scholarly journals High‐resolution local gravity model of the south pole of the Moon from GRAIL extended mission data

2014 ◽  
Vol 41 (10) ◽  
pp. 3367-3374 ◽  
Author(s):  
Sander Goossens ◽  
Terence J. Sabaka ◽  
Joseph B. Nicholas ◽  
Frank G. Lemoine ◽  
David D. Rowlands ◽  
...  
2021 ◽  
Author(s):  
Athena Coustenis ◽  
Donald Jennings ◽  
Richard Achterberg ◽  
Panayotis Lavvas ◽  
Conor Nixon ◽  
...  

<p>Titan is a unique body in the solar system in particular because of its earth-like surface features, its putative undersurface liquid water ocean and its large organic content in the atmosphere and on the surface . These chemical species evolve with season, as Titan follows Saturn in its orbit around the Sun with an inclination of about 27°. We performed an analysis of spectra acquired by Cassini/CIRS at high resolution covering the range from 10 to 1500 cm<sup>-1</sup> since the beginning and until the last flyby of Titan in 2017 and describe the temperature and composition variations ([1-3]. By applying our radiative transfer code (ARTT) to the high-resolution CIRS spectra we study the stratospheric evolution over almost two Titan seasons [1,2]. CIRS nadir and limb spectral together show variations in temperature and chemical composition in the stratosphere during the Cassini mission, before and after the Northern Spring Equinox (NSE) and also during one Titan year.</p><p>Since the 2010 equinox we have thus reported on monitoring of Titan’s stratosphere near the poles and in particular on the observed strong temperature decrease and compositional enhancement above Titan’s southern polar latitudes since 2012 and until 2014 of several trace species, such as complex hydrocarbons and nitriles, which were previously observed only at high northern latitudes. This effect followed the transition of Titan’s seasons from northern winter in 2002 to northern summer in 2017, while at that latter time the southern hemisphere was entering winter.</p><p>Our data show a continued decrease of the abundances which we first reported to have started in 2015. The 2017 data we have acquired and analyzed here are important because they are the only ones recorded since 2014 close to the south pole in the far-infrared nadir mode at high resolution. A large temperature increase in the southern polar stratosphere (by 10-50 K in the 0.5 mbar-0.05 mbar pressure range) is found and a change in the temperature profile’s shape. The 2017 observations also show a related significant decrease in most of the abundances which must have started sometime between 2014 and 2017 [3]. In our work, we show that the equatorial latitudes remain rather constant throughout the Cassini mission.</p><p>We have thus shown that the south pole of Titan is now losing its strong enhancement, while the north pole also slowly continues its decrease in gaseous opacities. It would have been interesting to see when this might happen, but the Cassini mission ended in September 2017. Perhaps future ground-based measurements and the Dragonfly mission can pursue this investigation and monitor Titan’s atmosphere to characterize the seasonal events. Our results set constraints on GCM and photochemical models.</p><p>References:</p><p> [1] Coustenis et al., 2016, Icarus 270, 409-420; [2] Coustenis et al., 2018, Astroph. J., Lett., 854, no2; [3] Coustenis et al., 2020. Titan’s neutral atmosphere seasonal variations up to the end of the Cassini mission. Icarus 344, 113413. https://doi.org/10.1016/j.icarus.2019.113413.</p>


2014 ◽  
Vol 41 (8) ◽  
pp. 2738-2745 ◽  
Author(s):  
Makiko Ohtake ◽  
Kisara Uemoto ◽  
Yasuhiro Yokota ◽  
Tomokatsu Morota ◽  
Satoru Yamamoto ◽  
...  

1988 ◽  
Vol 93 (D6) ◽  
pp. 7069-7074 ◽  
Author(s):  
Aaron Goldman ◽  
Frank J. Murcray ◽  
Frank H. Murcray ◽  
David G. Murcray ◽  
Curtis P. Rinsland

2009 ◽  
Vol 36 (22) ◽  
Author(s):  
Ryosuke Nakamura ◽  
Tsuneo Matsunaga ◽  
Yoshiko Ogawa ◽  
Satoru Yamamoto ◽  
Takahiro Hiroi ◽  
...  
Keyword(s):  
The Moon ◽  

Author(s):  
Buddhadev Sarkar ◽  
Pabitra Kumar Mani

Aims: The Chandrayaan-2 aims to wave the Indian flag on the dark side (South Pole) of the Moon that had never been rendered by any country before. The mission had conducted to gather more scientific information about the Moon. There were three main components of the Chandrayann-2 spacecraft- an orbiter, a lander, and a rover, means to collect data for the availability of water in the South Pole of the Moon. Place and Duration of Study: The rover (Pragyan) was designed to operate for one Lunar day that is equivalent to 14 Earth days, whereas the orbiter is assumed to orbit the Moon for seven years instead of the previously planned for just one year. Overview: The Chandrayaan-2 spacecraft launched by India's heavy-lift rocket Geosynchronous Satellite Launch Vehicle-Mark III (GSLV MKIII) from the Satish Dhawan Space Center launch pad located on Sriharikota island of Andhra Prades. Unlike, Chandrayaan-1, this lunar mission aimed to perform a soft-landing on the South Pole of the Lunar surface and do scientific experiments with the help of the rover (Pragyan). Reason: The Chandrayaan-1, the first lunar mission of ISRO that detected water molecules on the Moon. The Chandrayaan-2 was a follow-on mission of Chandrayaan-1 to explore the presence of water molecules on the South Pole of the Moon. Conclusion: Although the orbiter fulfilled all of the command, unfortunately, the lander (Lander) lost its communication at the last moment to touch the Moon’s surface softly. Despite that, India again showed its potential in space missions. Chandrayaan- 2 was the most low budget lunar mission ever conducted by any space organization. The developing or even underdeveloped countries may come forward in their space program as ISRO is showing a convenient way in space missions.


2021 ◽  
Author(s):  
Marine Joulaud ◽  
Jessica Flahaut ◽  
Diego Urbina ◽  
Hemanth K. Madakashira ◽  
Gen Ito ◽  
...  

<p>Lunar volatiles, such as water, are a crucial resource for future exploration, and their exploitation should enable the use of the Moon as a platform for even more remote destinations. As water is most likely to be found in the form of ice at the lunar poles (where surface temperatures can be as low as 40K, i.e. below the H2O temperature of sublimation in vacuum, 110K), multiple upcoming missions target the south pole (SP) cold traps. PSRs (Permanently Shadowed Regions) are especially cold enough to capture and retain volatiles but present challenging access conditions (rough topography, low illumination, low temperatures, limited Earth visibility).</p><p>Funded by the EU program Horizon 2020, Space Applications Services developed the LUVMI-X rover (LUnar Volatiles Mobile Instrument eXtended), aimed at sampling and analysing lunar volatiles in the polar regions, including within a PSR. The LUVMI-X nominal payload includes an instrumented drill, the Volatiles Sampler (VS), along with a mass spectrometer, the Volatiles Analyser (VA), for surface and subsurface volatile detection and characterisation. A LIBS and a radiation detector are also included. Deployable and propellable surface science payloads are in development for inaccessible sites (e.g., some of the PSRs). This solar-powered rover has an autonomy of one or two Earth nights and can drill down to 20cm in the lunar regolith. The goal of this paper is to find suitable landing sites & traverses’ paths for this rover project, that are both scientifically interesting and technically reachable.</p><p>Available remote sensing imagery for the lunar SP was downloaded from the PDS or corresponding instruments’ websites and added into a Geographic Information System (GIS). LUVMI-X scientific objectives and technical specifications were then translated into a list of criteria and computed in our GIS using reclassifications, buffers, and intersections. Using our GIS, reclassified data were overlaid with different weights to define and rank areas meeting the compulsory criteria. A global analysis was led to select the landing sites, followed by a local analysis (based on higher resolution data) for the establishment of traverses.</p><p>The global GIS analysis allowed us to identify six regions of interest (ROI), which were compared with previous SP ROI from the literature (Lemelin, 2014; Flahaut, 2020). The identified ROI were further ranked based on areas and statistics on Sun and Earth visibilities, Diviner average surface temperatures, and H/water ice signatures (LPNS, LEND, M3).</p><p>A prime ROI located between Shackleton and the Shoemaker/Faustini ridge was selected for traverse analysis. Four landing ellipses of 2x2km were located and ranked inside the ROI. Way Points (WP) were then identified to include the following scientific interests in each traverse: a boulder casting shadows, a PSR to throw a propellable payload in, an accessible PSR to go into, etc. As several WP are possible, Earth visibility was used to select the best ones. WP were then connected by using slope maps (LOLA DEM at 5m/px: avoid slopes over 20°), Earth & Sun visibilities (avoid no-go zones) and the LROC NAC mosaics at 1m/px (avoid boulders and craters), constituting a tentative traverse.</p>


1988 ◽  
Vol 98 ◽  
pp. 146-146
Author(s):  
Michel Legrand
Keyword(s):  
The Moon ◽  

AbstractA region of approximately 270 000 km2 near the south pole of the Moon has not been mapped by spacecraft and Dr John Westfall of ALPO proposed the “Luna Incognita” programme in 1972 to try to cover this area. A brief summary of the problems of observing this limb region was given, together with the author’s experience using the T60 and 1-m telescopes at Pic du Midi.


1979 ◽  
Author(s):  
Frank J. Murcray ◽  
Frank H. Murcray ◽  
David G. Murcray

2018 ◽  
Vol 123 (10) ◽  
pp. 2585-2612 ◽  
Author(s):  
M. A. Ivanov ◽  
H. Hiesinger ◽  
C. H. van der Bogert ◽  
C. Orgel ◽  
J. H. Pasckert ◽  
...  

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