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Existing Internet protocols assume persistent end-to-end connectivity, which cannot be guaranteed in disruptive and high-latency space-terrestrial networks. To operate over these challenging networks, Delay/Disruption Tolerant Networking (DTN) architecture has been proposed. Although recent advances, evaluating DTN routing in large-scale networks spanning prolonged time-evolving topologies remain...
The design of a Compact Dual-band Equatorial helix antenna is presented. These antennas are used for Telemetry, Tracking, and Control (TTC) of satellites from the terrain base station. A simulation-optimization process is presented, a simulation tool named MONURBS is linked with a well-known multi-objective algorithm (NSGA-II) in order to design and optimize the parameters of the antenna. The size...
Solar Orbiter is a European Space Agency mission dedicated to Solar and Heliospheric Physics, currently planned for launch in February 2019. Due to its telemetry limitation, the mission planning should be carefully done to maximize scientific return. This work defines and simulates the scientific plan to address all sub-objectives under general Objective 3 of the Solar Orbiter mission: 'how do solar...
This paper presents the application of the Anisotropic Fast Marching Method to the path planning problem of robots moving in spatial environments. The slope of a terrain should be considered in a tensorial way because at any point on a mountainside there are two main slopes: the maximum, which is the slope of the gradient, and the minimum, which is the perpendicular slope to the gradient. The resulting...
In this paper we present an architecture that embeds an automatic task planner into the Robotic Operating System (ROS). The plans generated by the planner are automatically converted into executable behaviour trees. These behaviour trees are used as the basis of an execution monitoring process that is able to detect when the plan fails, trying to repair it or triggering a replanning process. This...
Either by resource-constrained communication systems, high signal propagation delay, or planet occlusion, space-terrestrial networks can neither expect a continuous nor instantaneous end-to-end connectivity. However, episodes of communications can be precisely computed based on orbital elements and then imprinted in contact plans to optimize Delay/Disruption Tolerant Networking (DTN) routing solutions...
Intelligent systems capabilities are increasing and its application to robotics has become largely popular. Some literature has been produced about autonomous controllers for robotics, demonstrating that they can face a variety of domains. However, we can observe that the experiments performed lack of a common scientific methodology. Generally, isolated case studies are presented, without providing...
In satellite on-board computers, memories are one of the components that need protection against radiation. Their effects can cause several types of errors like: Single Event Upsets (SEUs) that affect a bit of memory, Multiple-Cell Upsets (MCU), which corrupt several bits, and Single Event Functional Interrupt (SEFI) in control circuits, which can cause malfunction of the entire memory chip. This...
In this paper, an overview of a testing and simulation approach for a DTN protocol implementation (named µPCN) is provided. This implementation is intended to render low-cost world-wide satellite communication possible. It will be flighttested during the ESA OPS-SAT mission. To ensure its quality, a simulation environment has been developed used for testing its functionality in simulated LEO satellite...
Two GEO satellite anomalies have been related to electrostatic discharge during 1997 - 2010: Telstar 401 and Galaxy 15. This paper compares space weather conditions at the time of the anomaly for both events to check if there were similar conditions at the geospace that might increase risk of electrical discharge for surface and internal charging
The thermal subsystem of the Mars Express (MEX) orbiter keeps the on-board equipment within its pre-defined operating temperatures range. To plan and optimize the scientific operations of MEX, its operators need to estimate in advance, as accurately as possible, the power consumption of the thermal subsystem. The residual power can then be allocated for scientific purposes. We present a machine learning-based...
A machine learning approach for the operational situational awareness (OSA) in flight operations is presented. The spacecraft health and safety telemetry are generally time dependent and periodical. The machine learning algorithms, such as neural networks, are used to capture the time dependent trend of the telemetry datasets characterized by their data patterns and noise level, which provides a direct...
A novel way of extracting cellular automaton rules from a single automaton state is presented. The method, with minimal computation and storage, can be used to estimate rules to within approximately 5% on the class of density well cellular automata. Application of this method to image processing in the context of the search for life is then discussed. In particular the use of cellular automata as...
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