Validation of a Net Active Debris Removal Simulator within Parabolic Flight Experiment

Currently space debris is recognized as a major risk for space missions. In this frame it is involved the Patender project (Net parametric characterization and parabolic flight). The goal of this ESA funded activity (ending by March 2014) is to develop a confident mean to further investigate, develop and validate the concept of using nets for actively removing space debris of different characteristics. The net simulator will be validated in a parabolic flight experiment where microgravity conditions can be reached during some few tens of seconds. Different net shapes (pyramidal/planar) will be launched using a pneumatic-based dedicated mechanism in order to simulate the capture of a large space debris. High-speed motion cameras will record the experiment in order to allow the 3D reconstruction of the deployment and wrapping around the target phases and the validation of the software simulator

Application of the 0-1 test for chaos to experimental data

A reliable and efficient method to distinguish between chaotic and non-chaotic behaviour in noise-contaminated, but essentially stationary and deter-ministic, time series data has far reaching applications. Recently, we proposed a new method for detecting chaos which applies directly to the time series data and does not require phase space reconstruction. To illustrate the effectiveness of the method for experimental data, we analyse data from a bipolar motor. The standard technique to distinguish between regular and chaotic dynamics in deterministic time series data is to calculate the maximal Lyapunov exponent [1, 7, 14]. In the case of physical and biological applications, where the underlying dynamics is unknown, phase space reconstruction [1, 7, 16, 19, 18] is a necessary first step to compute Lyapunov exponents. However, there are problems inherent in phase space reconstruction as discussed in detail in [6, 17]. Recently, we proposed a new method [9] to detect chaos which applies directly to the time series data and does not require phase space reconstruction. Moreover, the dimension and origin of the dynamical system are irrelevant. The input is the time series data and the output is zero or one depending on whether the dynamics is non-chaotic or chaotic. This zero-one test for chaos is equally applicable to maps, ordinary and partial differential equations, and generally to data sets arising from deterministic systems. Of utmost importance is the effectiveness of the method for experimenta

Validation Results of Satellite Mock-Up Capturing Experiment Using Nets

The PATENDER activity (Net parametric characterization and parabolic flight), funded by the European Space Agency (ESA) via its Clean Space initiative, aims to validate a simulation tool for designing nets for capturing space debris. This validation will be performed through a set of different experiments under microgravity conditions. A net will be launched in order to capture a satellite mock-up. This paper presents the architecture of the thrown-net dynamics simulator together with the set-up of the deployment experiment and its preliminary results on a parabolic flight (Novcspace A-310, June 2015). The net dynamics has been modelled using lumped parameters method, where every string is discretized into lumped masses connected by springs and dampers: The ropes constitutive law is represented with linear Kelvin-Voigt model. A key aspect of the net deployment is to compute accurately the involved physics equations through a rigorous mathematical modelling. During the net wrapping phase it is needed to identify and manage the collisions arisen between the different elements. A collision detection engine is in charge of assessing the contact between the net and the target satellite. Contact dynamics has been implemented taking into account normal and tangential forces as result of the penetration depth and stiffness, damping and friction coefficients. The simulator is implemented within the Blender framework in order to provide a highly configurable tool, able to reproduce faithfully different scenarios for Active Debris Removal missions. The parabolic flight will allow performing thirty parabolas offering around 22s of zero-g conditions. Square nets will be launched at different initial velocities and launching angles using a pneumatic-based dedicated mechanism. High-speed motion cameras will record the experiment allowing 3D reconstruction of the net motion. The net knots have been coloured to allow the images post-process using colour segmentation, stereo matching and iterative closest point (ICP) for knots tracking. The final objective of the activity is the validation of the net deployment and wrapping simulator using acquired results during a parabolic flight. The parabolic flight images will be post-processed to generate the reference data for the simulator validation. The simulator will be properly configured according to the parabolic flight scenario, and executed in order to generate the validation data. The high speed camera images will be used to determine accurately the initial conditions

ANALOG-1 ISS - The first part of an analogue mission to guide ESA's robotic moon exploration efforts

The European Space Agency's ANALOG-1 experiment is the culmination of 12 distinct METERON experiments carried out since 2011. These all address aspects of teleoperating a robotic asset from an orbital platform, i.e., technical implementation, user interfaces, autonomy and operations. The ANALOG-1 technology demonstration and operations concept experiment is based upon the surface mission scenario segment of the notional EL3 sample return mission. This segment focuses on the control of a lunar surface robotic asset from the Earth and from the Lunar Gateway. The experiment is taking place in two parts, with the first successfully completed from the ISS in November 2019. It assessed the effectiveness of a state-of-the-art robotic control interface to control a complex mobile robot from orbit, as well as evaluating the scientific interactions, during robotic-assisted geology exploration, between crew in orbit and scientists on the ground. Luca Parmitano operated the robot while he was on the ISS. For this experiment, a complex control station had been installed on the ISS. The experiment demonstrated the advantage of having an immersive control station and high level of robotic dexterity, with Luca finishing all his assigned and secondary geology targets ahead of time

The Australian Square Kilometre Array Pathfinder: System Architecture and Specications of the Boolardy Engineering Test Array

This paper describes the system architecture of a newly constructed radio telescope - the Boolardy Engineer-ing Test Array, which is a prototype of the Australian Square Kilometre Array Pathnder telescope. Phasedarray feed technology is used to form multiple simultaneous beams per antenna, providing astronomerswith unprecedented survey speed. The test array described here is a 6-antenna interferometer, tted withprototype signal processing hardware capable of forming at least 9 dual-polarisation beams simultaneously,allowing several square degrees to be imaged in a single pointed observation. The main purpose of the testarray is to develop beamforming and wide-eld calibration methods for use with the full telescope, but itwill also be capable of limited early science demonstrations