Publications

A combination of several measurement techniques was used to investigate the dielectric properties of 80 rock samples in the microwave region. The real part of the dielectric constant, epsilon', was measured in 0.1 GHz steps from 0.5 to 18 GHz, and the imaginary part, epsilon'', was measured at five frequencies extending between 1.6 and 16 GHz. In addition to the dielectric measurements, the bulk density was measured for all the samples and the bulk chemical composition was determined for 56 of the samples. The study shows that epsilon' is frequency-dependent over the 0.5 to 18 GHz range for all rock samples, and that the bulk density rho accounts for about 50 percent of the observed variance of epsilon'. For individual rock types (by genesis), about 90 percent of the observed variance may be explained by the combination of density and the fractional contents of SiO2, Fe2O3, MgO, and TiO2. For the loss factor epsilon'', it was not possible to establish statistically significant relationships between it and the measured properties of the rock samples (density and chemical composition).

Organizers: Lunar and Planetary Institute, Universities Space Research Association ; Conveners: Richard Soare, Dawson College, Steve Clifford, Planetary Science Institute, Susan Conway, Laboratoire de Planetologie et Geodynamique-CNRS, Jim Garvin, NASA Goddard Space Flight Center, Ernst Hauber, German Aerospace Centre, Institute of Planetary Research.

The selection of three new missions to Venus opens a new era to explore the planet and its evolution: ESA’s EnVision and NASA’s VERITAS and DAVINCI missions plan to observe Venus in the next decade. ESA and NASA established a joint Venus Science Coordination group (VeSCoor) as a forum for dialogue within the broader Venus scientific community, in support of the upcoming ESA and NASA missions to Venus [1].The NASA VERITAS mission will study the surface and interior with an interferometric synthetic aperture radar and infrared instrument that provide global topography, imaging, rock type, and targeted surface deformation, plus radio science for interior structure [2].The NASA DAVINCI mission a descent probe that will determine the composition and history of Venus’ atmosphere as well as make additional measurements of the planet’s surface and atmosphere. DAVINCI consists of a spacecraft hosting a carrier and a descent probe, with seven in-situ, imager and spectrometer instruments [3].EnVision, an ESA orbital mission in collaboration with NASA, will simultaneously investigate Venus’ history, activity and climate, from its inner core, to its surface, and further up to its upper atmosphere. EnVision’s science payload consists of five instruments (radar, spectrometers, sounding radar and radio science experiment) [4].These missions will offer unprecedented complementary views of Venus and determine fundamental characteristics of the planet and its long term evolution [5, 6].In this scenario, VeSCoor’s primary goals are to identify new, unanticipated scientific approaches and outcomes based on synergies among the missions to Venus and suggest studies to enhance overall scientific return. However, VeSCoor will not evaluate or propose changes to the current mission profiles, scientific objectives, or requirements.The group was initially made up of 12 members from the Venus science community (Figure 1), 6 selected by ESA and 6 by NASA, plus 3 representatives of the EnVision, VERITAS and DAVINCI missions [7]. Membership in VesCoor is initially set to a 2 year term, but may be renewed at the discretion of NASA and ESA. A scientific observer from South Korea has subsequently joined the group along with two members selected by JAXA.VeSCoor members’ expertises cover different scientific disciplines to provide a comprehensive view of Venus as a planet, and hence, as a complex system.Representatives from NASA and ESA agencies are involved as observers to provide support to the group’s activities.The Group meets in-person twice a year to discuss science objectives and receive updates on the missions’ development. The outcomes of the discussion will be part of public documents available soon. Three working groups (Interiors, Surfaces, and Atmospheres) have been created to address the identified topics, and to discuss specific actions that could facilitate progress in advance of the missions.The first in-person meeting was held in February 2024 in Virginia, USA (Figure 2). Mission representatives from VERITAS, EnVision, and DAVINCI presented descriptions of mission science payloads, timelines, expected science returns, and current activities. VeSCoor members worked on developing the "Rules of the Road" document that establishes rules of conduct and communication.The second in-person meeting of VeSCoor was held in the ESA ESTEC establishment on November 2024 (Figure 3). We included in the discussion the Earth-based observation of Venus and talked about the Korean earth-based satellite for Venus exploration (CLOVE) [8].To improve the scientific discussion, four speakers were invited to present specific topics identified by the Group as strategic:- Sara Seager presented the ‘The search for life in the Venus’ clouds’ goal of the Morning Star mission.- Sebastien Lebonnois presented a review on the Venus Global Climate Models.- Edgar Steenstra talked about his recent laboratory set up to support the EnVision observations.- Lorenzo Bruzzone, PI of the radar Sounder SRS onboard EnVision presented the objectives and foreseen capabilities of this instrument to explore the subsurface of Venus.The third in-person meeting of VeSCoor was again held at the Lansdowne Resort in Leesburg in March of 2025 (Figure 4). The group received updates on NASA developments from Delia Santiago-Matarese, and status reports from EnVision, VERITAS, and DaVinci mission leadership. Three speakers were invited this time:- David Grinspoon (NASA’s Senior Scientist for Astrobiology Strategy) discussed the Astrobiological Potential of Venus.- Michael Chaffin presented the Photochemical Hydrogen Loss from Venus and the Fate of an Earth-like Water Inventory.- Debra Buczkowski described the status of the Venus Geologic Mapping Efforts.The preliminary results of the discussion emphasize the importance of on-going studies and experimental work in preparation for the new missions.The importance of completing the Venus mapping programme and generating ongoing discussion on common mapping standards for the international Venus community was emphasized. Also, facilitation of analog field studies to test the instrument performance, operational routine and scientific data integration was supported.International collaboration is fundamental to unite the efforts for successful exploration of Venus.The Group also discussed the need to establish workshops for the international Venus community (COSPAR, etc.) and maintain contact with other Venus-focused groups (i.e., VEXAG).Acknowledgments:The Group would like to express their thanks to ESA and NASA representatives for supporting our activities and particularly to Ramon De Paula who has recently retired from NASA.References: [1] NASA-ESA Venus Science Coordination (VeSCoor) – Terms of Reference 2022, [2] Smrekar, S.E. et al. (2022) In: 2022 IEEE aerospace conference; [3] Garvin, J.B. et al. (2022) Planet Sci J 3:117; [4] ESA, EnVision Definition Study Report, ESA-SCI-DIR-RP-003(2023); [5] O’Rourke, J., et al. Space Sci Rev 219, 10 (2023); [6] Widemann, T., et al. Space Sci Rev 219, 56 (2023); [7] https://www.cosmos.esa.int/web/envision/vescoor-page ; [8] Lee, Y.J. (2024) EPSC doi:10.5194/epsc2024-158 . Figure 1. 2023-25 VeSCoor members and expertises.Figure 2. VeSCoor first in person meeting in Lansdowne Resort, Leesburg, VA, USA, February 28-March 1 2024.Figure 3. VeSCoor members working during the second in person meeting in ESA ESTEC (Nov. 5-7, 2024).Figure 4. VeSCoor third in person meeting in Lansdowne Resort, Leesburg, VA, USA, March 25-27 2025.

We summarize a proposed experiment to use the International Space Station to formally examine the application and validation of low-latency telepresence for surface exploration from space as an alternative, precursor, or potentially as an adjunct to astronaut boots on the ground. The approach is to develop and propose controlled experiments, which build upon previous field studies and which will assess the effects of different latencies (0 to 500 msec), task complexity, and alternate forms of feedback to the operator. These experiments serve as an example of a pathfinder for NASA's roadmap of missions to Mars with low-latency telerobotic exploration as a precursor to astronaut's landing on the surface to conduct geological tasks.

We use measurements from the Lunar Exploration Neutron Detector (LEND) collimated sensors during more than one year of the mapping phase of NASA's Lunar Reconnaissance Orbiter (LRO) mission to make estimates of the epithermal neutron flux within known large Permanently Shadowed Regions (PSRs). These are compared with the local neutron background measured outside PSRs in sunlit regions. Individual and collective analyses of PSR properties have been performed. Only three large PSRs, Shoemaker and Cabeus in the south and Rozhdestvensky U in the north, have been found to manifest significant neutron suppression. All other PSRs have much smaller suppression, only a few percent, if at all. Some even display an excess of neutron emission in comparison to the sunlit vicinity around them. Testing PSRs collectively, we have not found any average suppression for them. Only the group of 18 large PSRs, with area >200 km 2 , show a marginal effect of small average suppression, ∼2%, with low statistical confidence. A ∼2% suppression corresponds to ∼125 ppm of hydrogen taking into account the global neutron suppression near the lunar poles and assuming a homogeneous H distribution in depth in the regolith. This means that all PSRs, except those in Shoemaker, Cabeus and Rozhdestvensky U craters, do not contain any significant amount of hydrogen in comparison with sunlit areas around them at the same latitude.