region. Last a Multi-Objective Optimisation framework is presented, both in the exploited genotype and the different objectives participating to the definition of the cost function, in order to provide a versatile tool. The paper critically discusses the effectiveness of the proposed approach in detecting the best suited distributed orbital architectures for the servicers according to the expected service performance in specific user regions, spread all over the Earth–Moon volume — from Earth vicinity to Lunar surface, considering also robustness aspects. The benefits in the exploitation of the multibody dynamical regime offered by the Earth–Moon system to set up the most promising orbital set with a minimum number of servicing spacecraft are underlined as well
Cislunar Distributed Architectures for Communication and Navigation Services of Lunar Assets
Full text linkThe last decade saw a renewed interest on the Moon as a well suited training premise in preparation to manned mission to Mars, but also as an interesting target itself, for scientific investigations, technological developments and new markets opportunities. As a result, numerous and very different missions to the Moon are currently being studied and implemented, assuming to have our satellite quite crowded soon. Such a scenario motivates the settling of space infrastructures to offer recurrent services like data relays, communication links and navigation in the cislunar environment which would facilitate and enlighten the single mission's implementation and operation. The paper presents the strategy adopted to address the design of the orbital configuration for a distributed architecture to answer the communication and navigation needs to serve at the best the diversified lunar missions scenario expected for the next decades. First, a set of parameters of merit are identified and explained in their mathematical expression and physical meaning. Then, different regions of interest for possible future missions are identified and mapped to the relevant performances wanted for that specific region. Last a Multi-Objective Optimisation framework is presented, both in the exploited genotype and the different objectives participating to the definition of the cost function, in order to provide a versatile tool. The paper critically discusses the effectiveness of the proposed approach in detecting the best suited distributed orbital architectures for the servicers according to the expected service performance in specific user regions, spread all over the Earth-Moon volume - from Earth vicinity to Lunar surface, considering also robustness aspects. The benefits in the exploitation of the multibody dynamical regime offered by the Earth-Moon system to set up the most promising orbital set with a minimum number of servicing spacecraft are underlined as well
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