Resilient Perception for Outdoor Unmanned Ground Vehicles

This thesis promotes the development of resilience for perception systems with a focus on Unmanned Ground Vehicles (UGVs) in adverse environmental conditions. Perception is the interpretation of sensor data to produce a representation of the environment that is necessary for subsequent decision making. Long-term autonomy requires perception systems that correctly function in unusual but realistic conditions that will eventually occur during extended missions. State-of-the-art UGV systems can fail when the sensor data are beyond the operational capacity of the perception models. The key to resilient perception system lies in the use of multiple sensor modalities and the pre-selection of appropriate sensor data to minimise the chance of failure. This thesis proposes a framework based on diagnostic principles to evaluate and preselect sensor data prior to interpretation by the perception system. Image-based quality metrics are explored and evaluated experimentally using infrared (IR) and visual cameras onboard a UGV in the presence of smoke and airborne dust. A novel quality metric, Spatial Entropy (SE), is introduced and evaluated. The proposed framework is applied to a state-of-the-art Visual-SLAM algorithm combining visual and IR imaging as a real-world example. An extensive experimental evaluation demonstrates that the framework allows for camera-based localisation that is resilient to a range of low-visibility conditions when compared to other methods that use a single sensor or combine sensor data without selection. The proposed framework allows for a resilient localisation in adverse conditions using image data but also has significant potential to benefit many perception applications. Employing multiple sensing modalities along with pre-selection of appropriate data is a powerful method to create resilient perception systems by anticipating and mitigating errors. The development of such resilient perception systems is a requirement for next-generation outdoor UGVs

Workshop on Mars Sample Return Science

Martian magnetic history; quarantine issues; surface modifying processes; climate and atmosphere; sampling sites and strategies; and life sciences were among the topics discussed

Foundations of space biology and medicine. Volume 1: Space as a habitat

Cosmological aspects of the universe are discussed in relation to exobiological research in the context of modern biochemistry and biophysics

Manned Mars Mission. Working group papers, volume 2, section 5 - appendix

Topics discussed include: science investigations and issues; life science/medical issues; subsystems and technology development requirements; political issues; and impacts on other programs

The atmospheric entry of micrometeorites on Mars: Implications for their mineralogy, texture and organic constituents

The nature of martian micrometeorites (MMs) was investigated in this thesis through micro-analysis of terrestrial MMs and computational and experimental simulations of atmospheric entry heating. The biases in the Larkman Nunatak micrometeorite collection revealed in this study (Chapter 3) are attributed to the strong winnowing effects associated with sediment transport by aeolian processes. The weathering features observed in these micrometeorites are related to interaction with transient water. Sediment transport on Mars is dominated by aeolian processes, thus accumulations are likely to be similar to wind driven collections on Earth. However, their weathering state is expected to differ from terrestrial micrometeorites owing to the lack of water and much longer accumulation periods and is instead thought to be dominated by perchlorate induced oxidation. Computational simulations of atmospheric entry (Chapter 4) suggest much greater quantities of large, low temperature micrometeorites reaching the martian surface. The lower temperatures and larger particles surviving on Mars are likely to aid in the preservation of micrometeorite derived organic material with large portions of the micrometeorite flux expected to remain below the sublimation temperature of some organic compounds and larger particles allowing thermal gradients to form within particles. Experimental simulations (Chapter 5) indicate several differences between terrestrial and martian particles. Iron oxide phases were lacking in the martian particles including a magnetite rim, which is observed in the severely heated terrestrial particles. Additionally, sulphur and phosphorus are preserved in much greater quantities and in reduced forms in the martian particles. Raman spectroscopy also revealed that micrometeorite derived organic material on Earth experience greater evolution through the expansion of sp2 cluster diameter and growth of aromatic ring structures. Most of these features can be attributed to oxidative processes. Thus, atmospheric composition is thought to be a controlling factor in the nature micrometeorite derived organic material reaching a planetary surface.Open Acces

Habitability on Early Mars and the Search for Biosignatures with the ExoMars Rover

Finally, we would like to recognize the help and support of ESA, Roscosmos, the European states and agencies participating in the ExoMars program, and NASA. We really are doing this together for the benefit of all.The second ExoMars mission will be launched in 2020 to target an ancient location interpreted to have strong potential for past habitability and for preserving physical and chemical biosignatures (as well as abiotic/prebiotic organics). The mission will deliver a lander with instruments for atmospheric and geophysical investigations and a rover tasked with searching for signs of extinct life. The ExoMars rover will be equipped with a drill to collect material from outcrops and at depth down to 2 m. This subsurface sampling capability will provide the best chance yet to gain access to chemical biosignatures. Using the powerful Pasteur payload instruments, the ExoMars science team will conduct a holistic search for traces of life and seek corroborating geological context information.European Space AgencyRoscosmosExoMars programNational Aeronautics & Space Administration (NASA

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 401)

This bibliography lists 140 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during May 1995. Subject coverage includes: aerospace medicine, behavioral sciences, man/system technology and life support, and space biology

Alfvén waves underlying ionospheric destabilization: ground-based observations

During geomagnetic storms, terawatts of power in the million mile-per-hour solar wind pierce the Earth’s magnetosphere. Geomagnetic storms and substorms create transverse magnetic waves known as Alfvén waves. In the auroral acceleration region, Alfvén waves accelerate electrons up to one-tenth the speed of light via wave-particle interactions. These inertial Alfvén wave (IAW) accelerated electrons are imbued with sub-100 meter structure perpendicular to geomagnetic field B. The IAW electric field parallel to B accelerates electrons up to about 10 keV along B. The IAW dispersion relation quantifies the precipitating electron striation observed with high-speed cameras as spatiotemporally dynamic fine structured aurora. A network of tightly synchronized tomographic auroral observatories using model based iterative reconstruction (MBIR) techniques were developed in this dissertation. The TRANSCAR electron penetration model creates a basis set of monoenergetic electron beam eigenprofiles of auroral volume emission rate for the given location and ionospheric conditions. Each eigenprofile consists of nearly 200 broadband line spectra modulated by atmospheric attenuation, bandstop filter and imager quantum efficiency. The L-BFGS-B minimization routine combined with sub-pixel registered electron multiplying CCD video stream at order 10 ms cadence yields estimates of electron differential number flux at the top of the ionosphere. Our automatic data curation algorithm reduces one terabyte/camera/day into accurate MBIR-processed estimates of IAW-driven electron precipitation microstructure. This computer vision structured auroral discrimination algorithm was developed using a multiscale dual-camera system observing a 175 km and 14 km swath of sky simultaneously. This collective behavior algorithm exploits the “swarm” behavior of aurora, detectable even as video SNR approaches zero. A modified version of the algorithm is applied to topside ionospheric radar at Mars and broadcast FM passive radar. The fusion of data from coherent radar backscatter and optical data at order 10 ms cadence confirms and further quantifies the relation of strong Langmuir turbulence and streaming plasma upflows in the ionosphere with the finest spatiotemporal auroral dynamics associated with IAW acceleration. The software programs developed in this dissertation solve the century-old problem of automatically discriminating finely structured aurora from other forms and pushes the observational wave-particle science frontiers forward

Publications of the Jet Propulsion Laboratory, 1978

This bibliography cites 958 externally distributed technical papers released during calendar year 1978, that resulted from scientific and engineering work performed, or managed, by the Jet Propulsion Laboratory. The publications are indexed by author, subject, publication type and number. A descriptive entry appears under the name of each author of each publication; an abstract is included with the entry for the primary (first-listed) author

Reports of planetary geology program, 1979 - 1980

Abstracts of 145 reports are compiled addressing the morphology, geochemistry, and stratigraphy of planetary surfaces with some specific examinations of volcanic, aeolian, fluvial, and periglacial processes and landforms. In addition, reports on cartography and remote sensing of planet surfaces are included