Browsing by Author "Ernst, Carolyn M."
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Item Achievement of the Planetary Defense Investigations of the Double Asteroid Redirection Test (DART) Mission(AAS, 2024-02-26) Chabot, Nancy L.; Rivkin, Andrew S.; Cheng, Andrew F.; Barnouin, Olivier S.; Fahnestock, Eugene G.; Richardson, Derek C.; Stickle, Angela M.; Thomas, Cristina A.; Ernst, Carolyn M.; Daly, R. Terik; Dotto, Elisabetta; Zinzi, Angelo; Chesley, Steven R.; Moskovitz, Nicholas A.; Barbee, Brent W.; Abell, Paul; Agrusa, Harrison F.; Bannister, Michele T.; Beccarelli, Joel; Bekker, Dmitriy L.; Syal, Megan Bruck; Buratti, Bonnie J.; Busch, Michael W.; Bagatin, Adriano Campo; Chatelain, Joseph P.; Chocron, Sidney; Collins, Gareth S.; Conversi, Luca; Davison, Thomas M.; DeCoster, Mallory E.; Deshapriya, J. D. Prasanna; Eggl, Siegfried; Espiritu, Raymond C.; Farnham, Tony L.; Ferrais, Marin; Ferrari, Fabio; F�hring, Dora; Fuentes-Mu�oz, Oscar; Gai, Igor; Giordano, Carmine; Glenar, David; Gomez, Edward; Graninger, Dawn M.; Green, Simon F.; Greenstreet, Sarah; Hasselmann, Pedro H.; Herreros, Isabel; Hirabayashi, Masatoshi; Hus�rik, Marek; Ieva, Simone; Ivanovski, Stavro L.; Jackson, Samuel L.; Jehin, Emmanuel; Jutzi, Martin; Karatekin, Ozgur; Knight, Matthew M.; Kolokolova, Ludmilla; Kumamoto, Kathryn M.; K�ppers, Michael; Forgia, Fiorangela La; Lazzarin, Monica; Li, Jian-Yang; Lister, Tim A.; Lolachi, Ramin; Lucas, Michael P.; Lucchetti, Alice; Luther, Robert; Makadia, Rahil; Epifani, Elena Mazzotta; McMahon, Jay; Merisio, Gianmario; Merrill, Colby C.; Meyer, Alex J.; Michel, Patrick; Micheli, Marco; Migliorini, Alessandra; Minker, Kate; Modenini, Dario; Moreno, Fernando; Murdoch, Naomi; Murphy, Brian; Naidu, Shantanu P.; Nair, Hari; Nakano, Ryota; Opitom, Cyrielle; Orm�, Jens; Owen, J. Michael; Pajola, Maurizio; Palmer, Eric E.; Palumbo, Pasquale; Panicucci, Paolo; Parro, Laura M.; Pearl, Jason M.; Penttil�, Antti; Perna, Davide; Petrescu, Elisabeta; Pravec, Petr; Raducan, Sabina D.; Ramesh, K. T.; Ridden-Harper, Ryan; Rizos, Juan L.; Rossi, Alessandro; Roth, Nathan X.; Ro?ek, Agata; Rozitis, Benjamin; Ryan, Eileen V.; Ryan, William H.; S�nchez, Paul; Santana-Ros, Toni; Scheeres, Daniel J.; Scheirich, Peter; Senel, Cem Berk; Snodgrass, Colin; Soldini, Stefania; Souami, Damya; Statler, Thomas S.; Street, Rachel; Stubbs, Timothy J.; Sunshine, Jessica M.; Tan, Nicole J.; Tancredi, Gonzalo; Tinsman, Calley L.; Tortora, Paolo; Tusberti, Filippo; Walker, James D.; Waller, C. Dany; W�nnemann, Kai; Zannoni, Marco; Zhang, YunNASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by -33.24 minutes, with two independent analysis methods each reporting a 1σ uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, β, resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the Didymos?Dimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense.Item Science Goals and Mission Concept for a Landed Investigation of Mercury(IOP Science, 2022-03-25) Ernst, Carolyn M.; Chabot, Nancy L.; Klima, Rachel L.; Kubota, Sanae; Goossens, Sander; et alMercury holds valuable clues to the distribution of elements at the birth of the solar system and how planets form and evolve in close proximity to their host stars. This Mercury Lander mission concept returns in situ measurements that address fundamental science questions raised by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission's pioneering exploration of Mercury. Such measurements are needed to understand Mercury's unique mineralogy and geochemistry, characterize the proportionally massive core's structure, measure the planet's active and ancient magnetic fields at the surface, investigate the processes that alter the surface and produce the exosphere, and provide ground truth for remote data sets. The mission concept achieves one full Mercury year (∼88 Earth days) of surface operations with an 11-instrument, high-heritage payload delivered to a landing site within Mercury's widely distributed low-reflectance material, and it addresses science goals encompassing geochemistry, geophysics, the Mercury space environment, and geology. The spacecraft launches in 2035, and the four-stage flight system uses a solar electric propulsion cruise stage to reach Mercury in 2045. Landing is at dusk to meet thermal requirements, permitting ∼30 hr of sunlight for initial observations. The radioisotope-powered lander continues operations through the Mercury night. Direct-to-Earth communication is possible for the initial 3 weeks of landed operations, drops out for 6 weeks, and resumes for the final month. Thermal conditions exceed lander operating temperatures shortly after sunrise, ending operations. Approximately 11 GB of data are returned to Earth. The cost estimate demonstrates that a Mercury Lander mission is feasible and compelling as a New Frontiers–class mission.