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Matthew Golombek - One of the best experts on this subject based on the ideXlab platform.
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Climate Change on Mars Inferred from Erosion Rates at the Mars Pathfinder Landing Site
1999Co-Authors: Matthew Golombek, N T BridgesAbstract:The observation that the Mars Pathfinder landing site probably looks very similar to when it was deposited by catastrophic floods some 1.8-3.5 Ga allows quantitative constraints to be placed on the rate of change at the landing site since that time. When combined with interpretations of data recently returned by the Mars Pathfinder and Global Surveyor missions and perspectives drawn from 20 years of analysis and interpretation of Viking data, these observations and inferences suggest an early warmer and wetter environment with vastly different erosion rates and a major climatic change on Mars. Additional information is contained in the original extended abstract.
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assessment of Mars Pathfinder landing site predictions
Journal of Geophysical Research, 1999Co-Authors: Matthew Golombek, H J Moore, A F C Haldemann, T J Parker, J T SchofieldAbstract:Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a rocky plain composed of materials deposited by catastrophic floods. The surface and observed maximum clast size appears similar to predictions based on an analogous surface of the Ephrata Fan in the Channeled Scabland of Washington state. The elevation of the site measured by relatively small footprint delay-Doppler radar is within 100 m of that determined by two-way ranging and Doppler tracking of the spacecraft. The nearly equal elevations of the Mars Pathfinder and Viking Lander 1 sites allowed a prediction of the atmospheric conditions with altitude (pressure, temperature, and winds) that were well within the entry, descent, and landing design margins. High-resolution (∼38 m/pixel) Viking Orbiter 1 images showed a sparsely cratered surface with small knobs with relatively low slopes, consistent with observations of these features from the lander. Measured rock abundance is within 10% of that expected from Viking orbiter thermal observations and models. The fractional area covered by large, potentially hazardous rocks observed is similar to that estimated from model rock distributions based on data from the Viking landing sites, Earth analog sites, and total rock abundance. The bulk and fine-component thermal inertias measured from orbit are similar to those calculated from the observed rock size-frequency distribution. A simple radar echo model based on the reflectivity of the soil (estimated from its bulk density), and the measured fraction of area covered by rocks was used to approximate the quasi-specular and diffuse components of the Earth-based radar echos. Color and albedo orbiter data were used to predict the relatively dust free or unweathered surface around the Pathfinder lander compared to the Viking landing sites. Comparisons with the experiences of selecting the Viking landing sites demonstrate the enormous benefit the Viking data and its analyses and models had on the successful predictions of the Pathfinder site. The Pathfinder experience demonstrates that, in certain locations, geologic processes observed in orbiter data can be used to infer surface characteristics where those processes dominate over other processes affecting the Martian surface layer.
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Mars Pathfinder landing site workshop 2 characteristics of the ares vallis region and field trips in the channeled scabland washington
1995Co-Authors: Matthew Golombek, K S Edgett, James W. RiceAbstract:Mars Pathfinder will place a single lander on the surface of Mars on July 4, 1997, following a December 1996 launch. As a result of the very successful first Mars Pathfinder Landing Site Workshop, the project has selected the Ares Vallis outflow channel in Chryse Planitia as the landing site. This location is where a large catastrophic outflow channel debouches into the northern lowlands. A second workshop and series of field trips, entitled Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington, were held in Spokane and Moses Lake, Washington. The purpose of the workshop was to provide a focus for learning as much as possible about the Ares Vallis region on Mars before landing there. The rationale is that the more that can be learned about the general area prior to landing, the better scientists will be able interpret the observations made by the lander and rover and place them in the proper geologic context. The field trip included overflights and surface investigations of the Channeled Scabland (an Earth analog for the martian catastrophic outflow channels), focusing on areas particularly analogous to Ares Vallis and the landing site. The overflights were essential for placing the enormous erosional and depositional features of the Channeled Scabland into proper three-dimensional context. The field trips were a joint educational outreach activity involving K-12 science educators, Mars Pathfinder scientists and engineers, and interested scientists from the Mars scientific community. Part 1 of the technical report on this workshop includes a description of the Mars Pathfinder mission, abstracts accepted for presentation at the workshop, an introduction to the Channeled Scabland, and field trip guides for the overflight and two field trips. This part, Part 2, includes the program for the workshop, summaries of the workshop technical sessions, a summary of the field trips and ensuing discussions, late abstracts of workshop presentations, reports on the education and public outreach activities carried out by the educators, and a list of the workshop and field trip participants.
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Mars Pathfinder Landing Site Workshop
1994Co-Authors: Matthew GolombekAbstract:The Mars Pathfinder Project is an approved Discovery-class mission that will place a lander and rover on the surface of the Red Planet in July 1997. The Mars Pathfinder Landing Site Workshop was designed to allow the Mars scientific community to provide input as to where to land Pathfinder on Mars. The workshop was attended by over 60 people from around the United States and from Europe. Over 20 landing sites were proposed at the workshop, and the scientific questions and problems concerning each were addressed. The workshop and the discussion that occured during and afterward have significantly improved the ability to select a scientifically exciting but safe landing site on Mars.
J T Schofield - One of the best experts on this subject based on the ideXlab platform.
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flight reconstruction of the Mars Pathfinder disk gap band parachute drag coefficients
Journal of Spacecraft and Rockets, 2005Co-Authors: Prasun N Desai, J T Schofield, Michael E LisanoAbstract:On July 4, 1997, the Mars Pathfinder (MPF) mission successfully landed on Mars. The entry, descent, and landing (EDL) scenario employed the use of a Disk-Gap-Band parachute design to decelerate the Lander. Flight reconstruction of the entry using MPF flight accelerometer data revealed that the MPF parachute decelerated faster than predicted. In the summer of 2003, the Mars Exploration Rover (MER) mission will send two Landers to the surface of Mars arriving in January 2004. The MER mission utilizes a similar EDL scenario and parachute design as that employed by MPF. As a result, characterizing the degree of underperformance of the MPF parachute system is critical for the MER EDL trajectory design. This paper provides an overview of the methodology utilized to estimate the MPF parachute drag coefficient as experienced on Mars.
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assessment of Mars Pathfinder landing site predictions
Journal of Geophysical Research, 1999Co-Authors: Matthew Golombek, H J Moore, A F C Haldemann, T J Parker, J T SchofieldAbstract:Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a rocky plain composed of materials deposited by catastrophic floods. The surface and observed maximum clast size appears similar to predictions based on an analogous surface of the Ephrata Fan in the Channeled Scabland of Washington state. The elevation of the site measured by relatively small footprint delay-Doppler radar is within 100 m of that determined by two-way ranging and Doppler tracking of the spacecraft. The nearly equal elevations of the Mars Pathfinder and Viking Lander 1 sites allowed a prediction of the atmospheric conditions with altitude (pressure, temperature, and winds) that were well within the entry, descent, and landing design margins. High-resolution (∼38 m/pixel) Viking Orbiter 1 images showed a sparsely cratered surface with small knobs with relatively low slopes, consistent with observations of these features from the lander. Measured rock abundance is within 10% of that expected from Viking orbiter thermal observations and models. The fractional area covered by large, potentially hazardous rocks observed is similar to that estimated from model rock distributions based on data from the Viking landing sites, Earth analog sites, and total rock abundance. The bulk and fine-component thermal inertias measured from orbit are similar to those calculated from the observed rock size-frequency distribution. A simple radar echo model based on the reflectivity of the soil (estimated from its bulk density), and the measured fraction of area covered by rocks was used to approximate the quasi-specular and diffuse components of the Earth-based radar echos. Color and albedo orbiter data were used to predict the relatively dust free or unweathered surface around the Pathfinder lander compared to the Viking landing sites. Comparisons with the experiences of selecting the Viking landing sites demonstrate the enormous benefit the Viking data and its analyses and models had on the successful predictions of the Pathfinder site. The Pathfinder experience demonstrates that, in certain locations, geologic processes observed in orbiter data can be used to infer surface characteristics where those processes dominate over other processes affecting the Martian surface layer.
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results of the Mars Pathfinder atmospheric structure investigation
Journal of Geophysical Research, 1999Co-Authors: Julio A Magalhaes, J T Schofield, Alvin SeiffAbstract:We report on a thorough analysis of the Mars Pathfinder atmospheric structure investigation (ASI) accelerometer data spanning the altitude range 161–8.9 km. Entry, descent, and landing occurred within 850 km of the Viking 1 lander and somewhat later in northern summer. The early morning entry (0300 hours) provided the first opportunity to study Mars' nighttime atmospheric structure; the close proximity to the Viking 1 site has permitted a search for changes in atmospheric structure during the 21 years between the landings. Our results confirm and refine the major features of the atmospheric structure discovered in the initial analysis of the ASI results reported by Schofield et al. [1997]. The current analysis has yielded a much better definition of the temperature structure above 90 km altitude. Pathfinder measured a thermospheric peak temperature of 153°K at 134 km, which is 30°K colder than the value found by Viking 1. Between 110 and 88 km, Pathfinder found a broad, nearly isothermal plateau at 127°K, which correlates very well with a similar structure evident in Viking 1 data at the same pressures, although the Pathfinder layer is 25°K colder. At levels above 88 km, wavelike oscillations with a wavelength ∼5 km and amplitudes of 2–3°K are evident, possibly reflecting gravity or planetary wave activity. Between 90 and 60 km the average temperature is 20–30°K cooler than Viking 1 values. Large-amplitude (10–20°K) long-wavelength (20–40 km) oscillations, which show a remarkable correspondence to equivalent structures found in the Viking 1 profile at the same pressures, occur in this region and are likely due to a diurnal tidal mode. Between 85 and 77 km a minimum of one oscillation results in temperatures up to 7°K below the saturation temperature of CO2, well outside the uncertainties in the measurements and the vapor pressure curve and comparable to observed supersaturations of water in Earth's mesosphere. Between 55 and 16 km, temperatures are close to or warmer than Viking 1 values; superposed long-wavelength oscillations correspond well with similar structures observed by Viking 1. Between 16 and 9.9 km the temperature profile shows an unexpected strong thermal inversion, which may reflect radiative cooling due to a water cloud. At the base of the inversion, temperatures begin to increase abruptly until the last measurement at 8.9 km. The Viking-like temperatures in the lower atmosphere are consistent with the Viking-like dust optical depths observed by the Mars Pathfinder imager. The cool temperatures in the middle and upper atmosphere may be indicative of significant nighttime cooling at these levels, although other interpretations are possible.
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the Mars Pathfinder atmospheric structure investigation meteorology asi met experiment
Science, 1997Co-Authors: J T Schofield, James R. Murphy, Robert M. Haberle, Alvin Seiff, Jeffrey R Barnes, D Crisp, Soren Ejling Larsen, Julio A Magalhaes, G. R. WilsonAbstract:The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment measured the vertical density, pressure, and temperature structure of the martian atmosphere from the surface to 160 km, and monitored surface meteorology and climate for 83 sols (1 sol = 1 martian day = 24.7 hours). The atmospheric structure and the weather record are similar to those observed by the Viking 1 lander (VL-1) at the same latitude, altitude, and season 21 years ago, but there are differences related to diurnal effects and the surface properties of the landing site. These include a cold nighttime upper atmosphere; atmospheric temperatures that are 10 to 12 degrees kelvin warmer near the surface; light slope-controlled winds; and dust devils, identified by their pressure, wind, and temperature signatures. The results are consistent with the warm, moderately dusty atmosphere seen by VL-1.
J R Hall - One of the best experts on this subject based on the ideXlab platform.
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processing and analysis of Mars Pathfinder science data at the jet propulsion laboratory s science data processing systems section
Journal of Geophysical Research, 1999Co-Authors: S. K. Lavoie, Allan J. Runkle, Elizabeth D. Duxbury, W. B. Green, D Alexander, P Andres, E M Dejong, David J Freda, Zareh Gorjian, J R HallAbstract:The Mars Pathfinder mission required new capabilities and adaptation of existing capabilities in order to support science analysis and flight operations requirements imposed by the in situ nature of the mission. The Science Data Processing Systems Section of the Jet Propulsion Laboratory was responsible for the design, development, and application of the system required to perform telemetry processing, distribution, and archiving of data from the four primary science instruments, and support of flight operations through production of automatically generated stereo and color mosaics, terrain visualizations, and animations. The system developed for Mars Pathfinder incorporated new capabilities in producing computer-generated color mosaics, for cataloging and distribution of science data, and utilized new display technology to support science analysis and flight operations requirements. This paper describes the data processing performed to support the science and operations payload on the Pathfinder lander and Sojourner rover.
Matthew P. Golombek - One of the best experts on this subject based on the ideXlab platform.
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Introduction to the special section: Mars Pathfinder
Journal of Geophysical Research, 1999Co-Authors: Matthew P. GolombekAbstract:Mars Pathfinder successfully landed on the surface of Mars on July 4, 1997, ushering in a renewed phase of exploration of our neighboring world after a hiatus of over 20 years. In addition to successfully capturing the imagination of the public by landing a robust, low-cost spacecraft and rover on the Red Planet, Pathfinder returned a significant volume of scientific data. Pathfinder was the first Mars mission to use a rover, which carried a chemical analysis instrument that characterized the rocks and soils in a landing area occupying hundreds of square meters. In 3 months of surface operations at Ares Vallis, Pathfinder's three science instruments, 10 technology experiments, and engineering subsystems aboard the rover and lander, addressed seven general areas of scientific investigations.
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the Mars Pathfinder mission
Scientific American, 1998Co-Authors: Matthew P. GolombekAbstract:Mars Pathfinder, one of the first Discovery-class missions (quick, low-cost projects with focused science objectives), will land a single spacecraft with a microrover and several instruments on the surface of Mars in 1997. Pathfinder will be the first mission to use a rover, carrying a chemical analysis instrument, to characterize the rocks and soils in a landing area over hundreds of square meters on Mars, which will provide a calibration point or "ground truth" for orbital remote sensing observations. In addition to the rover, which also performs a number of technology experiments, Pathfinder carries three science instruments: a stereoscopic imager with spectral filters on an extendable mast, an alpha proton X ray spectrometer, and an atmospheric structure instrument/meteorology package. The instruments, the rover technology experiments, and the telemetry system will allow investigations of the surface morphology and geology at submeter to a hundred meters scale, the petrology and geochemistry of rocks and soils, the magnetic properties of dust, soil mechanics and properties, a variety of atmospheric investigations, and the rotational and orbital dynamics of Mars. Landing downstream from the mouth of a giant catastrophic outflow channel, Ares Vallis at 19.5 deg N, 32.8 deg W, offers the potential of identifying and analyzing a wide variety of crustal materials, from the ancient heavily cratered terrain, intermediate-aged ridged plains, and reworked channel deposits, thus allowing first-order scientific investigations of the early differentiation and evolution of the crust, the development of weathering products, and tile early environments and conditions on Mars.
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overview of the Mars Pathfinder mission and assessment of landing site predictions
Science, 1997Co-Authors: Matthew P. Golombek, H J Moore, A F C Haldemann, J M Knudsen, Richard A. Cook, W M Folkner, T Economou, P H Kallemeyn, R M Manning, T J ParkerAbstract:Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than ∼1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free.
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the Mars Pathfinder mission
Journal of Geophysical Research, 1997Co-Authors: Matthew P. GolombekAbstract:Mars Pathfinder, one of the first Discovery-class missions (quick, low-cost projects with focused science objectives), will land a single spacecraft with a microrover and several instruments on the surface of Mars in 1997. Pathfinder will be the first mission to use a rover, carrying a chemical analysis instrument, to characterize the rocks and soils in a landing area over hundreds of square meters on Mars, which will provide a calibration point or “ground truth” for orbital remote sensing observations. In addition to the rover, which also performs a number of technology experiments, Pathfinder carries three science instruments: a stereoscopic imager with spectral filters on an extendable mast, an alpha proton X ray spectrometer, and an atmospheric structure instrument/meteorology package. The instruments, the rover technology experiments, and the telemetry system will allow investigations of the surface morphology and geology at submeter to a hundred meters scale, the petrology and geochemistry of rocks and soils, the magnetic properties of dust, soil mechanics and properties, a variety of atmospheric investigations, and the rotational and orbital dynamics of Mars. Landing downstream from the mouth of a giant catastrophic outflow channel, Ares Vallis at 19.5°N, 32.8°W, offers the potential of identifying and analyzing a wide variety of crustal materials, from the ancient heavily cratered terrain, intermediate-aged ridged plains, and reworked channel deposits, thus allowing first-order scientific investigations of the early differentiation and evolution of the crust, the development of weathering products, and the early environments and conditions on Mars.
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Scientists, educators prepare for Mars Pathfinder mission
Eos Transactions American Geophysical Union, 1996Co-Authors: Kenneth S. Edgett, James W. Rice, Matthew P. GolombekAbstract:Mars scientists, engineers, and 13 K-12 educators invaded eastern Washington's Channeled Scabland for a week in September to explore terrain similar to the kind Mars Pathfinder will encounter when it touches down on the red planet on July 4, 1997. Through field trips and workshops, the scientists and engineers reached consensus on a number of issues about Mars history and shared their knowledge and enthusiasm with the public. The teachers, who came from Washington and Idaho, witnessed engineering, scientific investigation, and debate in action, and acquired a great deal of knowledge about Mars that they can bring back to their classrooms and communities. “We worked side by side with the scientists and engineers as they researched, experimented, problem-solved and debated different aspects of the Mars Pathfinder mission,” explained high school teacher John Gallagher.
Ronald Greeley - One of the best experts on this subject based on the ideXlab platform.
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aeolian features and processes at the Mars Pathfinder landing site
Journal of Geophysical Research, 1999Co-Authors: Ronald Greeley, Ruslan O. Kuzmin, N T Bridges, Kenneth E Herkenhoff, M D Kraft, Robert Sullivan, Gregory Wilson, Michael C Malin, W WardAbstract:The Mars Pathfinder landing site contains abundant features attributed to aeolian, or wind, processes. These include wind tails, drift deposits, duneforms of various types, ripplelike features, and ventifacts (the first clearly seen on Mars). Many of these features are consistant with formation involving sand-size particles. Although some features, such as dunes, could develop from saltating sand-size aggregates of finer grains, the discovery of ventifact flutes cut in rocks strongly suggests that at least some of the grains are crystalline, rather than aggregates. Excluding the ventifacts, the orientations of the wind-related features correlate well with the orientations of bright wind steaks seen on Viking Orbiter images in the general area. They also correlate with wind direction predictions from the NASA-Ames General Circulation Model (GCM) which show that the strongest winds in the area occur in the northern hemisphere winter and are directed toward 209°.
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results from the Mars Pathfinder camera
Science, 1997Co-Authors: P H Smith, Daniel T. Britt, Ronald Greeley, James F. Bell, N T Bridges, L R Gaddis, H U Keller, Kenneth E Herkenhoff, R Jaumann, Jeffrey R. JohnsonAbstract:Images of the martian surface returned by the Imager for Mars Pathfinder (IMP) show a complex surface of ridges and troughs covered by rocks that have been transported and modified by fluvial, aeolian, and impact processes. Analysis of the spectral signatures in the scene (at 440- to 1000-nanometer wavelength) reveal three types of rock and four classes of soil. Upward-looking IMP images of the predawn sky show thin, bluish clouds that probably represent water ice forming on local atmospheric haze (opacity ∼0.5). Haze particles are about 1 micrometer in radius and the water vapor column abundance is about 10 precipitable micrometers.
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Potential landing sites for Mars Pathfinder
1994Co-Authors: Ruslan O. Kuzmin, R. Landheim, Ronald GreeleyAbstract:In addition to a better understanding of the geological evolution of Mars, new techniques for processing available data have emerged, new data have been acquired, and the engineering approaches for placing spacecraft on the surface have evolved. Selection of the Mars Pathfinder landing site must take these issues into account, along with mission constraints. An advantage of Mars Pathfinder is the rover for sampling surface materials over a range of tens of meters. However, engineering constraints and the limited scientific payload of this mission require new approaches for landing site selection. One approach is to select sites exhibiting a wide variety of rocks near the lander. An alternative approach is to select sites in which the regional geology consists of a single rock type representing a key datum for the geological study of Mars, and is uniformly distributed within the landing ellipse.