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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Autonomous onboard traverse science system

This paper provides a brief overview of the entire OASIS system and how it analyzes one type of data - grayscale images taken by the rover for engineering and hazard avoidance purposes.

OASIS↗
NASA NTRSDate not supplied

VIPER Mission Traverse Planning – Design, Strategies, and Dynamics

The Volatiles Investigation Polar Exploration Rover (VIPER) is a lunar polar volatiles prospecting mission developed through NASA’s Science Mission Directorate (SMD) Planetary Science Di-vision[1].VIPER is scheduled to land on Mons Mouton near the lunar South Pole in late 2024. VIPER’s primary mission goal is to characterize the distribution of water and volatiles across a range of thermal environments. This characterization aims to assist in understanding the origin of lunar polar volatiles and also help evaluate the In-Situ Resource Utilization (ISRU) potential of the lunar poles. The VIPER rover is a four-wheeled robotic vehicle weighing ~450 kg. It is solar-powered and teleoperated from Earth over a line-of-sight radio link. The rover can move at up to 20 cm/s on flat terrain. Accounting for commanding, localization, navigation, and obstacle-avoidance delays, however, the effective speed is closer to 1 cm/s. This effective speed is known as “Speed Made Good” (SMG), adopted from maritime culture, and kept as a key performance metric for VIPER oper-ations planning, execution, and evaluation. The mission duration is anticipated to be more than 90 Earth days and involves up to 20 km of driving. VIPER’s prospecting payload consists of spectrometers to detect volatiles and assess concentrations, context imagers, and a drill for sub-surface measurements down to one meter depth [2]. Mobility, combined with the prospecting and drill instrument suite, makes VIPER an analytically powerful resource mapper.

Volatiles Investigation Polar Exploration Rover (V↗
NASA NTRS2023

Petrological Traverse of the Olivine Cumulate Séítah Formation at Jezero Crater, Mars: A Perspective From SuperCam Onboard Perseverance

Séítah is the stratigraphically lowest formation visited by Perseverance in the Jezero crater floor. We present the data obtained by SuperCam: texture by imagery, chemistry by Laser-Induced Breakdown Spectroscopy, and mineralogy by Supercam Visible and Infrared reflectance and Raman spectroscopy. The Séítah formation consists of igneous, weakly altered rocks dominated by millimeter-sized grains of olivine with the presence of low-Ca and high-Ca pyroxenes, and other primary minerals (e.g., plagioclase, Cr-Fe-Ti oxides, phosphates). Along a ∼140 m long section in Séítah, SuperCam analyses showed evidence of geochemical and mineralogical variations, from the contact with the overlying Máaz formation, going deeper in the formation. Bulk rock and olivine Mg#, grain size, olivine content increase gradually further from the contact. Along the section, olivine Mg# is not in equilibrium with the bulk rock Mg#, indicating local olivine accumulation. These observations are consistent with Séítah being the deep ultramafic member of a cumulate series derived from the fractional crystallization and slow cooling of the parent magma at depth. Possible magmatic processes and exhumation mechanisms of Séítah are discussed. Séítah rocks show some affinity with some rocks at Gusev crater, and with some Martian meteorites suggesting that such rocks are not rare on the surface of Mars. Séítah is part of the Nili Fossae regional olivine-carbonate unit observed from orbit. Future exploration of Perseverance on the rim and outside of the crater will help determine if the observations from the crater floor can be extrapolated to the whole unit or if this unit is composed of distinct sub-units with various origins.

Mars 2020↗
NASA NTRSDate not supplied

Viper Science Operations: Science Traverse Planning Perspectives, Processes, and Tools.

Introduction: The NASA Volatiles Investigating Polar Exploration Rover (VIPER) launchesin late 2024 towards a landing site on Mons Mouton in the Nobile region of the Lunar South Pole (LSP). As described in other LPSC presentations [1,2,3], the primary objective of the VIPER mission is to study the composition and distribution of hydrogen-bearing and other volatiles by way of a complementary suite of payloads that the rover will carry to the Moon: three “prospecting” instruments which operate continuously while roving - the Neutron Spectrometer System (NSS), the Near InfraRed Volatiles Spectrometer System (NIRVSS), and the Mass Spectrometer observing lunar operations (MSolo). A 1-meter auguring/percussive drill called the The Regolith and Ice Drill for Exploration of New Terrains (TRIDENT) is used to bring subsurface cuttings to the surface in 10-cm increments where they are interrogated by NIRVSS and MSolo. The Visible Imaging System is comprised of eight cameras (the NavCam stereo pair mounted on the mast gimbal, the AftCam stereo pair mounted on the aft panel, and four HazCams mounted in the wheel wells) that capture grayscale visible wavelength images of the lunar environment and the rover’s upper deck. The VIPER mobility system is a four-wheel design that includes the following motorized modules: Suspension, Steering, and Drive/Propulsion. Wheel odometry and applied torque — combined with position data from rover imagery — can be used to compute assessments of ‘slip and sinkage’. Slope estimates can be computed from stereo rover imagery, as well as pitch and roll data from the IMU (Inertial Measurement Unit) and Star Tracker telemetry.

Darlene Sze Shien Lim↗
NASA NTRS1998

Rovers for Mars Polar Exploration

Mobility is a generic capability needed for Mars exploration. Requirements for mobility range from those to get observations of individual rocks all the way to getting high resolution observations of regional areas. Table 1 shows the required-range of mobility to achieve various tasks. The Pathfinder mission and field experiments simulating rover missions [1, 2, 3, 4, 5] provide guidance as to rover capabilities that can reasonably be expected in the next decade. Rover mobility can be accomplished in a variety of ways, the most common being wheels or tracks and legged-walkers. Wheeled vehicles can traverse over rocks smaller than 1/2 wheel diameter, and with path planning to avoid larger rocks, can traverse terrains comparable to those seen on Mars in the Viking and Pathfinder landing sites. Slopes of 45 deg can be easily negotiated by wheeled rovers. Walking vehicles can negotiate even more complex terrain but requires computation capability to select each leg placement. Extremely complex terrain was traversed by the Nomad II walker which descended into (and most of the way out of) an active volcanic caldera (Mount Spur, AK) in 1995, although a slope failure eventually resulted in broken legs. The traverse range of a rover is limited by its science objectives, performance capabilities, and operational lifetime. The speed of rover traverse is a relative minor factor. With a different communication system, and no stops for science experiments, Sojourner could probably have traveled a kilometer. But, achieving land speed records is not a major objective of a science mission. Achieving science objectives requires targeting particular objects and studying them in detail, and the associated operational requirements will likely limit rover traverse range significantly. Traversing from target to target requires relatively few command cycles provided the traverse is over a short enough distance that it can be adequately planned. An operational goal of 100 m traverse per command cycle, arriving at a predetermined target, seems achievable. Investigating science targets requiring manipulator or instrument placement and sample collection will likely take several command cycles per target. Mission simulations [6] have demonstrated that traverse dI stances of 100-300 m, with detailed investigation of 5-10 targets take 50-100 command cycles, not unlike the Pathfinder experience in spite of the use of larger, faster, more capable rovers. Significant advances in rover autonomy will be needed to improve this Situation and it is not clear how much improvement will be brought to flight programs in the next decade. Dust accumulation on solar panels degrades power over time and, without dust removal, rover operational lifetimes may be limited to 90 sols.

Stoker, Carol↗
NASA NTRS2009

Stereo Vision Based Terrain Mapping for Off-Road Autonomous Navigation

Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as no-go regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

passive perception↗