Space Robotics Part 2: Space-based Manipulators

In this second of three short papers, I introduce some of the basic concepts of space robotics with an emphasis on some specific challenging areas of research that are peculiar to the application of robotics to space infrastructure development. The style of these short papers is pedagogical and the concepts in this paper are developed from fundamental manipulator robotics. This second paper considers the application of space manipulators to on-orbit servicing (OOS), an application which has considerable commercial application. I provide some background to the notion of robotic on-orbit servicing and explore how manipulator control algorithms may be modified to accommodate space manipulators which operate in the micro-gravity of space

An approach to ground based space surveillance of geostationary on-orbit servicing operations

AbstractOn Orbit Servicing (OOS) is a class of dual-use robotic space missions that could potentially extend the life of orbiting satellites by fuel replenishment, repair, inspection, orbital maintenance or satellite repurposing, and possibly reduce the rate of space debris generation. OOS performed in geostationary orbit poses a unique challenge for the optical space surveillance community. Both satellites would be performing proximity operations in tight formation flight with separations less than 500m making atmospheric seeing (turbulence) a challenge to resolving a geostationary satellite pair when viewed from the ground. The two objects would appear merged in an image as the resolving power of the telescope and detector, coupled with atmospheric seeing, limits the ability to resolve the two objects. This poses an issue for obtaining orbital data for conjunction flight safety or, in matters pertaining to space security, inferring the intent and trajectory of an unexpected object perched very close to one׳s satellite asset on orbit. In order to overcome this problem speckle interferometry using a cross spectrum approach is examined as a means to optically resolve the client and servicer׳s relative positions to enable a means to perform relative orbit determination of the two spacecraft. This paper explores cases where client and servicing satellites are in unforced relative motion flight and examines the observability of the objects. Tools are described that exploit cross-spectrum speckle interferometry to (1) determine the presence of a secondary in the vicinity of the client satellite and (2) estimate the servicing satellite׳s motion relative to the client. Experimental observations performed with the Mont Mégantic 1.6m telescope on co-located geostationary satellites (acting as OOS proxy objects) are described. Apparent angular separations between Anik G1 and Anik F1R from 5 to 1 arcsec were observed as the two satellites appeared to graze one another. Data reduction using differential angular measurements derived from speckle images collected by the 1.6m telescope produced relative orbit estimates with better than 90m accuracy in the cross-track and in-track directions but exhibited highly variable behavior in the radial component from 50 to 1800m. Simulations of synthetic tracking data indicated that the radial component requires approximately six hours of tracking data for an Extended Kalman Filter to converge on an relative orbit estimate with less than 100m overall uncertainty. The cross-spectrum approach takes advantage of the Fast Fourier Transform (FFT) permitting near real-time estimation of the relative orbit of the two satellites. This also enables the use of relatively larger detector arrays (>106 pixels) helping to ease acquisition process to acquire optical angular data

How to build a biological machine using engineering materials and methods

We present work in 3D printing electric motors from basic materials as the key to building a self-replicating machine to colonise the Moon. First, we explore the nature of the biological realm to ascertain its essence, particularly in relation to the origin of life when the inanimate became animate. We take an expansive view of this to ascertain parallels between the biological and the manufactured worlds. Life must have emerged from the available raw material on Earth and, similarly, a self-replicating machine must exploit and leverage the available resources on the Moon. We then examine these lessons to explore the construction of a self-replicating machine using a universal constructor. It is through the universal constructor that the actuator emerges as critical. We propose that 3D printing constitutes an analogue of the biological ribosome and that 3D printing may constitute a universal construction mechanism. Following a description of our progress in 3D printing motors, we suggest that this engineering effort can inform biology, that motors are a key facet of living organisms and illustrate the importance of motors in biology viewed from the perspective of engineering (in the Feynman spirit of "what I cannot create, I cannot understand")

Training a terrain traversability classifier for a planetary rover through simulation

A classifier training methodology is presented for Kapvik, a micro-rover prototype. A simulated light detection and ranging scan is divided into a grid, with each cell having a variety of characteristics (such as number of points, point variance and mean height) which act as inputs to classification algorithms. The training step avoids the need for time-consuming and error-prone manual classification through the use of a simulation that provides training inputs and target outputs. This simulation generates various terrains that could be encountered by a planetary rover, including untraversable ones, in a random fashion. A sensor model for a three-dimensional light detection and ranging is used with ray tracing to generate realistic noisy three-dimensional point clouds where all points that belong to untraversable terrain are labelled explicitly. A neural network classifier and its training algorithm are presented, and the results of its output as well as other popular classifiers show high accuracy on test data sets after training. The network is then tested on outdoor data to confirm it can accurately classify real-world light detection and ranging data. The results show the network is able to identify terrain correctly, falsely classifying just 4.74% of untraversable terrain

Project MoonDust: Characterization and Mitigation of Lunar Dust

The feasibility of extended exploration and human presence on the Moon and Mars depends critically on dealing with the environmental factors, especially the intrusive effects of dust. The prior Apollo landed missions found that the lunar dust exhibited high adherence to exposed surfaces and a restrictive friction-like action causing premature wear of the EVA suits. MoonDust is a project being performed in collaboration with the Canadian Space Agency to study the effects of lunar dust on optics and mechanics, and to develop innovative solutions to extend their operational lifetime within a lunar or Mars environment based on the unique properties of carbon nanotube (CNT) nanocomposites. To assist this work, a small lunar environment simulation vacuum chamber has been set-up at MPB Communications to enable the study of lunar dust effects on optics and rotary mechanisms at pressures to below 10-5 Torr. New lunar dust simulants have been developed at the University of Winnipeg, characteristic of lunar Mare (UW-M1) and highland (UW-H1) compositions, that incorporate nanophase Fe in the silica particles. This paper describes the preliminary characterization of the various available lunar dust simulants that has included IR Raman for composition, Atomic Force and SEM Microscopy for morphology, and Vibrating Sample Magnetometer (VSM) for magnetic properties. Trial CNT dust deflectors/traps were fabricated and experimentally validated for magnetic and electrostatic interactions with lunar dust simulants. Good deflection and retention of submicron dust particles for device dust protection was observed. The preliminary experimental results are discussed

Crop Updates - 2003 Weeds

This session covers Thirty four papers from different authors INTRODUCTION INTEGRATED WEED MANAGEMENT IWM system studies/demonstration sites Six years of IWM investigation – what does it tell us? Bill Roy, Agricultural Consulting and Research Services Pty Ltd Long term herbicide resistance site, the final chapter, Peter Newman and Glen Adam, Department of Agriculture Management of skeleton weed (chondrilla juncea) in a cropping rotation in Western Australia, J. R. Peirce and B. J. Rayner, Department of Agriculture WEED BIOLOGY AND COMPETITION Annual ryegrass seedbanks: The good, the bad and the ugly, Kathryn J. Steadman1, Amanda J. Ellery2 and Sally C. Peltzer3 , 1WA Herbicide Resistance Initiative, UWA, 2CSIRO Plant Industry, 3 Department of Agriculture Annual ryegrass seeds after-ripen faster during a hot summer, Kathryn J. Steadman1, Gavin P. Bignell1 and Amanda J. Ellery2, 1WA Herbicide Resistance Initiative, UWA, 2CSIRO Plant Industry Predicting annual ryegrass dormancy from climatic variables, Amanda Ellery, Andrew Moore, Sandy Nedelkos, Ross Chapman, CSIRO Plant Industry Removing dormancy in annual ryegrass seeds for early herbicide resistance testing, Kathryn J. Steadman and Mechelle J. Owen, WA Herbicide Resistance Initiative, UWA Annual ryegrass germination responds to nitrogen, Amanda Ellery1, Simone Dudley1 and Robert Gallagher2, 1CSIRO Plant Industry, 2Washington State University The agro-ecology of Malva parviflora (small flowered mallow), Pippa J. Michael, Kathryn J. Steadman and Julie A. Plummer, Western Australia Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia The looming threat of wild radish, Peter Newman, Department of Agriculture IWM TOOLS Double knock, how close can we go? Peter Newman and Glen Adam, Department of Agriculture Double knock herbicide effect on annual ryegrass, Catherine Borger, Abul Hashem and Nerys Wilkins, Department of Agriculture Tactical techniques for managing Annual Ryegrass, Sally Peltzer1, Alex Douglas1, Fran Hoyle1, Paul Matson1 and Michael Walsh2 Department of Agriculture and 2Western Australian Herbicide Resistance Initiative. Weed control through soil inversion, Sally Peltzer, Alex Douglas and Paul Matson, Department of Agriculture The burning issues of annual ryegrass seed control, Darren Chitty and Michael Walsh, Western Australian Herbicide Resistance Initiative, UWA No sign of chaff-cart resistant ryegrass! David Ferris, WA Herbicide Resistance Initiative UWA PACKAGES AND MODELLING Conserving glyphosate susceptibility – modelling past, present and future us. Paul Neve1, Art Diggle2, Patrick Smith3 and Stephen Powles1 ,1Western Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, 2Department of Agriculture, 3CSIRO Sustainable Ecosystems WEEDEM: A program for predicting weed emergence in Western Australia, Michael Walsh,1 David Archer2, James Eklund2 and Frank Forcella2, 1Western Australia Herbicide Resistance Initiative, UWA, 2USDA-Agricultural Research Service, 803 Iowa Avenue, Morris, MN 56267, USA Weed and herbicide management for long term profit: A workshop, Alister Draper1 and Rick Llewellyn12, 1WA Herbicide Resistance Initiative, 2School of Agricultural and Resource Economics, University of Western Australia HERBICIDE RESISTANCE Alternative herbicides for control of triazine and diflufenican multiple resistant wild radish, Aik Cheam1, Siew Lee1, David Nicholson1 and Mike Clarke2 1Department of Agriculture, Western Australia, 2Bayer CropScience Resistance of wild mustard biotype to ALS-inhibiting herbicides in WA Wheatbelt, Abul Hashem, Department of Agriculture Glyphosate-resistant ryegrass biotypes in the WA wheatbelt, Abul Hashem, Catherine Borger and Nerys Wilkins, Department of Agriculture Implications of herbicide rates for resistance management, Paul Neve, Western Australian Herbicide Resistance Initiative, University of Western Australia Putting a price on herbicide resistance, Rick Llewellyn, School of Agricultural and Resource Economics/WA Herbicide Resistance Initiative, University of Western Australia Herbicide resistance from over the fence: Mobility and management, Debbie Allena, Rick Llewellynb, aUniversity of Western Australia, 4th year student, 2002. Mingenew-Irwin Group, bSchool of Agricultural and Resource Economics/Western Australia Herbicide Resistance Initiative, University of Western Australia HERBICIDE TOLERANCE Herbicide tolerance of new barley varieties, Harmohinder S. Dhammu and Terry Piper, Department of Agriculture Herbicide tolerance of new lupins, Harmohinder S. Dhammu, Terry Piper and David Nicholson, Department of Agriculture Herbicide tolerance of new field pea varieties, Harmohinder S. Dhammu, Terry Piper and David Nicholson, Department of Agriculture Herbicide tolerance of new lentil varieties, H.S. Dhammu, T.J. Piper and L.E. Young, Department of Agriculture HERBICIDES – NEW PRODUCTS/PRODUCT USES; USE Kill half leaf ryegrass with Spray.Seed® at night, Peter Newman and Glenn Adam, Department of Agriculture CLEARFIELD™ wheat to control hard-to-kill weeds, Abul Hashem, Catherine Borger and Nerys Wilkins, Department of Agriculture Diuron, a possible alternative to simazine pre-emergent in lupins, Peter Newman and Glenn Adam, Department of Agriculture Dual Gold® soft on barley, soft on weeds in dry conditions, Peter Newman and Glenn Adam, Department of Agriculture Dual Gold® soft on lupins, soft on ryegrass in dry conditions, Peter Newman and Glenn Adam, Department of Agricultur

Mars: new insights and unresolved questions

Mars exploration motivates the search for extraterrestrial life, the development of space technologies, and the design of human missions and habitations. Here, we seek new insights and pose unresolved questions relating to the natural history of Mars, habitability, robotic and human exploration, planetary protection, and the impacts on human society. Key observations and findings include: – high escape rates of early Mars’ atmosphere, including loss of water, impact present-day habitability; – putative fossils on Mars will likely be ambiguous biomarkers for life; – microbial contamination resulting from human habitation is unavoidable; and – based on Mars’ current planetary protection category, robotic payload(s) should characterize the local martian environment for any life-forms prior to human habitation.Some of the outstanding questions are:– which interpretation of the hemispheric dichotomy of the planet is correct; – to what degree did deep-penetrating faults transport subsurface liquids to Mars’ surface; – in what abundance are carbonates formed by atmospheric processes; – what properties of martian meteorites could be used to constrain their source locations; – the origin(s) of organic macromolecules; – was/is Mars inhabited; – how can missions designed to uncover microbial activity in the subsurface eliminate potential false positives caused by microbial contaminants from Earth; – how can we ensure that humans and microbes form a stable and benign biosphere; and – should humans relate to putative extraterrestrial life from a biocentric viewpoint (preservation of all biology), or anthropocentric viewpoint of expanding habitation of space?Studies of Mars’ evolution can shed light on the habitability of extrasolar planets. In addition, Mars exploration can drive future policy developments and confirm (or put into question) the feasibility and/or extent of human habitability of space