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1. Practice Insights to Advance Racial Equity in Online Postsecondary Career and Technical Education: Lessons from the CTE CoLab. Research Report

Author

Urban Institute, World Education, Shayne Spaulding, Amanda Briggs, Izabela Solosi, Hailey D'Elia, Elise Colin, Theresa Anderson, Julia Payne, Sandy Goodman, Jan Vanek, and Darlene G. Miller

Abstract

The CTE CoLab, an Urban-led coalition of six national partners, guided 12 community and career and technical education (CTE) colleges through a two-and-a-half year, multistep equity action planning process focused on improving outcomes and advancing racial equity in online and hybrid CTE programs. College teams worked to understand gaps in outcomes for students of color and develop and implement strategies to address barriers to success stemming from historical, systemic, and institutional factors. This report documents the equity action planning process, strategies the colleges implemented to support students, and recommendations informed by lessons learned along the way. Strategies focused on increasing student supports, centering equity in online instruction delivery, and engaging with employers. Larger institutional changes sometimes required starting small, with a committed team bringing diverse expertise, roles, and experience to advance equity. Although the initiative's two-year timeframe proved challenging, colleges laid the groundwork to inform deeper and broader implementation of these strategies moving forward. [This report was produced with The National Council for Workforce Education.]

Published
2023

2. A Meta-Analysis of Mother-Child Synchrony in Respiratory Sinus Arrhythmia and Contextual Risk

Author

Jonas G. Miller, Emma Armstrong-Carter, Leah Balter, and Julie Lorah

Abstract

Biobehavioral frameworks of attachment posit that mother-child dyads engage in physiological synchrony that is uniquely formative for children's neurobiological, social, and emotional development. Much of the work on mother-child physiological synchrony has focused on respiratory sinus arrhythmia (RSA). However, the strength of the existing evidence for mother-child RSA synchrony during interaction is unclear. Using meta-analysis, we summarized results from 12 eligible studies comprising 14 samples and 1201 children ranging from infancy to adolescence (M[subscript age] = 5.68 years, SD = 4.13, range = 0.4-17 years) and their mothers. We found that there was a statistically significant, albeit modest, positive within-dyad association between mother and child fluctuations in RSA. There also was evidence for significant heterogeneity across studies. Less mother-child RSA synchrony was observed in high-risk samples characterized by clinical difficulties, history of maltreatment, or socioeconomic disadvantage. We did not find that mother-child RSA synchrony significantly differed by task context, mean child age, or by epoch length for computing RSA. Collectively, these findings suggest that mother-child dyads show correspondence in their fluctuations in RSA, and that RSA synchrony is disrupted in high-risk contexts. Future directions and implications for the study of parent-child physiological synchrony are discussed.

Published
2023
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3. Parent-Child Physiological Synchrony: Concurrent and Lagged Effects during Dyadic Laboratory Interaction

Author

Emma Armstrong-Carter, Jonas G. Miller, and Jelena Obradovic

Abstract

This study investigated whether parents and kindergarten children show concurrent and time-lagged physiological synchrony during dyadic interaction. Further, we tested whether parent-child behavioral co-regulation was associated with concurrent and time-lagged synchrony, and whether synchrony varied by the type of interaction task. Participants were 94 children (M[subscript age] = 5.6 years, 56% female) and their parents. We simultaneously measured parent and child respiratory sinus arrhythmia (RSA) during four dyadic interaction tasks: free play, clean up, problem-solving, and puzzle teaching. We found that synchrony varied by task. Concurrent synchrony occurred only during the puzzle teaching task, such that parent and child RSA were significantly and positively associated with each other simultaneously. Time-lagged synchrony occurred only during the problem-solving task, such that parent RSA was positively associated with child RSA 30 seconds later, and child RSA was negatively associated with parent RSA 30 seconds later. Although behavioral co-regulation and physiological synchrony have been conceptualized as markers of responsive parent-child interactions, our study finds no evidence that physiological synchrony is associated with between-dyad differences in behavioral co-regulation.

Published
2021
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4. Dynamic Crush Performance of Thermoplastic and Resin Infused Thermoset Triaxially Braided Composite Structures

Author

J. Michael Pereira, Brandon Strohminger, Niccolo Pini, Duane M. Revilock, Charles R. Ruggeri, and Sandi G. Miller

Subjects
Composite Materials
Abstract

Dynamic crush tests were conducted on triaxially braided composite tubes and C-channel structural elements to measure their relative energy absorbing characteristics. The elements were manufactured from triaxially braided [0/+60/-60] T700 fiber preforms with two different resin systems, a PR520 thermoset resin and a LM-PAEK thermoplastic resin. T700/PR520 composite tubes and C-channel elements were manufactured using a resin infusion process. T700GC/LMPAEK composite tubes were manufactured by braiding slit tape prepreg onto cylindrical mandrels. Consolidation pressure was applied through thermally activated shrink tape in an oven. The energy absorbing characteristics of the composite elements were measured using a pneumatically actuated sled with a flat-faced impacting mass, which provided several independent measurements of force, displacement, and energy absorption. The parameter primarily used for comparison between the systems was the specific energy absorption (SEA), a measure of energy absorbed per unit crushed length. The T700/LMPAEK tubes performed slightly better than T700/PR520 tubes, with an approximately 9% higher SEA. T700/PR520 tubes had over 20% higher SEA than C-channels made from the same material. Additional tests were conducted on tubes using a tapered-conical impactor to force the tubes to fail in circumferential tension. This type of impact significantly reduced the energy absorption.

Published
2023

5. Manufacturing and Mechanical Testing of TC1225/LM-PAEK and TC1200/PEEK Thermoplastic Composite Panels

Author

Sandi G. Miller, Paula J. Heimann, Ashley J. Miller, Daniel A. Scheiman, and Linda S. McCorkle

Subjects
Composite Materials
Abstract

Development of thermoplastic composites (TPCs) for aerospace structures is experiencing renewed enthusiasm attributed to the availability of rapid manufacturing technology, ease of joining through fusion welding processes, and the successful utilization of the material in flight critical structures. Semicrystalline thermoplastics such as polyether ether ketone (PEEK), polyether ketone ketone (PEKK), and polyphenylene sulfide (PPS) have been successfully demonstrated as thermoplastic skins, keel beams, and angle brackets for commercial aircraft. Composite specimens were fabricated from the Toray TC1225 and TC1200 unidirectional prepreg systems and tested to gain confidence with NASA in-house TPC processing as part of the Thermoplastics Development for Exploration Application (TDEA) project. TC1225 is a relatively new material system that uses T700GC fibers and low-melt polyaryl ether ketone (LM-PAEK) resin. TC1200 is the latest version of a material system that has been available for several decades with AS4 fibers and PEEK resin. Results for ultrasonic inspection, optical microscopy, acid digestion, and differential scanning calorimetry establish the quality of the panels. Mechanical test data for unnotched and notched laminate tension and compression as well as compression after impact provide data for equivalency assessment and support material selection in TDEA. Satisfactory equivalence of the TC1225 results and the National Center for Advanced Materials Performance (NCAMP) database was found. The results indicate high-quality manufacturing was achieved, and the resulting mechanical test data are in agreement with that in the literature.

Published
2023

6. Experimental Tests to Characterize the Behavior and Properties of IM7-8552 Composite

Author

Ashutosh Maurya, Seetha Pavan Tanneru, Subramaniam Rajan, J. Michael Pereira, and Sandi G. Miller

Subjects
Composite Materials
Abstract

This document summarizes the test procedures for characterizing the quasi-static (QS), room temperature (RT) behavior of IM7/8552 unidirectional composite material. All testing reported in this document follow applicable ASTM1 test standards as closely as possible, with any deviations reported. The overall objective is to develop a framework for the creation of MAT213 material input for use in the LS-DYNA program (LSTC, 2016). Details of the MAT213 material model and its implementation are available publicly (Goldberg et al., 2015; Harrington et al., 2016; Hoffarth et al., 2016). However, the measured properties can be utilized by most composite impact models.

Published
2023

7. Multiscale Progressive Failure Analysis of 3D Woven Composites

Author

Trenton M. Ricks, Evan J. Pineda, Brett A. Bednarcyk, Linda S. Mccorkle, Sandi G. Miller, Pappu L. N. Murthy, and Kenneth N. Segal

Subjects
Composite Materials
Abstract

Application of three-dimensional (3D) woven composites is growing as an alternative to the use of ply-based composite materials. However, the design, analysis, modeling, and optimization of these materials is more challenging due to their complex and inherently multiscale geometries. Herein, a multiscale modeling procedure, based on efficient, semi-analytical micromechanical theories rather than the traditional finite element approach, is presented and applied to a 3D woven carbon–epoxy composite. A crack-band progressive damage model was employed for the matrix constituent to capture the globally observed nonlinear response. Realistic microstructural dimensions and tow-fiber volume fractions were determined from detailed X-ray computed tomography (CT) and scanning electron microscopy data. Pre-existing binder-tow disbonds and weft-tow waviness, observed in X-ray CT scans of the composite, were also included in the model. The results were compared with experimental data for the in-plane tensile and shear behavior of the composite. The tensile predictions exhibited good correlations with the test data. While the model was able to capture the less brittle nature of the in-plane shear response, quantitative measures were underpredicted to some degree.

Published
2022
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8. A Comparison of Online and Face-to-Face Yoga in the Areas of Anxiety and Flexibility

Author

Robyn G. Miller

Abstract

This study employed a nonequivalent pretest-posttest comparison group design to measure whether online yoga is equal to or better than F2F yoga in terms of decreased anxiety, increased flexibility, and the perceptions of participants about how each course may have affected their behavioral intentions to practice yoga in the future. This study is a comparison between online yoga to face-to-face (F2F) yoga and how each delivery method affects anxiety and flexibility. It is important to understand whether online yoga can be an integral part in the health and wellness of individuals in the traditional college-age population. Analyses of covariance (ANCOVA) were employed to adjust for variability in pre-test scores. Based on results, the online format was significantly more effective in reducing the state anxiety of the students as compared to the F2F course. There was no significant difference between groups on trait anxiety. Furthermore, ANCOVA revealed that the F2F course was significantly more effective in reducing the appearance anxiety of students as compared to the online yoga course. With regard to degree of flexibility, the ANCOVA revealed that there was no significant difference between groups on flexibility of the students. The results suggest that online yoga has the potential to reduce certain types of anxiety and may be an effective component of health and wellness in the college-age population. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

Published
2019

9. Planet Hunters TESS II: findings from the first two years of TESS

Author

N L Eisner, O Barragán, C Lintott, S Aigrain, B Nicholson, T S Boyajian, S Howell, C Johnston, B Lakeland, G Miller, A McMaster, H Parviainen, E J Safron, M E Schwamb, L Trouille, S Vaughan, N Zicher, C Allen, S Allen, M Bouslog, C Johnson, M N Simon, Z Wolfenbarger, E M L Baeten, D M Bundy, and T Hoffman

Published
2020
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10. Planet Hunters TESS IV: A Massive, Compact Hierarchical Triple Star System TIC 470710327

Author

N. L. Eisner, C. Johnston, S. Toonen, A. J. Frost, S. Janssens, C J Lintott, S Aigrain, H Sana, M Abdul-Masih, K Z Arellano-Córdova, P G Beck, E Bordier, E Cannon, A Escorza, M Fabry, L Hermansson, S B Howell, G Miller, S Sheyte, S Alhassan, E M L Baeten, F Barnet, S J Bean, M Bernau, D M Bundy, M Z Di Fraia, F M Emralino, B L Goodwin, P Hermes, T Hoffman, M Huten, R Janíček, S Lee, M T Mazzucato, D J Rogers, M P Rout, J Sejpka, C Tanner, I A Terentev, and D Urvoy

Subjects
Astrophysics
Abstract

We report the discovery and analysis of a massive, compact, hierarchical triple system (TIC 470710327) initially identified by citizen scientists in data obtained by NASA’s Transiting Exoplanet Survey Satellite (TESS). Spectroscopic follow-up observations obtained with the HERMES spectrograph, combined with eclipse-timing variations (ETVs), confirm that the system is comprised of three OB stars, with a compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. Dynamical modelling of the system (from radial velocity and ETVs) reveal a rare configuration wherein the tertiary star (O9.5-B0.5V; 14–17 Mꙩ) is more massive than the combined mass of the inner binary (10.9–13.2 Mꙩ). Given the high mass of the tertiary, we predict that this system will undergo multiple phases of mass transfer in the future, and likely end up as a double neutron star gravitational wave progenitor or an exotic Thorne–Żytkow object. Further observational characterization of this system promises constraints on both formation scenarios of massive stars as well as their exotic evolutionary end-products.

Published
2022
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11. Novel Crash Sled with a Translating Support Mass

Author

R T Haluza, C R Ruggeri, J M Pereira, S G Miller, C E Bakis, and K L Koudela

Subjects
Composite Materials
Abstract

Background: A novel crash sled has been developed with a translating support, incorporating transducers that allow multiple methods of measuring energy absorption to fully characterize the dynamic crush response of composite components. Objective: The main goal of the current investigation was to demonstrate functionality, repeatability, and accuracy of crush testing using a crash sled with a translating support mass. Methods: A semi-automated algorithm for data reduction was developed based on impact mechanics principles. A preliminary set of tests was initially conducted using aluminum honeycomb specimens with a specified stable crushing force to quantify the accuracy and repeatability of the crush data. Following the success of these tests, triaxially-braided fiber-reinforced polymer (FRP) specimens were evaluated. Results: Crush tests with the aluminum honeycomb specimens showed excellent outcomes for all three specimens. These data provided close agreement with cumulative energy absorption between individual instruments and stable crushing forces at expected values. For the FRP specimens, specific energy absorption (SEA) and force-displacement curves were successfully measured; however, data from the translating support mass accelerometer was excluded from the dataset due to clipping. The SEA of the corrugated specimens was greater than the SEA for the C-channel specimens at both test speeds. Conclusions: The crash sled functionality was verified, the specimen geometry was found to contribute more to SEA than the impact speed in the speed range tested, and the support mass accelerometer will be upgraded to prevent clipping in future tests.

Published
2022
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12. SERENA: Particle Instrument Suite for Determining the Sun-Mercury Interaction from BepiColombo

Author

S. Orsini, S.A. Livi, H. Lichtenegger, S. Barabash, A. Milillo, E. De Angelis, M. Phillips, G. Laky, M. Wieser, A. Olivieri, C. Plainaki, G. Ho, R.M. Killen, J.A. Slavin, P. Wurz, J.-J. Berthelier, I. Dandouras, E. Kallio, S. McKenna-Lawlor, S. Szalai, K. Torkar, O. Vaisberg, F. Allegrini, I.A. Daglis, C. Dong, C.P. Escoubet, S. Fatemi, M. Fränz, S. Ivanovski, N. Krupp, H. Lammer, François Leblanc, V. Mangano, A. Mura, H. Nilsson, J.M. Raines, R. Rispoli, M. Sarantos, H.T. Smith, K. Szego, A. Aronica, F. Camozzi, A.M. Di Lellis, G. Fremuth, F. Giner, R. Gurnee, J. Hayes, H. Jeszenszky, F. Tominetti, B. Trantham, J. Balaz, W. Baumjohann, D. Brienza, U. Bührke, M.D. Bush, M. Cantatore, S. Cibella, L. Colasanti, G. Cremonese, L. Cremonesi, M. D’Alessandro, D. Delcourt, M. Delva, M. Desai, M. Fama, M. Ferris, H. Fischer, A. Gaggero, D. Gamborino, P. Garnier, W.C. Gibson, R. Goldstein, M. Grande, V. Grishin, D. Haggerty, M. Holmström, I. Horvath, K.-C. Hsieh, A. Jacques, R.E. Johnson, A. Kazakov, K. Kecskemety, H. Krüger, C. Kürbisch, F. Lazzarotto, Frederic Leblanc, M. Leichtfried, R. Leoni, A. Loose, D. Maschietti, S. Massetti, F. Mattioli, G. Miller, D. Moissenko, A. Morbidini, R. Noschese, F. Nuccilli, C. Nunez, N. Paschalidis, S. Persyn, D. Piazza, M. Oja, J. Ryno, W. Schmidt, J.A. Scheer, A. Shestakov, S. Shuvalov, K. Seki, S. Selci, K. Smith, R. Sordini, J. Svensson, L. Szalai, D. Toublanc, C. Urdiales, A. Varsani, N. Vertolli, R. Wallner, P. Wahlstroem, P. Wilson, and S. Zampieri

Subjects
Space Sciences (General)
Abstract

The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric particle dynamics at Mercury as well as their interactions with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for ion and neutral particle detection aboard the MPO. It comprises four independent sensors: ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA is managed by a System Control Unit located inside the ELENA box. In the present paper the scientific goals of this suite are described, and then the four units are detailed, as well as their major features and calibration results. Finally, the SERENA operational activities are shown during the orbital path around Mercury, with also some reference to the activities planned during the long cruise phase.

Published
2021
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13. Crash Sled Testing of Triaxially-Braided CFRP for Improved Vehicular Crashworthiness

Author

Charles R Ruggeri, Rudy T. Haluza, Mike Pereira, Sandi G Miller, Charles E. Bakis, and Kevin L. Koudela

Subjects
Composite Materials
Abstract

The Impact Dynamics Laboratory at NASA Glenn Research Center recently developed a pneumatically-actuated crash sled for investigating the crush behavior of structural elements for vehicular applications. The apparatus includes an adjustable striker mass and specimen support mass, which are mounted on separate rails. This setup provides two advantages over crash sleds with so-called fixed specimen supports: (i) it allows for multiple independent measurements of the crush response using different instruments, and (ii) the specimen support can be varied and its reaction can be explicitly measured. This paper describes the experimental setup and data analysis methodology and illustrates the capability of the sled for measuring the specific energy absorption (SEA) of triaxially-braided carbon/epoxy composite C-channels and corrugated plates. The corrugated plate had a higher SEA than the C-channel and the SEAs did not vary when the striker mass and velocity were changed so that incident energy was constant.

Published
2020

14. The unexpected surface of asteroid (101955) Bennu

Author

D. S. Lauretta, D. N. DellaGiustina, C. A. Bennett, D. R. Golish, K. J. Becker, S. S. Balram-Knutson, O. S. Barnouin, T. L. Becker, W. F. Bottke, W. V. Boynton, H. Campins, H. C. Connolly Jr, C. Y. Drouet d’Aubigny, J. P. Dworkin, J. P. Emery, H. L. Enos, V. E. Hamilton, C. W. Hergenrother, E. S. Howell, M. R. M. Izawa, H. H. Kaplan, M. C. Nolan, B. Rizk, H. L. Roper, D. J. Scheeres, P. H. Smith, K. J. Walsh, C. W. V. Wolner, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, L. McGraw, R. Ghent, R. P. Binzel, M. M. Al Asad, C. L. Johnson, L. Philpott, H. C. M. Susorney, E. A. Cloutis, R. D. Hanna, F. Ciceri, A. R. Hildebrand, E.-M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J. R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M. K. Crombie, C. Lantz, J. de Leon, J. Licandro, J. L. Rizos Garcia, S. Clemett, K. Thomas-Keprta, S. Van wal, M. Yoshikawa, J. Bellerose, S. Bhaskaran, C. Boyles, S. R. Chesley, C. M. Elder, D. Farnocchia, A. Harbison, B. Kennedy, A. Knight, N. Martinez-Vlasoff, N. Mastrodemos, T. McElrath, W. Owen, R. Park, B. Rush, L. Swanson, Y. Takahashi, D. Velez, K. Yetter, C. Thayer, C. Adam, P. Antreasian, J. Bauman, C. Bryan, B. Carcich, M. Corvin, J. Geeraert, J. Hoffman, J. M. Leonard, E. Lessac-Chenen, A. Levine, J. McAdams, L. McCarthy, D. Nelson, B. Page, J. Pelgrift, E. Sahr, K. Stakkestad, D. Stanbridge, D. Wibben, B. Williams, K. Williams, P. Wolff, P. Hayne, D. Kubitschek, M. A. Barucci, J. D. P. Deshapriya, S. Fornasier, M. Fulchignoni, P. Hasselmann, F. Merlin, A. Praet, E. B. Bierhaus, O. Billett, A. Boggs, B. Buck, S. Carlson-Kelly, J.Cerna, K. Chaffin, E. Church, M. Coltrin, J. Daly, A. Deguzman, R. Dubisher, D. Eckart, D. Ellis, P. Falkenstern, A. Fisher, M. E. Fisher, P. Fleming, K. Fortney, S. Francis, S. Freund, S. Gonzales, P. Haas, A. Hasten, D. Hauf, A. Hilbert, D. Howell, F. Jaen, N. Jayakody, M. Jenkins, K. Johnson, M. Lefevre, H. Ma, C. Mario, K. Martin, C. May, M. McGee, B. Miller, C. Miller, G. Miller, A. Mirfakhrai, E. Muhle, C. Norman, R. Olds, C. Parish, M. Ryle, M. Schmitzer, P. Sherman, M. Skeen, M. Susak, B. Sutter, Q. Tran, C. Welch, R. Witherspoon, J. Wood, J. Zareski, M. Arvizu-Jakubicki, E. Asphaug, E. Audi, R.-L. Ballouz, R. Bandrowski, S. Bendall, H. Bloomenthal, D. Blum, J. Brodbeck, K. N. Burke, M. Chojnacki, A. Colpo, J. Contreras, J. Cutts, D. Dean, B. Diallo, D. Drinnon, K. Drozd, R. Enos, C. Fellows, T. Ferro, M. R. Fisher, G. Fitzgibbon, M. Fitzgibbon, J. Forelli, T. Forrester, I. Galinsky, R. Garcia, A. Gardner, N. Habib, D. Hamara, D. Hammond, K. Hanley, K. Harshman, K. Herzog, D. Hill, C. Hoekenga, S. Hooven, E. Huettner, A. Janakus, J. Jones, T. R. Kareta, J. Kidd, K. Kingsbury, L. Koelbel, J. Kreiner, D. Lambert, C. Lewin, B. Lovelace, M. Loveridge, M. Lujan, C. K. Maleszewski, R. Malhotra, K. Marchese, E. McDonough, N. Mogk, V. Morrison, E. Morton, R. Munoz, J. Nelson, J. Padilla, R. Pennington, A. Polit, N. Ramos, V. Reddy, M. Riehl, S. Salazar, S. R. Schwartz, S. Selznick, N. Shultz, S. Stewart, S. Sutton, T. Swindle, Y. H. Tang, M. Westermann, D. Worden, T. Zega, Z. Zeszut, A. Bjurstrom, L. Bloomquist, C. Dickinson, E. Keates, J. Liang, V. Nifo, A. Taylor, F. Teti, M. Caplinger, H. Bowles, S. Carter, S. Dickenshied, D. Doerres, T. Fisher, W. Hagee, J. Hill, M. Miner, D. Noss, N. Piacentine, M. Smith, A. Toland, P. Wren, M. Bernacki, D. Pino Munoz, S.-i. Watanabe, S. A. Sandford, A. Aqueche, B. Ashman, M. Barker, A. Bartels, K. Berry, B. Bos, R. Burns, A. Calloway, R. Carpenter, N. Castro, R. Cosentino, J. Donaldson, J. Elsila Cook, C. Emr, D. Everett, D. Fennell, K. Fleshman, D. Folta, D. Gallagher, J. Garvin, K. Getzandanner, D. Glavin, S. Hull, K. Hyde, H. Ido, A. Ingegneri, N. Jones, P. Kaotira, L. F. Lim, A. Liounis, C. Lorentson, D. Lorenz, J. Lyzhoft, E. M. Mazarico, R. Mink, W. Moore, M. Moreau, S. Mullen, J. Nagy, G. Neumann, J. Nuth, D. Poland, D. C. Reuter, L. Rhoads, S. Rieger, D. Rowlands, D. Sallitt, A. Scroggins, G. Shaw, A. A. Simon, J. Swenson, P. Vasudeva, M. Wasser, R. Zellar, J. Grossman, G. Johnston, M. Morris, J. Wendel, A. Burton, L. P. Keller, L. Mcnamara, S. Messenger, K. Messenger, A. Nguyen, K. Righter, E. Queen, K. Bellamy, K. Dill, S. Gardner, M. Giuntini, B. Key, J. Kissell, D. Patterson, D. Vaughan, B. Wright, R. W. Gaskell, L. Le Corre, J.-Y. Li, J. L. Molaro, E. E. Palmer, M. A. Siegler, P. Tricarico, J. R. Weirich, X.-D. Zou, T. Ireland, K. Tait, P. Bland, S. Anwar, N. Bojorquez-Murphy, P. R. Christensen, C. W. Haberle, G. Mehall, K. Rios, I. Franchi, B. Rozitis, C. B. Beddingfield, J. Marshall, D. N. Brack, A. S. French, J. W. McMahon, E. R. Jawin, T. J. McCoy, S. Russell, M. Killgore, J. L. Bandfield, B. C. Clark, M. Chodas, M. Lambert, R. A. Masterson, M. G. Daly, J. Freemantle, J. A. Seabrook, K. Craft, R. T. Daly, C. Ernst, R. C. Espiritu, M. Holdridge, M. Jones, A. H. Nair, L. Nguyen, J. Peachey, M. E. Perry, J. Plescia, J. H. Roberts, R. Steele, R. Turner, J. Backer, K. Edmundson, J. Mapel, M. Milazzo, S. Sides, C. Manzoni, B. May, M. Delbo, G. Libourel, P. Michel, A. Ryan, F. Thuillet, and B. Marty

Subjects
Astronomy, Exobiology
Abstract

NASA’S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth1. Bennu is a low-albedo B-type asteroid2 that has been linked to organic-rich hydrated carbonaceous chondrites3. Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine—that is, not affected by these processes4. The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu’s global properties, support the selection of a sampling site and document that site at a sub-centimetre scale5,6,7,8,9,10,11. Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid’s properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu’s thermal inertia12 and radar polarization ratios13—which indicated a generally smooth surface covered by centimetre-scale particles—resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-metre-diameter patches of loose regolith with grain sizes smaller than two centimetres4. We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 metres in extent, the sampling of which poses a substantial challenge to mission success.

Published
2019
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15. The operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations

Author

C. W. Hergenrother, C. K. Maleszewski, M. C. Nolan, J.-Y. Li, C. Y. Drouet d’Aubigny, F. C. Shelly, E. S. Howell, T. R. Kareta, M. R. M. Izawa, M. A. Barucci, E. B. Bierhaus, S. R. Chesley, B. E. Clark, E. J. Christensen, D. N. DellaGiustina, S. Fornasier, D. R. Golish, C. M. Hartzell, B. Rizk, D. J. Scheeres, P. H. Smith, X.-D. Zou, D. S. Lauretta, Jason Peter Dworkin, D.E. Highsmith, J. Small, D. Vokrouhlický, N.E. Bowles, E. Brown, K.L. Donaldson Hanna, T. Warren, C. Brunet, R.A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D.L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C.M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J.P. Emery, L. McGraw, R. Ghent, R.P. Binzel, M.M. Al Asad, C.L. Johnson, L. Philpott, H.C.M. Susorney, E.A. Cloutis, R.D. Hanna, H.C. Connolly Jr, F. Ciceri, A.R. Hildebrand, E.-M. Ibrahim, L. Breitenfeld, T. Glotch, A.D. Rogers, B.E. Clark, S. Ferrone, C.A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J.R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M.K. Crombie, C. Lantz, M.R.M. Izawa, J. de Leon, J. Licandro, J.L.Rizos Garcia, S. Clemett, K. Thomas-Keprta, S. Van wal, M. Yoshikawa, J. Bellerose, S. Bhaskaran, C. Boyles, S.R. Chesley, C.M. Elder, D. Farnocchia, A. Harbison, B. Kennedy, A. Knight, N. Martinez-Vlasoff, N. Mastrodemos, T. McElrath, W. Owen, R. Park, B. Rush, L. Swanson, Y. Takahashi, D. Velez, K. Yetter, C. Thayer, C. Adam, P. Antreasian, J. Bauman, C. Bryan, B. Carcich, M. Corvin, J. Geeraert, J. Hoffman, J.M. Leonard, E. Lessac-Chenen, A. Levine, J. McAdams, L. McCarthy, D. Nelson, B. Page, J. Pelgrift, E. Sahr, K. Stakkestad, D. Stanbridge, D. Wibben, B. Williams, K. Williams, P. Wolff, P. Hayne, D. Kubitschek, M.A. Barucci, J.D.P. Deshapriya, M. Fulchignoni, P. Hasselmann, F. Merlin, A. Praet, E.B. Bierhaus, O. Billett, A. Boggs, B. Buck, S. Carlson-Kelly, J. Cerna, K. Chaffin, E. Church, M. Coltrin, J. Daly, A. Deguzman, R. Dubisher, D. Eckart, D. Ellis, P. Falkenstern, A. Fisher, M.E. Fisher, P. Fleming, K. Fortney, S. Francis, S. Freund, S. Gonzales, P. Haas, A. Hasten, D. Hauf, A. Hilbert, D. Howell, F. Jaen, N. Jayakody, M. Jenkins, K. Johnson, M. Lefevre, H. Ma, C. Mario, K. Martin, C. May, M. McGee, B. Miller, C. Miller, G. Miller, A. Mirfakhrai, E. Muhle, C. Norman, R. Olds, C. Parish, M. Ryle, M. Schmitzer, P. Sherman, M. Skeen, M. Susak, B. Sutter, Q. Tran, C. Welch, R. Witherspoon, J. Wood, J. Zareski, M. Arvizu-Jakubicki, E. Asphaug, E. Audi, R.-L. Ballouz, R. Bandrowski, K.J. Becker, T.L. Becker, S. Bendall, C.A. Bennett, H. Bloomenthal, D. Blum, W.V. Boynton, J. Brodbeck, K.N. Burke, M. Chojnacki, A. Colpo, J. Contreras, J. Cutts, C. Y. Drouet d'Aubigny, D. Dean, D.N. DellaGiustina, B. Diallo, D. Drinnon, K. Drozd, H.L. Enos, R. Enos, C. Fellows, T. Ferro, M.R. Fisher, G. Fitzgibbon, M. Fitzgibbon, J. Forelli, T. Forrester, I. Galinsky, R. Garcia, A. Gardner, D.R. Golish, N. Habib, D. Hamara, D. Hammond, K. Hanley, K. Harshman, C.W. Hergenrother, K. Herzog, D. Hill, C. Hoekenga, S. Hooven, E.S. Howell, E. Huettner, A. Janakus, J. Jones, T.R. Kareta, J. Kidd, K. Kingsbury, S.S. Balram-Knutson, L. Koelbel, J. Kreiner, D. Lambert, D.S. Lauretta, C. Lewin, B. Lovelace, M. Loveridge, M. Lujan, C.K. Maleszewski, R. Malhotra, K. Marchese, E. McDonough, N. Mogk, V. Morrison, E. Morton, R. Munoz, J. Nelson, M.C. Nolan, J. Padilla, R. Pennington, A. Polit, N. Ramos, V. Reddy, M. Riehl, Y.H. Tang, M. Westermann, C.W.V. Wolner, D. Worden, T. Zega, Z. Zeszut, A. Bjurstrom, L. Bloomquist, C. Dickinson, E. Keates, J. Liang, V. Nifo, A. Taylor, F. Teti, M. Caplinger, H. Bowles, S. Carter, S. Dickenshied, D. Doerres, T. Fisher, W. Hagee, J. Hill, M. Miner, D. Noss, N. Piacentine, M. Smith, A. Toland, P. Wren, M. Bernacki, D. Pino Munoz, S.-i. Watanabe, S. A. Sandford, A. Aqueche, B. Ashman, M. Barker, A. Bartels, K. Berry, B. Bos, R. Burns, A. Calloway, R. Carpenter, N. Castro, R. Cosentino, J. Donaldson, J.P. Dworkin, J. Elsila Cook, C. Emr, D. Everett, D. Fennell, K. Fleshman, D. Folta, D. Gallagher, J. Garvin, K. Getzandanner, D. Glavin, S. Hull, K. Hyde, H. Ido, A. Ingegneri, N. Jones, P. Kaotira, L.F. Lim, A. Liounis, C. Lorentson, D. Lorenz, J. Lyzhoft, E.M. Mazarico, R. Mink, W. Moore, M. Moreau, S. Mullen, J. Nagy, G. Neumann, J. Nuth, D. Poland, D.C. Reuter, L. Rhoads, S. Rieger, D. Rowlands, D. Sallitt, A. Scroggins, G. Shaw, A.A. Simon, J. Swenson, P. Vasudeva, M. Wasser, R. Zellar, J. Grossman, G. Johnston, M. Morris, J. Wendel, A. Burton, L.P. Keller, L. McNamara, S. Messenger, K. Nakamura-Messenger, A. Nguyen, K. Righter, E. Queen, K. Bellamy, K. Dill, S. Gardner, M. Giuntini, B. Key, J. Kissell, D. Patterson, D. Vaughan, B. Wright, R.W. Gaskell, L. Le Corre, J.L. Molaro, E.E. Palmer, M.A. Siegler, P. Tricarico, J.R. Weirich, T. Ireland, K. Tait, P. Bland, S. Anwar, A.S. French, J.W. McMahon, D.J. Scheeres, E.R. Jawin, T.J. McCoy, S. Russell, M. Killgore, W.F. Bottke, V.E. Hamilton, H.H. Kaplan, K.J. Walsh, J.L. Bandfield, B.C. Clark, M. Chodas, M. Lambert, R.A. Masterson, M.G. Daly, J. Freemantle, J.A. Seabrook, O.S. Barnouin, K. Craft, R.T. Daly, C. Ernst, R.C. Espiritu, M. Holdridge, M. Jones, A.H. Nair, L. Nguyen, J. Peachey, M.E. Perry, J. Plescia, J.H. Roberts, R. Steele, R. Turner, J. Backer, K. Edmundson, J. Mapel, M. Milazzo, S. Sides, C. Manzoni, B. May, M. Delbo’, G. Libourel, P. Michel, A. Ryan, F. Thuillet, and B. Marty

Subjects
Geosciences (General)
Abstract

During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission’s safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu’s surface to an upper limit of 150 g/s averaged over 34 min. Bennu’s disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu’s rotation rate is accelerating continuously at 3.63 ± 0.52 × 10^(–6) degrees/sq. day, likely due to the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, with evolutionary implications.

Published
2019
Full Text
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17. GEM: Statistical weather forecasting procedure

Author

Robert G. Miller

Subjects
Meteorology And Climatology
Abstract

The objective of the Generalized Exponential Markov (GEM) Program was to develop a weather forecast guidance system that would: predict between 0 to 6 hours all elements in the airways observations; respond instantly to the latest observed conditions of the surface weather; process these observations at local sites on minicomputing equipment; exceed the accuracy of current persistence predictions at the shortest prediction of one hour and beyond; exceed the accuracy of current forecast model output statistics inside eight hours; and be capable of making predictions at one location for all locations where weather information is available.

Published
1982

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