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At least 811 records · Page 45

Exploring Mars

This presentation shows what researchers are designing (solar balloon and rover) to better explore Mars geography before sending a manned mission.

Source record↗

JOVE NASA-FIT program: Microgravity and aeronomy projects

This semi-annual status report is divided into two sections: Scanning Tunneling Microscopy Lab and Aeronomy Lab. The Scanning Tunneling Microscopy (STM) research involves studying solar cell materials using the STM built at Florida Tech using a portion of our initial Jove equipment funding. One result of the participation in the FSEC project will be to design and build an STM system which is portable. This could serve as a prototype STM system which might be used on the Space Shuttle during a Spacelab mission, or onboard the proposed Space Station. The scanning tunneling microscope is only able to image the surface structure of electrically conductive crystals; by building an atomic force microscope (AFM) the surface structure of any sample, regardless of its conductivity, will be able to be imaged. With regards to the Aeronomy Lab, a total of four different mesospheric oxygen emission codes were created to calculate the intensity along the line of sight of the shuttle observations for 2972A, Herzberg I, Herzberg II, and Chamberlain bands. The thermosphere-ionosphere coupling project was completed with two major accomplishments: collection of 500 data points on modulation of neutral wind with geophysical variables, and establishment of constraints on behavior of the height of the ionosphere as a result of interaction between geophysical and geometrical factors. The magnetotail plasma project has been centered around familiarization with the subject in the form of a literature search and preprocessing of IMP-8 data.

Patterson, James D.↗

Physics of magnetospheric boundary layers

This final report was concerned with the ideas that: (1) magnetospheric boundary layers link disparate regions of the magnetosphere-solar wind system together; and (2) global behavior of the magnetosphere can be understood only by understanding its internal linking mechanisms and those with the solar wind. The research project involved simultaneous research on the global-, meso-, and micro-scale physics of the magnetosphere and its boundary layers, which included the bow shock, the magnetosheath, the plasma sheet boundary layer, and the ionosphere. Analytic, numerical, and simulation projects were performed on these subjects, as well as comparisons of theoretical results with observational data. Other related activity included in the research included: (1) prediction of geomagnetic activity; (2) global MHD (magnetohydrodynamic) simulations; (3) Alfven resonance heating; and (4) Critical Ionization Velocity (CIV) effect. In the appendixes are list of personnel involved, list of papers published; and reprints or photocopies of papers produced for this report.

Cairns, Iver H.↗

Venus 2000 Mission Design

As part of the Discovery Program, National Aeronautics and Space Administration (NASA) has solicited proposals for inter-planetary research to conduct solar system exploration science investigations. A mission, called Venus 2000 (V2k), has been proposed for exploration of the Venus Atmosphere. This is NASAs first voyage to Venus to investigate key science objectives since Magellan and will be launched in summer 2002. In keeping with discovery program requirements to reduce total mission cost and utilize new technology, V2k mission design and control will focus on the use of innovative and proven trajectory analysis programs and control systems provided by the Goddard Space Flight Center (GSFC).

Folta, David↗

Magnetic Characteristics of Active Region Heating Observed with TRACE, SOHO/EIT, and Yohkoh/SXT

Over the past several years, we have reported results from studies that have compared the magnetic structure and heating of the transition region and corona (both in active regions and in the quiet Sun) by combining X-ray and EUV images from Yohkoh and Solar and Heliospheric Observatory (SOHO) with photospheric magnetograms from ground-based observatories. Our findings have led us to the hypothesis that most heating throughout the corona is driven from near and below the base of the corona by eruptive microflares occurring in compact low-lying "core magnetic fields (i.e., fields rooted along and closely enveloping polarity inversion lines in the photospheric magnetic flux). We now extend these studies, comparing sequences of UV images from Transition Region and Coronal Explorer (TRACE) with longitudinal magnetograms from Kitt Peak and vector magnetograms from MUSIC. These comparisons confirm the previous results regarding the importance of core-field activity to active region heating. Activity in fields associated with satellite polarity inclusions and/or magnetically sheared configurations is especially prominent. This work is funded by NASA's Office of Space Science through the Sun-Earth Connection Guest Investigator Program and the Solar Physics Supporting Research and Technology Program.

Porter, J. G.↗

Prediction of Coronal Mass Ejections From Vector Magnetograms: Quantitative Measures as Predictors

We derived two quantitative measures of an active region's global nonpotentiality from the region's vector magnetogram, 1) the net current (I(sub N)), and 2) the length of strong-shear, strong-field main neutral line (Lss), and used these two measures in a pilot study of the CME productivity of 4 active regions. We compared the global nonpotentiality measures to the active regions' CME productivity determined from GOES and Yohkoh/SXT observations. We found that two of the active regions were highly globally nonpotential and were CME productive, while the other two active regions had little global nonpotentiality and produced no CMEs. At the Fall 2000 AGU, we reported on an expanded study (12 active regions and 17 magnetograms) in which we evaluated four quantitative global measures of an active region's magnetic field and compared these measures with the CME productivity. The four global measures (all derived from MSFC vector magnetograms) included our two previous measures (I(sub N) and L(sub ss)) as well as two new ones, the total magnetic flux (PHI) (a measure of an active region's size), and the normalized twist (alpha (bar)= muIN/PHI). We found that the three quantitative measures of global nonpotentiality (I(sub N), L(sub ss), alpha (bar)) were all well correlated (greater than 99% confidence level) with an active region's CME productivity within plus or minus 2 days of the day of the magnetogram. We will now report on our findings of how good our quantitative measures are as predictors of active-region CME productivity, using only CMEs that occurred after the magnetogram. We report the preliminary skill test of these quantitative measures as predictors. We compare the CME prediction success of our quantitative measures to the CME prediction success based on an active region's past CME productivity. We examine the cases of the handful of false positive and false negatives to look for improvements to our predictors. This work is funded by NSF through the Space Weather Program and by NASA through the Solar Physics Supporting Research and Technology Program.

Falconer, D. A.↗

Coronal Heating and the Magnetic Flux Content of the Network

Previously, from analysis of SOHO/EIT coronal images in combination with Kitt Peak magnetograms (Falconer et al 1998, ApJ, 501, 386-396), we found that the quiet corona is the sum of two components: the e-scale corona and the coronal network. The large-scale corona consists of all coronal-temperature (T approx. 10(exp 6) K) structures larger than supergranules (>approx.30,000 km). The coronal network (1) consists of all coronal-temperature structures smaller than supergranules, (2) is rooted in and loosely traces the photospheric magnetic network, (3) has its brightest features seated on polarity dividing fines (neutral lines) in the network magnetic flux, and (4) produces only about 5% of the total coronal emission in quiet regions. The heating of the coronal network is apparently magnetic in origin. Here, from analysis of EIT coronal images of quiet regions in combination with magnetograms of the same quiet regions from SOHO/MDI and from Kitt Peak, we examine the other 95% of the quiet corona and its relation to the underlying magnetic network. We find: (1) Dividing the large-scale corona into its bright and dim halves divides the area into bright "continents" and dark "oceans" having spans of 2-4 supergranules. (2) These patterns are also present in the photospheric magnetograms: the network is stronger under the bright half and weaker under the dim half. (3) The radiation from the large-scale corona increases roughly as the cube root of the magnetic flux content of the underlying magnetic network. In contrast, Fisher et A (1998, ApJ, 508, 985-998) found that the coronal radiation from an active region increases roughly linearly with the magnetic flux content of the active region. We assume, as is widely held, that nearly all of the large-scale corona is magnetically rooted in the network. Our results, together with the result of Fisher et al (1999), suggest that either the coronal heating in quiet regions has a large non-magnetic component, or, if the heating is predominantly produced via the magnetic field, the mechanism is significantly different than in active regions. This work is funded by NASA's Office of Space Science through the Solar Physics Supporting Research and Technology Program and the Sun-Earth Connection Guest Investigator Program.

Falconer, D. A.↗

Use of Yohkoh SXT in Measuring the Net Current and CME Productivity of Active Regions

In our investigation of the correlation of global nonpotentiality of active regions to their CME productivity (Falconer, D.A. 2001, JGR, in press, and Falconer, Moore, & Gary, 2000, EOS 82, 20 S323), we use Yohkoh SXT images for two purposes. The first use is to help resolve the 180 degree ambiguity in the direction of the observed transverse magnetic field. Resolution of the 180 degree ambiguity is important, since the net current, one of our measures of global nonpotentiality, is derived from integrating the dot product of the transverse field around a contour (I(sub N)=(integral)BT(raised dot)dl). The ambiguity results from the observed transverse field being determined from the linear polarization, which gives the plane of the direction, but leaves a 180 degrees ambiguity. Automated methods to resolve the ambiguity ranging from the simple acute angle rule (Falconer, D.A. 2001) to the more sophisticated annealing method (Metcalf T.R. 1994). For many active regions, especially ones that are nearly potential these methods work well. But for very nonpotential active regions where the shear angle (the angle between the observed and potential transverse field) is near 90 degrees throughout large swaths along the main neutral line, both methods can resolve the ambiguity incorrectly for long segments of the neutral line. By determining from coronal images, such as those from Yohkoh/SXT, the sense of shear along the main neutral line in the active region, these cases can be identified and corrected by a modification of the acute angle rule described here. The second use of Yohkoh/SXT in this study is to check for the cusped coronal arcades of long-duration eruptive flares. This signature is an excellent proxy for CMEs, and was used by Canfield, Hudson, and McKenzie (1999 GRL V26, 6, 627-630). This work is funded by NSF through the Space Weather Program and by NASA through the Solar Physics Supporting Research and Technology Program.

Falconer, D. A.↗

Contagious Coronal Heating from Recurring Emergence of Magnetic Flux

For each of six old bipolar active regions, we present and interpret Yohkoh/SXT and SOHO/MDI observations of the development, over several days, of enhanced coronal heating in and around the old bipole in response to new magnetic flux emerge= within the old bipole. The observations show: 1. In each active region, new flux emerges in the equatorward side of the old bipole, around a lone remaining leading sunspot and/or on the equatorward end of the neutral line of the old bipole. 2. The emerging field is marked by intense internal coronal heating, and enhanced coronal heating occurs in extended loops stemming from the emergence site. 3. In five of the six cases, a "rooster tail" of coronal loops in the poleward extent of the old bipole also brightens in response to the flux emergence. 4. There are episodes of enhanced coronal heating in surrounding magnetic fields that are contiguous with the old bipole but are not directly connected to the emerging field. From these observations, we suggest that the accommodation of localized newly emerged flux within an old active region entails far reaching adjustments in the 3D magnetic field throughout the active region and in surrounding fields in which the active region is embedded, and that these adjustments produce the extensive enhanced coronal heating. We also note that the reason for the recurrence of flux emergence in old active regions may be that active region flux tends to emerge in giant-cell convection downflows. If so, the poleward "rooster tail" is a coronal flag of a long-lasting downflow in the convection zone. This work was funded by NASA's Office of Space Science through the Solar Physics Supporting Research and Technology Program and the Sun-Earth Connection Guest Investigator Program.

Moore, Ronald L.↗

Measurement Scale of the SOLIS Vector Spectromagnetograph

Longitudinal magnetograms obtained with thc SOLIS Vector Spectromagnetograph (VSM) during a cross-calibration period are compared with similar data from the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope as well as with SOHO/MDI and GONG magnetogram. The VSM began observation at the University of Arizona agricultural test site and collaborative observations were obtained with both the VSM and SPM from 2003 Aug 05 through 2003 Sep 21 where the SPM was officially retired. The VSM replaces the SPM and continues the 3O-year NSO/Kitt Peak synoptic magnetogram record. Magnetograms are compared by equating histograms and, for selected examples, by pixel-by-pixel comparison of co-registered images. The VSM was not corrected for polarization crosstalk and was operated without hast guiding. Solar activity was at best moderate during this period. Over the range of observed fields, the VSM magnetograms show greatly improved sensitivity but are otherwise virtually identical with "raw" SPM magnetogram. GONG magnetograms are also closely comparable with the SPM while MDI flux values tend to be stronger by a factor of 1.2 - 1.4. Dependence of the results on seeing will be discussed. Partial funding for this work was provided through Solar and Heliospheric Research Supporting Research and Technology grants from NASA's Office of Space Sciences.

Jones, Harrison P.↗

SAMPIE Measurements of the Space Station Plasma Current Analyzed

In March of 1994, STS-62 carried the NASA Lewis Research Center's Solar Array Module Plasma Interactions Experiment (SAMPIE) into orbit, where it investigated the plasma current collected and the arcs from solar arrays and other space power materials immersed in the low-Earth-orbit space plasma. One of the important experiments conducted was the plasma current collected by a four-cell coupon sample of solar array cells for the international space station. The importance of this experiment dates back to the 1990 and 1991 meetings of the Space Station Electrical Grounding Tiger Team. The Tiger Team determined that unless the electrical potentials on the space station structure were actively controlled via a plasma contactor, the space station structure would arc into the plasma at a rate that would destroy the thermal properties of its surface coatings in only a few years of operation. The space station plasma contactor will control its potentials by emitting electrons into the surrounding low-Earth-orbit plasma at the same rate that they are collected by the solar arrays. Thus, the level at which the space station solar arrays can collect current is very important in verifying that the plasma contactor design can do its job.

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Laser Ranging to the Moon, Mars and Beyond

Current and future optical technologies will aid exploration of the Moon and Mars while advancing fundamental physics research in the solar system. Technologies and possible improvements in the laser-enabled tests of various physical phenomena are considered along with a space architecture that could be a cornerstone for robotic and human exploration in the solar system. In particular, accurate ranging to the Moon and Mars would not only lead to construction of a new space communication infrastructure enabling improved navigational accuracy, but would provide a significant improvement in several tests of gravitational theory: the equivalence principle, geodetic precession, PPN parameters beta and gamma, and the constancy of the gravitational constant G. Other tests would become possible with an optical architecture that would allow proceeding from cm to mm to sub-mm range accuracies. Looking to future exploration, what characteristics are desired for the next generation of ranging devices, what is the optimal architecture that would benefit both space exploration and fundamental physics, and what fundamental questions can be investigated?

Turyshev, Slava G.↗

STEREO Space Weather and the Space Weather Beacon

The Solar Terrestrial Relations Observatory (STEREO) is first and foremost a solar and interplanetary research mission, with one of the natural applications being in the area of space weather. The obvious potential for space weather applications is so great that NOAA has worked to incorporate the real-time data into their forecast center as much as possible. A subset of the STEREO data will be continuously downlinked in a real-time broadcast mode, called the Space Weather Beacon. Within the research community there has been considerable interest in conducting space weather related research with STEREO. Some of this research is geared towards making an immediate impact while other work is still very much in the research domain. There are many areas where STEREO might contribute and we cannot predict where all the successes will come. Here we discuss how STEREO will contribute to space weather and many of the specific research projects proposed to address STEREO space weather issues. We also discuss some specific uses of the STEREO data in the NOAA Space Environment Center.

Biesecker, D. A.↗

The NASA Solar System Exploration Virtual Institute: International Efforts in Advancing Lunar Science with Prospects for the Future

The NASA Solar System Exploration Research Virtual Institute (SSERVI), originally chartered in 2008 as the NASA Lunar Science Institute (NLSI), is chartered to advance both the scientific goals needed to enable human space exploration, as well as the science enabled by such exploration. NLSI and SSERVI have in succession been "institutes without walls," fostering collaboration between domestic teams (7 teams for NLSI, 9 for SSERVI) as well as between these teams and the institutes' international partners, resulting in a greater global endeavor. SSERVI teams and international partners participate in sharing ideas, information, and data arising from their respective research efforts, and contribute to the training of young scientists and bringing the scientific results and excitement of exploration to the public. The domestic teams also respond to NASA's strategic needs, providing community-based responses to NASA needs in partnership with NASA's Analysis Groups. Through the many partnerships enabled by NLSI and SSERVI, scientific results have well exceeded initial projections based on the original PI proposals, proving the validity of the virtual institute model. NLSI and SSERVI have endeavored to represent not just the selected and funded domestic teams, but rather the entire relevant scientific community; this has been done through many means such as the annual Lunar Science Forum (now re-named Exploration Science Forum), community-based grass roots Focus Groups on a wide range of topics, and groups chartered to further the careers of young scientists. Additionally, NLSI and SSERVI have co-founded international efforts such as the pan-European lunar science consortium, with an overall goal of raising the tide of lunar science (and now more broadly exploration science) across the world.

Institute↗

Revisiting the West Clearwater Lake Impact Structure, Canada

The West and East Clearwater Lake impact structures are two of the most distinctive and recognizable impact structures on Earth. Known regionally as the "Clearwater Lake Complex", these structures are located in northern Quebec, Canada (56 deg 10 N, 74 deg 20 W) approximately 125 km east of Hudson Bay. The currently accepted diameters are 36 km and 26 km for the West and East structures, respectively. Long thought to represent a rare example of a double impact, recent age dating has called this into question with ages of approximately 286 Ma and approximately 460-470 Ma being proposed for the West and East structures, respectively. Relatively little is known about the East Clearwater Lake structure. There is no surface exposure and what information there is comes from geophysics and two drill cores obtained in the 1960s. In contrast, the West Clearwater Lake structure is relatively well preserved with large ring of islands in the approximately 30 km diameter lake. Much of the work done on West Clearwater stems from field investigations carried out in 1977 driven by the Apollo program, with a focus on the impact melt rocks and other impactites, which are well exposed on the ring of islands. To our knowledge, the Clearwater Lake impact structures have not been the focus of detailed impact geology field investigations since the 1977 expedition and the only geological map that exists is from the 1960s and is at the reconnaissance level. Our knowledge of impact cratering processes have increased substantially since this time, as have the analytical techniques available for samples. This provided the motivation for a joint Canadian-US-UK expedition to the West Clearwater Lake impact structure in August and September 2015, under the auspices of the FINESSE (Field Investigations to Enable Solar System Science and Exploration) project, part of NASA's Solar System Exploration Research Virtual Institute (SSERVI). We focus here on the impactites of the West Clearwater Lake impact structure. Other ongoing studies, also presented at this conference, focus on central uplift formation, the impact-generated hydrothermal system, xxxx and using WCIS as an analog test site for crew studies of sampling protocols].

West Clearwater Lake↗

SSERVI: Merging Science and Human Exploration

The NASA Solar System Exploration Research Virtual Institute (SSERVI) is a virtual institute focused on research and the intersection of science and exploration, training the next generation of lunar scientists, and community development. As part of the SSERVI mission, we act as a hub for the opportunities that engage the larger scientific and exploration communities in order to form a new interdisciplinary, research-focused collaborations.

SSERVI↗

Reaction: Chemistry Driven by the Harsh Space Environment

The studies by Solar System Exploration Research Virtual Institute (SSERVI) teams such as REVEALS and DREAM2 not only connect back to the highest planetary science decadal goals regarding volatiles but also feed forward to understanding the chemical origins of potential resources at the surface useful for human exploration. See https://sservi.nasa.gov for more about SSERVI and its dynamic teams.

Farrell, William M.↗

NASA SSERVI: Merging Science and Human Exploration

The NASA Solar System Exploration Research Virtual Institute (SSERVI) is a virtual institute focused on research at the intersection of science and exploration, training the next generation of lunar scientists, and community development. As part of the SSERVI mission, we act as a hub for opportunities that engage the larger scientific and exploration communities in order to form new interdisciplinary, research-focused collaborations. This talk will describe the research efforts of the thirteen domestic teams that constitute the U.S. complement of the Institute and how we will engage the community through workshops, conferences, online seminars and classes, student exchange programs and internships.

SSERVI↗