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34 results on '"Prem, Parvathy"'

1. 18 Surface Volatiles on the Moon

Author

Hurley, Dana M., primary, Siegler, Matthew A., additional, Cahill, Joshua T. S., additional, Colaprete, Anthony, additional, Costello, Emily, additional, Deutsch, Ariel N., additional, Elphic, Richard C., additional, Fa, Wenzhe, additional, Grava, Cesare, additional, Hayne, Paul O., additional, Heldmann, Jennifer, additional, Hendrix, Amanda R., additional, Jordan, Andrew P., additional, Killen, Rosemary M., additional, Klima, Rachel L., additional, Kramer, Georgiana, additional, Li, Shuai, additional, Liu, Yang, additional, Lucey, Paul G., additional, Mazarico, Erwan, additional, Pendleton, Yvonne, additional, Poston, Michael, additional, Prem, Parvathy, additional, Retherford, Kurt D., additional, and Schaible, Micah, additional

Published
2024
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3. Managing Activities at the Lunar Poles for Science

Author

Crawford, Ian A., Prem, Parvathy, Peters, Carle, and Anand, Mahesh

Subjects
Physics - Physics and Society, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The lunar poles are unique environments of both great scientific and, increasingly, commercial interest. Consequently, a tension exists between the twin objectives of (a) Exploring the lunar poles for both scientific and commercial purposes and ultimately supporting a lunar economy; and (b) Minimising the environmental impacts on the lunar polar regions so as to preserve them for future scientific investigations. We suggest that the best compromise between these equally valuable objectives would be to restrict scientific and commercial activities to the lunar South Pole, while placing a moratorium on activities at the North Pole until the full consequences of human activities at the South Pole are fully understood and mitigation protocols established. Depending on the pace at which lunar exploration proceeds, such a moratorium might last for several decades in order to properly assess the effects of exploration and commercial activities in regions surrounding the South Pole. A longer term possibility might be to consider designating the lunar North Polar region as a (possibly temporary) Planetary Park. Similar protected status might also be desirable for other unique lunar environments, and, by extension, other scientifically important localities elsewhere in the Solar System., Comment: Accepted for publication in Space Research Today; 7 pages, 1 figure

Published
2022

4. Exosphere-Mediated Migration of Volatile Species On Airless Bodies Across the Solar System

Author

Steckloff, Jordan K., Goldstein, David, Trafton, Laurence, Varghese, Philip, and Prem, Parvathy

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Surface-bound exospheres facilitate volatile migration across the surfaces of nearly airless bodies. However, such transport requires that the body can both form and retain an exosphere. To form a sublimation exosphere requires the surface of a body to be sufficiently warm for surface volatiles to sublime; to retain an exosphere, the ballistic escape and photodestruction rates and other loss mechanisms must be sufficiently low. Here we construct a simple free molecular model of exospheres formed by volatile desorption/sublimation. We consider the conditions for forming and retaining exospheres for common volatile species across the Solar System, and explore how three processes (desorption/sublimation, ballistic loss, and photodestruction) shape exospheric dynamics on airless bodies. Our model finds that the CO2 exosphere of Callisto is too dense to be sustained by impact-delivered volatiles, but could be maintained by only ~7 hectares of exposed CO2 ice. We predict the peak surface locations of Callisto's CO2 exosphere along with other Galilean moons, which could be tested by JUICE observations. Our model finds that to maintain Iapetus' two-tone appearance, its dark Cassini Regio likely has unresolved exposures of water ice, perhaps in sub-resolution impact craters, that amount to up to ~0.06% of its surface. In the Uranian system, we find that the CO2 deposits on Ariel, Umbriel, Titania, and Oberon are unlikely to have been delivered via impacts, but are consistent with both a magnetospheric origin or sourced endogenously. We suggest that exosphere-mediated volatile transport could produce these moons' leading/trailing CO2 asymmetries, and may be a seasonal equinox feature that could be largely erased by volatile migration during the Uranian solstices. We calculate that ~2.4-6.4 mm thick layer of CO2 could migrate about the surface of Uranus' large moons during a seasonal cycle.

Published
2022
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6. Understanding and Mitigating Plume Effects During Powered Descents on the Moon and Mars

Author

Watkins, Ryan N., Metzger, Philip T., Mehta, Manish, Han, Daoru, Prem, Parvathy, Sibille, Laurent, Dove, Adrienne, Jolliff, Bradley, Moriarty III, Daniel P., Barker, Donald C., Patrick, Ed, Kuhns, Matthew, and Laine, Michael

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Physics - Space Physics
Abstract

This 2020 Decadal Survey White Paper reviews what is known about lunar and martian lander Plume Surface Interactions (PSI) during powered descent. This includes an overview of the phenomenology and a description of the induced hardware and environmental impacts. Then it provides an overview of mitigation techniques and a summary of the outstanding questions and strategic knowledge gaps. It finishes with five recommendations: to include dedicated descent imagers on every surface mission so that PSI can be directly recorded and reviewed by ground teams; as far as possible, to make all data related to PSI effects publicly accessible; to develop methods and instruments for making key measurements of PSI; to assess and record key flight data; and to invest funding into studies of long-term infrastructure architectures and mitigation techniques., Comment: 8 pages

Published
2021

7. Lunar Volatiles and Solar System Science

Author

Prem, Parvathy, Kereszturi, Ákos, Deutsch, Ariel N., Hibbitts, Charles A., Schmidt, Carl A., Grava, Cesare, Honniball, Casey I., Hardgrove, Craig J., Pieters, Carlé M., Goldstein, David B., Barker, Donald C., Needham, Debra H., Hurley, Dana M., Mazarico, Erwan, Dominguez, Gerardo, Patterson, G. Wesley, Kramer, Georgiana Y., Brisset, Julie, Gillis-Davis, Jeffrey J., Mitchell, Julie L., Szalay, Jamey R., Halekas, Jasper S., Keane, James T., Head, James W., Mandt, Kathleen E., Robinson, Katharine L., Luchsinger, Kristen M., Magaña, Lizeth O., Siegler, Matthew A., Landis, Margaret E., Poston, Michael J., Petro, Noah E., Lucey, Paul G., Killen, Rosemary M., Li, Shuai, Narendranath, Shyama, Shukla, Shashwat, Barrett, Thomas J., Stubbs, Timothy J., Orlando, Thomas M., and Farrell, William M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Understanding the origin and evolution of the lunar volatile system is not only compelling lunar science, but also fundamental Solar System science. This white paper (submitted to the US National Academies' Decadal Survey in Planetary Science and Astrobiology 2023-2032) summarizes recent advances in our understanding of lunar volatiles, identifies outstanding questions for the next decade, and discusses key steps required to address these questions.

Published
2020

9. Ethical Exploration and the Role of Planetary Protection in Disrupting Colonial Practices

Author

Tavares, Frank, Buckner, Denise, Burton, Dana, McKaig, Jordan, Prem, Parvathy, Ravanis, Eleni, Trevino, Natalie, Venkatesan, Aparna, Vance, Steven D., Vidaurri, Monica, Walkowicz, Lucianne, and Wilhelm, Mary Beth

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We recommend that the planetary science and space exploration community engage in a robust reevaluation concerning the ethics of how future crewed and uncrewed missions to the Moon and Mars will interact with those planetary environments. This should occur through a process of community input, with emphasis on how such missions can resist colonial structures. Such discussions must be rooted in the historical context of the violent colonialism in the Americas and across the globe that has accompanied exploration of Earth. The structures created by settler colonialism are very much alive today, impact the scientific community, and are currently replicated in the space exploration communities' plans for human exploration and in-situ resource utilization. These discussions must lead to enforceable planetary protection policies that create a framework for ethical exploration of other worlds. Current policy does not adequately address questions related to in-situ resource utilization and environmental preservation and is without enforcement mechanisms. Further, interactions with potential extraterrestrial life have scientific and moral stakes. Decisions on these topics will be made in the coming decade as the Artemis program enables frequent missions to the Moon and crewed missions to Mars. Those first choices will have irreversible consequences for the future of human space exploration and must be extremely well considered, with input from those beyond the scientific community, including expertise from the humanities and members of the general public. Without planetary protection policy that actively resists colonial practices, they will be replicated in our interactions and exploration of other planetary bodies. The time is now to engage in these difficult conversations and disrupt colonial practices within our field so that they are not carried to other worlds., Comment: A submission to the Planetary Science and Astrobiology Decadal Survey 2023-2032

Published
2020

10. Volatile interactions with the lunar surface

Author

Lucey, Paul G., Petro, Noah, Hurley, Dana M., Farrell, William M., Prem, Parvathy, Costello, Emily S., Cable, Morgan L., Barker, Michael K., Benna, Mehdi, Dyar, M. Darby, Fisher, Elizabeth A., Green, Robert O., Hayne, Paul O., Hibbitts, Karl, Honniball, Casey, Li, Shuai, Malaret, Erick, Mandt, Kathy, Mazarico, Erwan, McCanta, Molly, Pieters, Carle, Sun, Xiaoli, Thompson, David, and Orlando, Thomas

Published
2022
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11. Surface Exospheric Interactions

Author

Teolis, Ben, Sarantos, Menelaos, Schorghofer, Norbert, Jones, Brant, Grava, Cesare, Mura, Alessandro, Prem, Parvathy, Greenhagen, Ben, Capria, Maria Teresa, Cremonese, Gabriele, Lucchetti, Alice, and Galluzzi, Valentina

Published
2023
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12. Surface Roughness at the Moon’s South Pole: The Influence of Condensed Volatiles on Surface Roughness at the Moon’s South Pole

Author

Magaña, Lizeth O., primary, Prem, Parvathy, additional, Deutsch, Ariel N., additional, Martin, Anna C., additional, Meyer, Heather M., additional, Fassett, Caleb I., additional, Barker, Michael K., additional, Stickle, Angela, additional, Byron, Benjamin D., additional, Mandt, Kathleen E., additional, and Retherford, Kurt D., additional

Published
2024
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14. The Value of the Moon for Heliophysics

Author

Halekas, Jasper, primary, Sarantos, Menelaos, additional, Regoli, Leonardo, additional, Harada, Yuki, additional, Zheng, Yihua, additional, Nishino, Masaki, additional, Vines, Sarah, additional, Szalay, Jamey, additional, Chi, Peter, additional, Leon, Omar, additional, Denevi, Brett, additional, Sibeck, David, additional, Chen, Li-Jen, additional, Hartzell, Christine, additional, Horanyi, Mihaly, additional, Stanier, Adam, additional, Lillis, Rob, additional, Haviland, Heidi Fuqua, additional, Wang, Xu, additional, Keller, John, additional, Zou, Xiao-Duan, additional, Chu, Feng, additional, Cao, Xin, additional, Xu, Shaosui, additional, Liuzzo, Lucas, additional, Kurth, William, additional, Hospodarsky, George, additional, Angelopoulos, Vassilis, additional, Yokota, Shoichiro, additional, Fatemi, Shahab, additional, Miyoshi, Yoshizumi, additional, Morrissey, Liam, additional, Bale, Stuart, additional, Sawyer, Rhyan, additional, Jordan, Andrew, additional, Alves, Mauro, additional, Prem, Parvathy, additional, Allen, Robert, additional, Ridenti, Marco, additional, Waller, Dany, additional, Blewett, David, additional, Malaspina, David, additional, Tucker, Orenthal, additional, Poppe, Andrew, additional, Nord, Michael, additional, Grava, Cesare, additional, Hood, Lon, additional, Deca, Jan, additional, Wit, Thierry Dudok de, additional, Ho, George, additional, Kramer, Georgiana, additional, Krasnoselskikh, Vladimir, additional, and Saxena, Prabal, additional

Published
2023
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18. Inclusive Lunar Exploration

Author

Bennett, Kristen, Prem, Parvathy, Ahrens, Caitlin, Kumari, Nandita, Pigue, Lori, Sehlke, Alex, and Tai Udovicic, Christian J.

Abstract

This report summarizes findings from the Inclusive Lunar Exploration workshop (Virtual Session 13 in the Lunar Surface Science Workshop series), held January 26-27, 2022.

Published
2022
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20. Temperatures of the Lacus Mortis Region of the Moon

Author

Williams, Jean‐Pierre, primary, Greenhagen, Benjamin T., additional, Bennett, Kristen A., additional, Paige, David A., additional, Kumari, Nandita, additional, Ahrens, Caitlin J., additional, Rubanenko, Lior, additional, Powell, Tyler M., additional, Prem, Parvathy, additional, Blewett, David T., additional, Russell, Patrick S., additional, Hayne, Paul O., additional, and Sullivan, Mark T., additional

Published
2022
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22. Mission to Characterize Volatiles in Old, Cold, Permanently Shadowed Regions on the Moon

Author

Hurley, Dana, primary, Blewett, David T., additional, Cahill, Joshua, additional, Chabot, Nancy, additional, Greenhagen, Benjamin, additional, Hibbitts, Charles, additional, Klima, Rachel, additional, Lawrence, David, additional, Mandt, Kathleen, additional, Nunez, Jorge I., additional, Patterson, Wes, additional, Prem, Parvathy, additional, Stickle, Angela, additional, Deutsch, Ariel, additional, Delitsky, Mona, additional, Flahaut, Jessica, additional, Sowers, George, additional, Sefton-Nash, Eliot, additional, Brisset, Julie, additional, Zacny, Kris, additional, Shukla, Shashwat, additional, Grandidier, Jonathan, additional, Hosseini, Sona, additional, Liu, Yang, additional, Bhiravarasu, Sriram, additional, Stopar, Julie, additional, Barker, Donald, additional, Gertsch, Leslie, additional, Jha, Devanshu, additional, Colaprete, Anthony, additional, Elphic, Richard, additional, Banks, Maria, additional, Benna, Mehdi, additional, Farrell, William, additional, Saxena, Prabal, additional, Tucker, O.J., additional, Mitchell, Julie, additional, Needham, Debra, additional, Atkinson, Jared, additional, Barber, Simeon, additional, Hendrix, Amanda, additional, Kramer, Georgiana, additional, Siegler, Matthew, additional, Grava, Cesare, additional, Poston, Michael, additional, Retherford, Kurt, additional, Kumari, Nandita, additional, Barnes, Jessica, additional, Hayne, Paul, additional, Li, Shuai, additional, Lucey, Paul, additional, and Livengood, Timothy, additional

Published
2021
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26. Lunar Volatiles Orbiters

Author

Lucey, Paul G., primary, Prem, Parvathy, additional, Cable, Morgan L., additional, Hibbitts, Charles A., additional, Honniball, Casey I., additional, Pieters, Carlé M., additional, Barker, Michael, additional, Benna, Mehdi, additional, Dyar, Darby, additional, Fisher, Elizabeth, additional, Hayne, Paul, additional, Li, Shuai, additional, McCanta, Molly, additional, Hurley, Dana M., additional, Mazarico, Erwan, additional, Mandt, Kathleen E., additional, Petro, Noah E., additional, Orlando, Thomas M., additional, and Farrell, William M., additional

Published
2021
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27. Lunar polar volatile resources: Obtaining their origin prior to extraction

Author

Farrell, William, primary, Beltran, Esther, additional, Prem, Parvathy, additional, Poston, Michael, additional, Deutsch, Ariel, additional, Hurley, Dana, additional, Retherford, Kurt, additional, Hayne, Paul, additional, Horanyi, Mihaly, additional, Orlando, Thomas, additional, Gillis-Davis, Jeffrey, additional, Dominguez, Gerardo, additional, Shukla, Shashwat, additional, Szalay, Jamey, additional, Needham, Debra, additional, Landis, Margaret, additional, Mandt, Kathleen, additional, Bennett, Christopher, additional, and Grava, Cesare, additional

Published
2021
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28. Science Opportunities offered by Mercury’s Ice-Bearing Polar Deposits

Author

Deutsch, Ariel, primary, Chabot, Nancy, additional, Maiti, Abhisek, additional, Luspay-Kuti, Adrienn, additional, Kereszturi, Akos, additional, Lucchetti, Alice, additional, Virkki, Anne, additional, Colaprete, Anthony, additional, Vorburger, Audrey, additional, Byron, Ben, additional, Jones, Brant, additional, Anzures, Brendan, additional, Butler, Bryan, additional, Schmidt, Carl, additional, Ernst, Carolyn, additional, Grava, Cesare, additional, Klimczak, Christian, additional, Dong, Chuanfei, additional, Hamill, Colin, additional, Hardgrove, Craig, additional, Blewett, David, additional, Lawrence, David, additional, Hickson, Dylan, additional, Rivera-Valentin, Edgard, additional, Costello, Emily, additional, Mazarico, Erwan, additional, Filacchione, Gianrico, additional, Bacon, Giovanni, additional, Neumann, Gregory, additional, Susorney, Hannah, additional, Brown, Holly, additional, Varatharajan, Indhu, additional, Wilson, Jack, additional, Kloos, Jacob, additional, Head, James, additional, Szalay, Jamey, additional, Steckloff, Jordan, additional, Miller, Kelly, additional, Cannon, Kevin, additional, Luchsinger, Kristen, additional, Rubanenko, Lior, additional, Magana, Lizeth, additional, Landis, Margaret, additional, Gritsevich, Maria, additional, Schneegurt, Mark, additional, Slade, Martin, additional, Siegler, Matthew, additional, Pajola, Maurizio, additional, Sarantos, Menelaos, additional, Poston, Michael J., additional, Sori, Mike, additional, Delitsky, Mona, additional, Pinilla-Alonso, Noemi, additional, Schorghofer, Norbert, additional, Prem, Parvathy, additional, Byrne, Paul, additional, Hayne, Paul, additional, Lucey, Paul, additional, James, Peter, additional, Pokorny, Petr, additional, Jr., Ronald J. Vervack,, additional, Killen, Rosemary, additional, Potter, Ross, additional, Solomon, Sean, additional, Shukla, Shashwat, additional, Bhiravarasu, Sriram, additional, Hauck, Steven, additional, Orlando, Thomas, additional, Stubbs, Timothy, additional, Bickel, Valentin, additional, Eke, Vincent, additional, and Farrell, William, additional

Published
2021
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29. Lunar Volatiles and Solar System Science

Author

Prem, Parvathy, primary, Kereszturi, Ákos, additional, Deutsch, Ariel N., additional, Hibbitts, Charles A., additional, Schmidt, Carl A., additional, Grava, Cesare, additional, Honniball, Casey I., additional, Hardgrove, Craig J., additional, Pieters, Carlé M., additional, Goldstein, David B., additional, Barker, Donald C., additional, Needham, Debra H., additional, Hurley, Dana M., additional, Mazarico, Erwan, additional, Dominguez, Gerardo, additional, Patterson, G. Wesley, additional, Kramer, Georgiana Y., additional, Brisset, Julie, additional, Gillis-Davis, Jeffrey J., additional, Mitchell, Julie L., additional, Szalay, Jamey R., additional, Halekas, Jasper S., additional, Keane, James T., additional, Head, James W., additional, Mandt, Kathleen E., additional, Robinson, Katharine L., additional, Luchsinger, Kristen M., additional, Magaña, Lizeth O., additional, Siegler, Matthew A., additional, Landis, Margaret E., additional, Poston, Michael J., additional, Petro, Noah E., additional, Lucey, Paul G., additional, Killen, Rosemary M., additional, Li, Shuai, additional, Narendranath, Shyama, additional, Shukla, Shashwat, additional, Barrett, Thomas J., additional, Stubbs, Timothy J., additional, Orlando, Thomas M., additional, and Farrell, William M., additional

Published
2021
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30. Understanding and Mitigating Plume Effects During Powered Descents on the Moon and Mars

Author

Watkins, Ryan, primary, Metzger, Philip T., additional, Mehta, Manish, additional, Han, Daoru, additional, Prem, Parvathy, additional, Sibille, Laurent, additional, Dove, Adrienne, additional, Jolliff, Bradley, additional, III, Daniel P. Moriarty,, additional, Barker, Donald C., additional, Patrick, Ed, additional, Kuhns, Matthew, additional, Laine, Michael, additional, and Radley, Charles F., additional

Published
2021
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32. Lunar Volatiles and Solar System Science

Author

Prem, Parvathy, Kereszturi, Ákos, Deutsch, Ariel N., Hibbitts, Charles A., Schmidt, Carl A., Grava, Cesare, Honniball, Casey I., Hardgrove, Craig J., Pieters, Carlé M., Goldstein, David B., Barker, Donald C., Needham, Debra H., Hurley, Dana M., Mazarico, Erwan, Dominguez, Gerardo, Patterson, G. Wesley, Kramer, Georgiana Y., Brisset, Julie, Gillis-Davis, Jeffrey J., Mitchell, Julie L., Szalay, Jamey R., Halekas, Jasper S., Keane, James T., Head, James W., Mandt, Kathleen E., Robinson, Katharine L., Luchsinger, Kristen M., Magaña, Lizeth O., Siegler, Matthew A., Landis, Margaret E., Poston, Michael J., Petro, Noah E., Lucey, Paul G., Killen, Rosemary M., Li, Shuai, Narendranath, Shyama, Shukla, Shashwat, Barrett, Thomas, Stubbs, Timothy J., Orlando, Thomas M., Farrell, William M., Prem, Parvathy, Kereszturi, Ákos, Deutsch, Ariel N., Hibbitts, Charles A., Schmidt, Carl A., Grava, Cesare, Honniball, Casey I., Hardgrove, Craig J., Pieters, Carlé M., Goldstein, David B., Barker, Donald C., Needham, Debra H., Hurley, Dana M., Mazarico, Erwan, Dominguez, Gerardo, Patterson, G. Wesley, Kramer, Georgiana Y., Brisset, Julie, Gillis-Davis, Jeffrey J., Mitchell, Julie L., Szalay, Jamey R., Halekas, Jasper S., Keane, James T., Head, James W., Mandt, Kathleen E., Robinson, Katharine L., Luchsinger, Kristen M., Magaña, Lizeth O., Siegler, Matthew A., Landis, Margaret E., Poston, Michael J., Petro, Noah E., Lucey, Paul G., Killen, Rosemary M., Li, Shuai, Narendranath, Shyama, Shukla, Shashwat, Barrett, Thomas, Stubbs, Timothy J., Orlando, Thomas M., and Farrell, William M.

33. Lunar Volatiles and Solar System Science

Author

Prem, Parvathy, Kereszturi, Ákos, Deutsch, Ariel N., Hibbitts, Charles A., Schmidt, Carl A., Grava, Cesare, Honniball, Casey I., Hardgrove, Craig J., Pieters, Carlé M., Goldstein, David B., Barker, Donald C., Needham, Debra H., Hurley, Dana M., Mazarico, Erwan, Dominguez, Gerardo, Patterson, G. Wesley, Kramer, Georgiana Y., Brisset, Julie, Gillis-Davis, Jeffrey J., Mitchell, Julie L., Szalay, Jamey R., Halekas, Jasper S., Keane, James T., Head, James W., Mandt, Kathleen E., Robinson, Katharine L., Luchsinger, Kristen M., Magaña, Lizeth O., Siegler, Matthew A., Landis, Margaret E., Poston, Michael J., Petro, Noah E., Lucey, Paul G., Killen, Rosemary M., Li, Shuai, Narendranath, Shyama, Shukla, Shashwat, Barrett, Thomas, Stubbs, Timothy J., Orlando, Thomas M., Farrell, William M., Prem, Parvathy, Kereszturi, Ákos, Deutsch, Ariel N., Hibbitts, Charles A., Schmidt, Carl A., Grava, Cesare, Honniball, Casey I., Hardgrove, Craig J., Pieters, Carlé M., Goldstein, David B., Barker, Donald C., Needham, Debra H., Hurley, Dana M., Mazarico, Erwan, Dominguez, Gerardo, Patterson, G. Wesley, Kramer, Georgiana Y., Brisset, Julie, Gillis-Davis, Jeffrey J., Mitchell, Julie L., Szalay, Jamey R., Halekas, Jasper S., Keane, James T., Head, James W., Mandt, Kathleen E., Robinson, Katharine L., Luchsinger, Kristen M., Magaña, Lizeth O., Siegler, Matthew A., Landis, Margaret E., Poston, Michael J., Petro, Noah E., Lucey, Paul G., Killen, Rosemary M., Li, Shuai, Narendranath, Shyama, Shukla, Shashwat, Barrett, Thomas, Stubbs, Timothy J., Orlando, Thomas M., and Farrell, William M.

34. DSMC simulations of volatile transport in a transient lunar atmosphere and ice deposition in cold traps after a comet impact

Author

Prem, Parvathy

Subjects
DSMC, Moon, Volatiles, Comet impacts, Transient lunar atmosphere, Ice deposition, Cold traps, Lunar water transport, Lunar water sequestration, Lunar comet impacts, Impact-delivered volatiles, Volatile-rich impact, Lunar atmosphere, Lunar impact simulations, Antipodal vapor, Lunar water distribution, Lunar rough surface temperature model, Lunar radiative heat transfer, Lunar impact-delivered water
Abstract

Over the years, a number of missions have detected signs of water and other volatiles in cold, permanently shadowed regions near the lunar poles, where temperatures are sufficiently low that volatile ices can remain stable over geological timescales. Several observations suggest that comet impacts may have played a role in delivering these cold-trapped volatiles. In this work, I use Direct Simulation Monte Carlo (DSMC) simulations to investigate the transport and sequestration of water in the aftermath of a lunar comet impact, focusing on developing a broad understanding of the physical processes that govern the fate of impact-delivered volatiles (particularly water), in order to better interpret remote sensing data. The sheer amount of vapor generated by a volatile-rich impact can transform the Moon’s tenuous, surface-bound exosphere into a collisional, transient atmosphere with characteristic gas dynamic features that influence the redistribution of impact-delivered volatiles. Notably, the simulations indicate that reconvergence of vapor antipodal to the point of impact may result in preferential redistribution of water in the vicinity of the antipode; in some circumstances, water may be distributed non-uniformly between different cold traps. It is also found that atmospheric self-shielding from photodestruction significantly increases the amount of water that reaches the shelter of cold traps. Volatile transport in an impact-generated atmosphere is also influenced by gas phase interactions with solar radiation and the lunar surface. The Moon has a distinctive surface thermal environment, characterized by large gradients in temperature over very small scales. In this work, I develop a stochastic rough surface temperature model that is then coupled to volatile transport simulations. It is found that surface roughness reduces the mobility of water at high latitudes, while also increasing the concentration of atmospheric/exospheric water molecules around the poles. I also implement a coupled DSMC-photon Monte Carlo method to model radiative heat transfer in the evolving, three-dimensional, rarefied atmosphere. The trapping of radiation within the optically thick gas slows the rate of cooling of the expanding vapor cloud, and also affects near-field atmospheric structure and winds. Ultimately, the fate of impact-delivered water is determined by the interplay between these factors.

Published
2017

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