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The precise mechanism for the formation and evolution of crater valley networks in the Martian southern highlands remains under debate, with precipitation, groundwater flow, and melting induced by impact being suggested. We studie...
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The precise mechanism for the formation and evolution of crater valley networks in the Martian southern highlands remains under debate, with precipitation, groundwater flow, and melting induced by impact being suggested. We studied valley networks within four craters of the Noachis Terra highlands that were representative of similar features in Noachis Terra and where orbital data existed for analysis in order to characterise their morphology and infer possible processes involved in their formation and evolution. We found evidence for valleys carved by liquid water and ice-related processes. This included strong evidence of liquid water-based valley formation through melting of ice-rich deposits throughout our study area, suggesting an alternative to previously suggested rainfall or groundwater-based scenarios. The location of these valleys on steeply sloping crater walls, as opposed to the shallow slopes of the highlands where Martian valleys are typically found, suggested that our 'fluvial' valleys had not evolved a more structured fluvial morphology as valley networks found on the Martian plains. Our studied valleys' association with ice-rich material and abundant evidence for erosion caused by downslope flow of ice-rich material are consistent with a cold, wet Mars hypothesis where accumulation, flow, and melting of ice have been dominant factors in eroding crater valleys. Additionally, analysis of valley morphology with slope and aspect suggested a greater dependence on local geology and presence of volatiles than larger valley networks, though ice-related valleys were consistently wider for their length than valleys assessed as fluvial carved. We assessed that local conditions such as climate, geology, and availability of ice-rich material played a major role in the erosion of crater valleys at our study site. (C) 2016 Elsevier B.V. All rights reserved.
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Recent advances in low-cost microprocessors and sensors have allowed for the development of low-cost spectrometers for public experimentation and education outreach. In the context of the present paper and other recent research, l...
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Recent advances in low-cost microprocessors and sensors have allowed for the development of low-cost spectrometers for public experimentation and education outreach. In the context of the present paper and other recent research, low-cost spectrometers are important remote sensing instruments for numerous applications in citizen science and education. We built five spectrometer designs then tested them for absorption using concentrations of fluids and reflectance using colour swatches and minerals found on Mars as well as other materials possessing a high near infra-red (NIR) reflectance. These results were then compared with a laboratory grade spectrometer. We found that while all spectrometers produced meaningful results during the fluid concentration tests, there were considerable differences in accuracies between home-made instruments during the reflectance testing. Two spectrometer designs were identified that produced useful results for a range of low-cost scientific applications.
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The ability to access, design and create low cost sensors capable of returning scientifically useful data has led to an exponential increase in citizen science, education and environmental monitoring groups. Low-cost spectroscopy ...
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The ability to access, design and create low cost sensors capable of returning scientifically useful data has led to an exponential increase in citizen science, education and environmental monitoring groups. Low-cost spectroscopy is one such application and mobile phone camera-based instruments have been used in pollution monitoring, medical applications in developing countries and vegetation analysis. Can such an instrument be developed and tested to assist with automated detection of materials, possibly from space? We tested two spectrometer designs inside a two unit (2U) cubesat frame against a series of materials exhibiting phenomenology in the visible/near infrared (Vis/NIR) portion of the spectrum and vegetation groups. This was conducted in order to determine whether open source designs were capable of discriminating against similar materials, such as types of vegetation or types of iron-rich minerals. A spectral pipeline was created using open source programming software that was capable of converting raw sensor data into spectra, comparing samples of interest against a spectral library and returning an identification result with a confidence interval. We found that low-cost hardware sensitive to NIR and freely available software were able to identify types of materials in the study set, enabling applications in citizen science, education and outreach or even low-cost near-space research.
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Astronauts working on the surface of Mars have the capability to explore efficiently, rapidly, and flexibly, allowing them to perform a wide range of field investigations. NASA has begun an open international process to identify a...
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Astronauts working on the surface of Mars have the capability to explore efficiently, rapidly, and flexibly, allowing them to perform a wide range of field investigations. NASA has begun an open international process to identify and evaluate candidate locations where crews could land, live and work on the martian surface, beginning with the First Landing Site/Exploration Zone Workshop for Human Missions to the Surface of Mars in October 2015. Forty seven sites were proposed, including several at or near the Meridiani area, the subject of this paper. We consider the Meridiani area an excellent candidate for the first missions to Mars. It is accessible, safe, contains potential water resources in the form of poly-hydrated magnesium sulphates, has diverse science features with high likelihood of meeting all science goals, has other potential resources and potential for further longer-ranged exploration. The presence of hardware from previous missions will be of benefit to studies of materials to martian conditions, assessing the effectiveness of historic planetary protection strategies, and engaging public interest. Lastly, parts of the Meridiani region have been well studied from the surface by the Opportunity mission, providing ground truth for orbital data. As one of the best documented regions of Mars this will allow a "Go where you know" approach for the first crewed missions, especially with regard to safety, trafficability, and water resource potential.
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We assessed robotic performance by performing Structure from Motion (SfM) mapping surveys of a small gully in New South Wales, Australia, using two rovers of different sizes that each captured photographic images from a high-resol...
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We assessed robotic performance by performing Structure from Motion (SfM) mapping surveys of a small gully in New South Wales, Australia, using two rovers of different sizes that each captured photographic images from a high-resolution, 12 megapixel (MP) camera and a low-resolution (<1 MP) camera. Results from these trials were compared with a simulated unmanned aerial vehicle (UAV) SfM survey of the same gully feature using the high-resolution camera on a boom pole. We conducted this in order to determine whether small, ground-based vehicles would be suitable remote-sensing platforms for collecting this data where UAV operations would be impractical or impossible. Accuracy of the resulting point clouds and the time taken to complete the surveys were used as the key metrics to assess the performance of the respective methods. The high-resolution camera surveys produced digital elevation models (DEMs) that corresponded closely to the control points surveyed using Real Time Kinematic (RTK) global positioning system (GPS) technology, although the robotic surveys took longer to complete. Additionally, camera resolution and height above ground were the major factors when determining the success of generating SfM data. We found that despite these limitations, ground-based vehicles are capable of generating point clouds accurate enough to be used to investigate small-scale geomorphology.
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Comparison of the similarities and differences between terrestrial and Martian hillside gullies promotes understanding of how surface processes operate on both planets. Here we tested the viability of subsurface flow of water as a...
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Comparison of the similarities and differences between terrestrial and Martian hillside gullies promotes understanding of how surface processes operate on both planets. Here we tested the viability of subsurface flow of water as a process affecting gully evolution. We compared gullies within the Monaro Volcanic Province near Cooma, New South Wales, Australia, to gullies possessing strong structural control near Gasa Crater, Terra Cimmeria, Mars. Although cursory examination of the Monaro gullies initially suggested strong evidence for aquifer erosion, detailed field surveys showed the evidence to be ambiguous. Instead a complex regime of erosion dependent on multiple conditions and processes such as local geology, surface runoff, dry mass wasting, and animal activity emerged. We found the morphology of gullies near Gasa Crater to be consistent with erosion caused by liquid water, while also being heavily influenced by the local environment, including slope and geology. Additionally, erosion at the Martian site was not consistent with evidence of subsequent, smaller scale erosion and channel modification by dry mass wasting. Local conditions thus play an important role in gully evolution, further highlighting that processes forming Martian gullies may be more diverse than initially thought. (C) 2015 Elsevier B.V. All rights reserved.
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The precise mechanisms by which martian hillside gullies erode and their dependence on the local environment remain subjects of debate. We studied three sharp rimmed craters in Noachis Terra and 37 gully profiles using Context Cam...
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The precise mechanisms by which martian hillside gullies erode and their dependence on the local environment remain subjects of debate. We studied three sharp rimmed craters in Noachis Terra and 37 gully profiles using Context Camera (CTX), Mars Orbiter Laser Altimeter (MOLA) and High Resolution Stereo Camera (HRSC) data. We analysed the gully topographic profiles of seven gullies and nine dry ravines. We measured slope properties using HRSC elevation data and used thermal inertia to infer material types of the gully sites. We compared these with three nearby Noachian age craters possessing crater wall slope angles within the range of previously observed gully formations. In-line with previous findings on individual gullies, we found that the slope angles of gullies in our study area consistently reflect the inherited slope angles of the host escarpment, suggesting that traditional slope-based evidence of fluvial activity in martian gullies needs to be placed in context of its local environment. We also observed a direct relationship between gully morphology and local composition of surface units. Martian gully features, and possibly method of erosion appeared heavily influenced by changes in underlying geology and presence of erodible sediment. Examples included gully shape changing in accordance with type of erodible sediment. We suggest that the degraded rims of gully-free Noachian craters precluded slope angles high enough to trigger creation of precursors to alcoves through mass wasting. Lack of these hollows has probably prevented the accumulation of enough ice-rich sediment for gullies to form in. Our analysis reveals that there is a complex interdependence between slope processes and the local environment, and global martian gully models may not work at the local scale. (C) 2014 Elsevier Inc. All rights reserved.
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Open source, low cost sensors, and robotic systems have developed to the point of being able to produce meaningful, repeatable results in real-life applications. We developed a low-cost, open source multispectral camera mounted on...
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Open source, low cost sensors, and robotic systems have developed to the point of being able to produce meaningful, repeatable results in real-life applications. We developed a low-cost, open source multispectral camera mounted on a small custom-built robotic rover. We compared the performance of our camera with a commercial multispectral camera and a laboratory spectrometer using minerals commonly found on Mars that exhibited different reflectance values in visible and near-infrared wavelengths. Our camera performed favourably when compared to the commercial instruments. It is a very cost effective solution for operating in extreme situations, where damage to instruments is possible. Our total system of rover and sensor would, therefore, be very useful for operating in delicate and inaccessible environments where damage to the area under investigation and to human observers is of concern.
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Although Martian gullies resemble terrestrial counterparts, two conflicting hypotheses exist for their formation still invoke fluvial processes on the one hand or lubricated CO2 flows on the other. In this work we compared the qua...
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Although Martian gullies resemble terrestrial counterparts, two conflicting hypotheses exist for their formation still invoke fluvial processes on the one hand or lubricated CO2 flows on the other. In this work we compared the quantitative morphology of terrestrial gullies, known to have formed by liquid water, and mid-latitude Martian gullies in the Martian southern hemisphere. We also compared these results with measurements of Martian dry ravines adjacent to the gullies. Our results show a similarity between Martian and terrestrial gully formation, supporting the hypothesis that liquid water was involved in their erosion. Our results show dry ravines differ morphologically from gullies, further suggesting fluidised flows as a likely origin of the latter. Variations in the relationships across various terrestrial and Martian gullies indicate the significance of local environmental and geological conditions. Our work supports the idea that Martian gullies may not have been formed by just one single process but may have evolved through a more complex interaction of processes and environment. (C) 2017 Elsevier B.V. All rights reserved.
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