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At least 433 records · Page 24

Strength and deformation properties of basaltic lava flows on planetary surfaces

Basaltic rocks are thought to constitute a volumetrically significant rock type on the Moon, Mercury, Mars, and Venus, in addition to the Earth. Spacecraft images of surfaces with known or suspected basaltic composition on these bodies, particularly on Venus, indicate that these rocks have been deformed in the brittle regime to form faults and perhaps dilatant cracks, in addition to folding and more distributed types of deformation. Predictions of brittle fracture or other types of deformation are made by comparing calculated stresses from a tectonic model to some criterion for rock strength. Common strength criteria used in the planetary science literature for near-surface deformation include a Griffith tensile-strength criterion for intact rock, a Mohr envelope for intact basalt, and a brittle strength envelope based on Byerlee's law of rock frictional resistance. However, planetary terrains of basaltic composition consist of much more than just intact basaltic rock. The aggregate basaltic material, termed the 'rock mass,' consists of both the intact rock and the associated fracture, faults, lithologic contacts, and other discontinuous surfaces. A basaltic rock mass is the relevant material for which strength properties must be defined and calculated model stresses must be compared to in order to more accurately predict brittle deformation. For example, the various strengths of a rock mass are less than that of intact material of the same composition. This means that tectonic models which compare stresses to intact failure strengths overestimate the stresses required for fracture and so underestimate the extent and magnitude of brittle deformation predicted in these models. On the other hand, rock mass shear strength can be greater than that predicted from Byerlee's law. The concept of rock mass strength is central to many engineering design studies in which calculated stresses are used to predict brittle fracture, and this experience indicates that brittle strength envelopes which assume properties for intact rock (Griffith parabolas) or sliding along a single, continuous surface (Byerlee's law) inadequately characterize the tensile, compressive, and shear strengths of rock masses. The criterion adopted here to relate stresses to rock mass fracture is based on a Griffith-type curve for tensile normal stress and a concave downward curve for compressive normal stress. It is the only available criterion that explicitly considers the weakening effects of discontinuities within the rock mass on the stress state required for fracture.

Schultz, Richard A.↗

New Retropropulsion Concept with NTAC Power for Mars Entry

Since the initial deployments of probes, orbiters, and rovers on Mars, there have been many ideas and concepts on how to perform an entry, descent, and landing (EDL) process efficiently and safely through the Martian atmosphere to place payloads onto the surface of Mars. Among the missions sent to perform EDL on Mars, only roughly sixty percent of the missions have been successful. The 5 minutes to 20 minutes of communication gap due to long-range telecommunications to Earth, described as seven minutes of terror, add to the complexity of EDL missions to Mars. As the payloads have become larger, the method of EDL has become more complex. To place an automobile-size science rover on the Martian surface requires the use of retrorockets mounted on a Sky Crane during the final subsonic stage of EDL. Larger payloads will require more propellant and more and/or larger retropropulsion engines during the earlier supersonic stage of EDL. The Sky Crane concept may not be scalable for these larger payloads and during supersonic flight; hence, new approaches are sought. A new power technology invented at NASA called Nuclear Thermionic Avalanche Cell (NTAC) may offer an additional solution. Powered by NTAC, the newly invented retropropulsion concept would ingest carbon dioxide gas, heat it up and blast it out as a new feature of the EDL process. NTAC would be reusable as a primary power source for payloads such as excavators, three-dimensional (3D) printers, or mobile equipment for mining, construction, and additive manufacturing tasks. Since NTAC would need to be landed with its host payload or as a standalone power package, assessing its ability to assist in its own EDL seems reasonable. The purpose of this Technical Memorandum (TM) is to examine the performance of NTAC in the context of EDL at Mars for motivating studies for integrating NTAC into future Mars mission architectures.

Mars entry↗

A Network Mission: Completing the Scientific Foundation for the Exploration of Mars

Despite recent setbacks and vacillations in the Mars Surveyor Program, in many respects the exploration of Mars has historically followed a relatively logical path. Early fly-bys provided brief glimpses of the planet and paved the way for the initial orbital reconnaissance of Mariner 9. The Viking orbiters completed the initial survey, while the Viking landers provided our first close-up look at the surface. Essentially, Mars Pathfinder served a similar role, giving a brief look at another place on the surface. And finally, Mars Global Surveyor (and the up-coming orbital mission in 2001) are taking the next step in providing in-depth, global observations of many of the fundamental characteristics of the planet, as well as selected high-resolution views of the surface. With this last step we are well on our way to acquiring the global scientific context that is necessary both for understanding Mars in general, its origin and evolution, and for use as a basis to plan and execute the next level of focused investigations. However, even with the successful completion of these missions this context will be incomplete. Whereas we now know a great deal about the surface of Mars in a global sense, we know very little about its interior, even at depths of only a meter or so. Also, as most of this information has been acquire by remote sensing, we still lack much of the bridging knowledge between the global view and the processes and character of the surface environments themselves. Thus, in many ways we lack sufficient fundamental understanding to intelligently cast the critical investigations into important questions of the origins and evolution of Mars in general, and in particular, life. The next step in building our understanding of Mars has been identified by several previous groups who were charged with creating a strategy for Mars exploration (e.g., COMPLEX, MarSWG, Planetary Roadmap Team). This is a so-called "network" mission, which places a large number of science platforms simultaneously on the surface.

W. B. Banerdt↗

Science Hybrid Orbiter and Lunar Relay (SCHOLR) Architecture and Design

Considered both a stepping-stone to deep space and a key to unlocking the mysteries of planetary formation, the Moon offers a unique opportunity for scientific study. Robotic precursor missions are being developed to improve technology and enable new approaches to exploration. Robots, lunar landers, and satellites play significant roles in advancing science and technologies, offering close range and in-situ observations. Science and exploration data gathered from these nodes and a lunar science satellite is intended to support future human expeditions and facilitate future utilization of lunar resources. To attain a global view of lunar science, the nodes will be distributed over the lunar surface, including locations on the far side of the Moon. Given that nodes on the lunar far side do not have direct line-of-sight for Earth communications, the planned presence of such nodes creates the need for a lunar communications relay satellite. Since the communications relay capability would only be required for a small portion of the satellite s orbit, it may be possible to include communication relay components on a science spacecraft. Furthermore, an integrated satellite has the potential to reduce lunar surface mission costs. A SCience Hybrid Orbiter and Lunar Relay (SCHOLR) is proposed to accomplish scientific goals while also supporting the communications needs of landers on the far side of the Moon. User needs and design drivers for the system were derived from the anticipated needs of future robotic and lander missions. Based on these drivers and user requirements, accommodations for communications payload aboard a science spacecraft were developed. A team of interns identified and compared possible SCHOLR architectures. The final SCHOLR architecture was analyzed in terms of orbiter lifetime, lunar surface coverage, size, mass, power, and communications data rates. This paper presents the driving requirements, operational concept, and architecture views for SCHOLR within a lunar surface nodal network. Orbital and bidirectional link analysis, between lunar nodes, orbiter, and Earth, as well as a conceptual design for the spacecraft are also presented

Trase, Kathryn K.↗

A Window in the Future of Planetary Surface Navigation

The presentation focuses on surface navigation and mapping challenges in planetary environments including Lunar and Martian surface. Imagery from precursor orbital missions are processed to provide a medium resolution, large coverage 2D and 3D maps used by the science and navigation teams. During the surface mission these mapping products together with the images captured from the on-board camera systems are used in rover localization and navigation.

planetary exploration↗

Challenges in Planetary Mapping and Surface Navigation

The presentation focuses on surface navigation and mapping challenges in planetary environments including Lunar and Martian surface. Imagery from precursor orbital missions are processed to provide a medium resolution, large coverage 2D and 3D maps used by the science and navigation teams. During the surface mission these mapping products together with the images captured from the on-board camera systems are used in rover localization and navigation.

planetary mapping↗

Comparison of Satellite Observations of Aerosol Optical Depth to Surface Monitor Fine Particle Concentration

Under NASA's Earth Science Applications Program, the Infusing satellite Data into Environmental Applications (IDEA) project examined the relationship between satellite observations and surface monitors of air pollutants to facilitate a more capable and integrated observing network. This report provides a comparison of satellite aerosol optical depth to surface monitor fine particle concentration observations for the month of September 2003 at more than 300 individual locations in the continental US. During September 2003, IDEA provided prototype, near real-time data-fusion products to the Environmental Protection Agency (EPA) directed toward improving the accuracy of EPA s next-day Air Quality Index (AQI) forecasts. Researchers from NASA Langley Research Center and EPA used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument combined with EPA ground network data to create a NASA-data-enhanced Forecast Tool. Air quality forecasters used this tool to prepare their forecasts of particle pollution, or particulate matter less than 2.5 microns in diameter (PM2.5), for the next-day AQI. The archived data provide a rich resource for further studies and analysis. The IDEA project uses data sets and models developed for tropospheric chemistry research to assist federal, state, and local agencies in making decisions concerning air quality management to protect public health.

Kleb, Mary M.↗

JETT3: A Holistic, Integrated Analog for Artemis Lunar Surface Exploration

Since 1972, NASA astronauts have performed hundreds of Extravehicular Activities (EVAs) in support of Skylab, Space Shuttle and International Space Station missions. Not since Apollo, however, have EVAs been driven by discovery-based principles of scientific exploration. Upcoming Artemis missions are challenged to build on lessons learned from Apollo, merging 50 years of EVA experience with the planetary science community’s expertise in the remote surface exploration of Mars. The highest-fidelity preparation for Artemis includes both operational and scientific underpinning to represent the complete, complex picture of lunar surface operations. The Joint EVA & Human Surface Mobility Test Team (JETT) is an interdisciplinary team providing such an environment for collaborative analog testing. JETT builds upon prior analog campaigns (e.g., [1, 2]) to provide high-fidelity environments for hardware and concept of operations development. Sponsored by the NASA EVA & Human Surface Mobility Program (EHP), JETT includes representatives from EHP, NASA Engineering, the Science Mission Directorate (SMD), Human Health & Performance, and the Flight Operations Directorate (FOD). JETT tests evaluate NASA reference designs for EVA (e.g., suits and tools), address gaps and risks for Artemis lunar surface operations, develop capabilities for EVA and science tasks, enable technology maturation, and provide training for Artemis EVA operations. JETT3, the final JETT field test of FY22, occurred Oct 3-11, 2022 in the San Francisco Volcanic Field north of Flagstaff, AZ. The test focused on developing the Artemis concept of operations and systems, including integrating an Artemis-like Science Team into a NASA Flight Control Team (FCT) to plan and execute a series of simulated lunar EVAs in an environment analogous to Artemis 3.

T. E. Caswell↗

JETT3: A Holistic, Integrated Analog for Artemis Lunar Surface Exploration

Since 1972, NASA astronauts have performed hundreds of Extravehicular Activities (EVAs) in support of Skylab, Space Shuttle and International Space Station missions. Not since Apollo, however, have EVAs been driven by discovery-based principles of scientific exploration. Upcoming Artemis missions are challenged to build on lessons learned from Apollo, merging 50 years of EVA experience with the planetary science community’s expertise in the remote surface exploration of Mars. The highest-fidelity preparation for Artemis includes both operational and scientific underpinning to represent the complete, complex picture of lunar surface operations. The Joint EVA & Human Surface Mobility Test Team (JETT) is an interdisciplinary team providing such an environment for collaborative analog testing. JETT builds upon prior analog campaigns (e.g., [1, 2]) to provide high-fidelity environments for hardware and concept of operations development. Sponsored by the NASA EVA & Human Surface Mobility Program (EHP), JETT includes representatives from EHP, NASA Engineering, the Science Mission Directorate (SMD), Human Health & Performance, and the Flight Operations Directorate (FOD). JETT tests evaluate NASA reference designs for EVA (e.g., suits and tools), address gaps and risks for Artemis lunar surface operations, develop capabilities for EVA and science tasks, enable technology maturation, and provide training for Artemis EVA operations. JETT3, the final JETT field test of FY22, occurred Oct 3-11, 2022 in the San Francisco Volcanic Field north of Flagstaff, AZ. The test focused on developing the Artemis concept of operations and systems, including integrating an Artemis-like Science Team into a NASA Flight Control Team (FCT) to plan and execute a series of simulated lunar EVAs in an environment analogous to Artemis 3.

T. E. Caswell↗

Mars Exploration Rover Surface Mission: Thermal Performance for More Than an Entire Martian Year

This viewgraph presentation reviews the thermal performance of the Mars Exploration Rovers. The Mars Exploration Rover (MER) project landed two identical roving science vehicles on Mars in January 2004; they have continued to perform geological science data collection well beyond their surface design lifetime of 90 sols. The design of the thermal system is described. Pictures from the rovers are also included,

flight performance↗

Lunar Mining and Processing: Considerations for Responsible Space Mining & Connections to Terrestrial Mining

The National Aeronautics and Space Administration (NASA) of the United States of America (US) has initiated the Artemis Moon to Mars program to send astronauts (the first woman and person of color) back to the lunar surface, create a sustainable human lunar exploration program, and lead the first human exploration mission to the Mars surface in the late 2030’s [1]. Besides reinvigorating human exploration beyond low Earth orbit not seen since the Apollo program and enabling new scientific activities and discoveries, a major objective of this program is to characterize the resources that exist on the Moon and Mars, and learn how to utilize them for human exploration and the commercialization of cis-lunar space. Commonly known as In Situ Resource Utilization (ISRU), the search for, acquisition, and processing of resources in space has the potential to greatly reduce the dependency on transporting mission consumables and infrastructure from Earth, thereby reducing mission costs, risks, and dependency on Earth. With the launch of Artemis I in November 2022 and the anticipation of several robotic missions to the Moon under the Commercial Lunar Payload Services (CLPS) program, greater recognition and excitement about NASA’s Artemis program and lunar exploration activities is growing in the public. With the recognition that past statements and concept videos of human exploration of the Moon are actually becoming real, there is also a growing awareness of the possible positive and negative consequences and impacts these exploration activities may have on the Moon and Mars. On the positive side, the development of ISRU and lunar mining and processing can enable and grow lunar surface exploration and cis-lunar commercial activities, as well as provide benefits to terrestrial industries through spin-in and spin-back of advanced technologies and autonomous operations. On the negative side, there is a perception that space mining will impact the lunar surface and environment negatively for science, and that cultural beliefs about the Moon need to be addressed and considered before these operations occur. This paper will begin to explore the potential driving attributes and guidelines that will address how best to maximize the lessons and connections to terrestrial mining to reduce the risk and cost of lunar ISRU and space commercial activities, enhance efforts to achieve the terrestrial ‘mine of the future’, and provide viable markets for space-derived technologies until commercial space mining is established. This paper will also begin to explore the potential driving attributes and guidelines that could address how to minimize the environmental and surface impacts of lunar ISRU and foster ‘responsible’ space mining that can be implemented until more official agreements and treaties are signed. The existing robust mining regulations adopted globally will be used as a basis for this examination and suggestions will be presented to adopt these agreements for use in space mining.

ISRU↗

The Project for Intercomparison of Land-surface Parameterization Schemes

The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) is described and the first stage science plan outlined. PILPS is a project designed to improve the parameterization of the continental surface, especially the hydrological, energy, momentum, and carbon exchanges with the atmosphere. The PILPS Science Plan incorporates enhanced documentation, comparison, and validation of continental surface parameterization schemes by community participation. Potential participants include code developers, code users, and those who can provide datasets for validation and who have expertise of value in this exercise. PILPS is an important activity because existing intercomparisons, although piecemeal, demonstrate that there are significant differences in the formulation of individual processes in the available land surface schemes. These differences are comparable to other recognized differences among current global climate models such as cloud and convection parameterizations. It is also clear that too few sensitivity studies have been undertaken with the result that there is not yet enough information to indicate which simplifications or omissions are important for the near-surface continental climate, hydrology, and biogeochemistry. PILPS emphasizes sensitivity studies with and intercomparisons of existing land surface codes and the development of areally extensive datasets for their testing and validation.

Henderson-Sellers, A.↗

The NASA Soil Moisture Active Passive (SMAP) Mission Formulation

The Soil Moisture Active Passive (SMAP) mission is one of the first-tier projects recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space. The SMAP mission is in formulation phase and it is scheduled for launch in 2014. The SMAP mission is designed to produce high-resolution and accurate global mapping of soil moisture and its freeze/thaw state using an instrument architecture that incorporates an L-band (1.26 GHz) radar and an L-band (1.41 GHz) radiometer. The simultaneous radar and radiometer measurements will be combined to derive global soil moisture mapping at 9 [km] resolution with a 2 to 3 days revisit and 0.04 [cm3 cm-3] (1 sigma) soil water content accuracy. The radar measurements also allow the binary detection of surface freeze/thaw state. The project science goals address in water, energy and carbon cycle science as well as provide improved capabilities in natural hazards applications.

microwave↗

Robotics Algorithms Provide Nutritional Guidelines

On July 5, 1997, a small robot emerged from its lander like an insect from an egg, crawling out onto the rocky surface of Mars. About the size of a child s wagon, NASA s Sojourner robot was the first successful rover mission to the Red Planet. For 83 sols (Martian days, typically about 40 minutes longer than Earth days), Sojourner - largely remote controlled by NASA operators on Earth - transmitted photos and data unlike any previously collected. Sojourner was perhaps the crowning achievement of the NASA Space Telerobotics Program, an Agency initiative designed to push the limits of robotics in space. Telerobotics - devices that merge the autonomy of robotics with the direct human control of teleoperators - was already a part of NASA s efforts; probes like the Viking landers that preceded Sojourner on Mars, for example, were telerobotic applications. The Space Telerobotics Program, a collaboration between Ames Research Center, Johnson Space Center, Jet Propulsion Laboratory (JPL), and multiple universities, focused on developing remote-controlled robotics for three main purposes: on-orbit assembly and servicing, science payload tending, and planetary surface robotics. The overarching goal was to create robots that could be guided to build structures in space, monitor scientific experiments, and, like Sojourner, scout distant planets in advance of human explorers. While telerobotics remains a significant aspect of NASA s efforts, as evidenced by the currently operating Spirit and Opportunity Mars rovers, the Hubble Space Telescope, and many others - the Space Telerobotics Program was dissolved and redistributed within the Agency the same year as Sojourner s success. The program produced a host of remarkable technologies and surprising inspirations, including one that is changing the way people eat

Source record↗

Mariner 9 mapping science sequence design.

The primary mission of Mariner 9 was to map the Martian surface. This paper discusses in detail the design of the mapping science sequences which were executed by the spacecraft in sixty days and during which over eighty percent of the surface was photographed. The sequence design was influenced by many factors: experimenter scientific objectives, instrument capabilities, spacecraft capabilities, orbit characteristics, and data return rates, which are illustrated graphically. Typical orbits are depicted for each of the three different mapping phases lasting twenty days. Examples of typical orbital sequence plans prepared daily during mission operations are given.

Goldman, A. M., Jr.↗

NASA’s Artemis Human Landing Systems: Enabling Lunar Exploration

On March 26, 2019, in keeping with Space Policy Directive-1, NASA was charged with landing the first woman and the next man on the South Pole of the Moon by 2024, followed by a sustained presence on and around the Moon by 2028. NASA’s Human Landing System (HLS) Program is responsible for the transportation in deep space to carry humans to and from the surface of the Moon, to be designed and developed by American companies for NASA’s Artemis lunar exploration program. On April 30, 2020, NASA announced the awardees for NASA’s Human Landing System contracts under Appendix H of the NextSTEP-2 Broad Agency Announcement: A Blue Origin-led team including Lockheed Martin, Northrup Grumman, and Draper; Dynetics (a Leidos company); and SpaceX. The companies began work in a multi-month base period during which NASA teams will work with the companies to streamline requirements, to establish standards and methods, to review required products and to share the NASA’s expertise in human spaceflight systems development. Following the base period, which ends in the spring of 2021, NASA will determine which company or companies will develop Artemis human landing systems for the initial demonstration missions, including the goal of landing on the Moon in 2024.This paper examines how the Human Landing System program is at the center of NASA’s Artemis lunar exploration program, designed to yield groundbreaking science, develop and utilize lunar surface resources and leverage the Moon as a proving ground for future Mars missions. While achieving the 2024 goal requires a focus on speed and the use of mature technologies, planning toward sustained operations to and from the lunar surface requires a focus on reliability and reusability.

Lisa Watson-Morgan↗

Venera-D Mission Concept to Study Atmosphere, Surface and Plasma Environment: Phase II Report of the Venera-D Joint Science Definition Team

Venus and Earth were formed approximately the same distance from the Sun, and have almost the same masses and volumes: they should be the most similar pair of planets in the Solar System. A vital, outstanding question is how and when these planets diverged in their atmospheric evolutions. Significantly, recent investigations present evidence for microbial life in Venus' cloud deck. Venus presents us with fundamental questions about the origin and evolution of planetary bodies and life in our Solar System.Venera-D (D stands for the Russian word for "long-lived:" dolgozhivushaya) is a potential mission that would combine simultaneous observations of Venus' atmosphere, plasma environment, and surface to try to answer these essential questions.

Zasova, L.↗

50,000 Laps Around Mars: Navigating the Mars Reconnaissance Orbiter Through the Extended Missions (January 2009 - March 2017)

Orbiting Mars since March 2006, the Mars Reconnaissance Orbiter (MRO) spacecraft continues to perform valuable science observations, provide telecommunication relay for surface assets, and characterize landing sites for future missions. Previous papers reported on the navigation of MRO from interplanetary cruise through the end of the Primary Science Phase (PSP) in December 2008 and on maneuvers performed through November 2016. This paper highlights the navigation of MRO from January 2009 through its 50,000th orbit around Mars on March 27, 2017, an eight-year period covering the Extended Science Phase, the first three extended missions, and a portion of the fourth extended mission which began on October 1, 2016. Since the beginning of the PSP in November 2006, MRO’s navigation performance has continued to exceed expectations. Over that period of time, the mission has returned over 300 terabytes of data.

Schulze, William↗