Search

Kelvin–Helmholtz waves can be observed frequently at the near-Earth magnetopause and play an important role in the transport of particles, momentum, and energy from the solar wind to the magnetosphere. This work analyzes the occurrence of Kelvin–Helmholtz instability (KHI) at lunar distance magnetopause, which has not been thoroughly studied currently based on Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun satellite observations, and it also investigates the effect of the upstream solar wind and interplanetary magnetic field (IMF). Statistical results show that (1) the occurrence rate is about 15% of the time at lunar distance, lower than at the flank magnetopause, and (2) the occurrence rate decreases with the magnetoacoustic Mach number, Alfvén Mach number, solar wind velocity, and dynamic pressure but only shows a slightly positive correlation with solar wind density. Unlike at the dayside magnetopause, the occurrence rate of KHI diminishes as the solar wind velocity increases at the lunar distance magnetopause, and (3) the occurrence rate decreases with IMF amplitude and is influenced by IMF orientation. As a function of the IMF clock angle, the occurrence rate reaches its maximum at ∼24% when the clock angle is zero. The statistical results are basically consistent with the currently accepted linear theory of KHI, except for a lower rate for higher-speed solar wind. This work contributes to understanding the excitation and evolution of KHI along the magnetopause and plasma transport process in the tail magnetopause.

The Lawn Dart program, a proliferated mesh network of security commodities staged across the lunar surface, will promote a stable and sustainable space operating environment. Lawn Darts will deploy as probes from lunar orbit around the surface of the Moon to provide an Internet of Things and a power network for other operational assets such as rovers, people, and Moon bases. This capability and its execution raises questions about international law and geopolitical concerns related to territorial claims on the lunar surface and the planned organization of space activities by conflicting parties, but the program is compliant with the current framework of law and policy. The Lawn Dart program is essential for providing security for lunar assets, protecting mission data against adversaries, and laying the groundwork for NASA and European Space Agency exploration mission success. [ABSTRACT FROM AUTHOR]

The upcoming lunar Chang'e‐5 mission is scheduled to land near Mons Rümker, in northern Oceanus Procellarum, and return samples with masses up to 2 kg from depths up to ~2 m. A clear understanding of the regolith components in the candidate landing region is crucial to both the selection of sampling sites and the interpretation of the geological affinities for the returned samples. We quantitatively estimate the abundance of distantly sourced particles (DSPs) in the regolith at the landing region using an updated ballistic sedimentation model. Our results suggest that older units have a higher abundance of DSPs. In the targeted landing area, the total abundance of DSPs on the surface of the regolith varies from approximately 12% to 20%, and most of the DSPs on the surface are ejecta from the Pythagoras (~5%) and/or Aristarchus (~7%) craters. The youngest geological unit, which is located in the easternmost sector of the landing region, possesses the least DSPs in the regolith. Therefore, sampling the eastern unit has a higher potential of revealing both the petrological characteristics and age of the youngest mare basalt, which are fundamentally important to improve both the lunar crater chronology and the understanding of late‐stage evolution of the Moon. Our results also indicate that the anorthositic material within the shallow regolith is most likely ejected from the Pythagoras and Aristarchus craters, which could further improve the understanding of lunar geology and chronology. Plain Language Summary: Chang'e‐5 will be the first lunar sample return mission since the 1976 Luna 24 mission. It will return surface and core samples with masses up to 2 kg from depths up to ~2 m from northern Oceanus Procellarum. Most of the returned samples are expected to be lunar regolith. A better understanding of the regolith components in the candidate landing region is therefore helpful to both select sampling sites and interpret the samples that will be returned in the future. Here, we estimate the abundance of distantly sourced particles (DSPs) in the regolith within the proposed landing region. We find that older units are more enriched in DSPs, and the total surface abundance of DSPs varies from approximately 12% to 20%. Most DSPs on the surface are ejecta from the Pythagoras (~5%) and/or Aristarchus (~7%) craters. Our results support that the youngest mare unit is most suitable for sample return because of the low abundance of DSPs. Furthermore, core samples from this unit contain not only local basaltic materials and the several major sources of distant ejecta in the regolith but also both pristine highland anorthosites and pyroclastic deposits. Key Points: We estimate the abundance of distantly sourced particles in the regolith in the Chang'e‐5 candidate landing regionThe most abundant distantly sourced particles are ejecta from the craters Pythagoras and/or AristarchusIt is recommended to return samples from the youngest mare surface as there is a low abundance of distantly sourced particles [ABSTRACT FROM AUTHOR]

The article discusses information about amino acids provided by the Apollo lunar space program in the United States. It appears that the moon had a lawn of organic compounds that were destroyed by solar radiation. The findings from the moon have clarified another inference from the electric discharge experiments, which contained free amino acids at the end of the reaction. If the view is correct that the surface of the moon is baked-out with no residual organic compound of its own, the amino acid precursors represent the most complex known carbon compounds accumulated by an inert body in the solar system. The carbon compounds on the moon and in the meteorites have arisen by different cosmophysical processes.

The article comments on the theories of lunar formation and manned landings as basis about the origin of the moon. According to the author, manned lunar landing will yield information enabling investigators to decide between the other two theories, which is the theory of rotational breakup of the Earth and the capture theory. He also emphasizes that returned samples from the moon casts light on the first billion years of the Earth's history. In addition, the author also stresses that the data on the moon might give scientists a rise to a new and successful approach to the problem of the origin of the solar system.

The article comments on the resemblance between the discoveries in Columbia and moon landing by U.S. astronauts. According to the author, the purely scientific aspects of the project could not by themselves have commanded state support on any significant scale if it were not for the fact that both were tied at the hip-bone to political-economic-military aims. He stresses that eventhough there are certain resemblances, the Columbian discoveries and the Apollo program differ profoundly in many fundamental ways.

The article discusses several space program and problems regarding the origin of the moon. A professor suggested that the recent data from the Lunar Orbiter photo satellites and the Surveyor landers show that the moon has been colder and less plastic throughout its history than the Earth. The chemical composition of the Moon which was secured by surveyors V, VI, and VII constituted important data with regard to its surface. Various suggestions about the origin of the moon are also emphasized in the article.

The article focuses on the national goal of the U.S. to land Americans on the moon and returning them safely to earth. In order to reach this goal, the National Aeronautics and Space Administration on February 25, 1963, requested for the fiscal year beginning July 1, 1963 a budget of $5.7 billion, $2 billion more than for the previous fiscal year and $5 billion more than was spent on space during Dr. James Killian's tenure in the early days of the space age. Given the complexities of such vast endeavors, the National Aeronautics and Space Administration has already been planning ahead for missions beyond the lunar landing.

Abstract Returning to the Moon has kept gaining interest lately in the scientific community as a mandatory step for answering a cohort of key scientific questions. This paper presents a novel Lunar mission design to demonstrate enabling technologies for deep-space exploration, in accordance with the Global Exploration Roadmap and the National Research Council. This mission, named ALCIDES, takes advantage of some of the systems that are currently under development as a part of the HERACLES exploration architecture: these include the Orion module, the Space Exploration Vehicle, the Boeing Reusable Lander, the Ariane 6, the Falcon Heavy, the Space Launch System, as well as the Evolvable Deep-Space Habitat placed in EML2. A consistent part of the efforts in designing the ALCIDES mission accounts for innovative exploration scenarios: by analysing state of the art in robotics and planetary exploration, we introduce a mission architecture in which robots and humans collaborate to achieve several tasks, both autonomously and through cooperation. During this mission, high-performance mobility, extravehicular activity and habitation capabilities would be carried out and implemented. This project aims to demonstrate the human capability to live and work in the Lunar environment through the development of a long-term platform. We selected the Amundsen-Ganswindt basin as the landing site for multiple reasons: the possible presence of permanently shadowed regions, its position within the South Pole and its proximity to the Schrödinger basin. The main objectives of the ALCIDES mission are to study the Lunar cold trap volatiles, to gain understanding of the Lunar highlands geology through sampling and in-situ measurements and to study Human-Robotic interactions. In addition, factors such as psychology, legal issues and outreach regarding this mission were also considered. In particular, four traverses connecting the Amundsen crater with the Schrödinger basin were proposed, three of which to be performed by a tele-operated rover, and the remaining one to be carried out by a human crew with rover assistance. During these traverses, the rover will collect samples from several points of interest as well as perform in-situ measurements with a suite of instruments on board, helping to locate a convenient place for future human habitation. The ALCIDES mission results will help the scientific community to better understand the Moon and to take advantage of its resources for future space exploration. Gaining this knowledge will allow us to move forward in the development of systems and capabilities for manned missions to Mars and beyond. Highlights • International collaboration is a key point for ambitious space programs. • Human-Robot interaction is crucial for mission success and increasing performance. • Scientific goals should be the main objectives of space exploration missions. • Technologies to allow Lunar long-term research base are soon to be available. [ABSTRACT FROM AUTHOR]

The objective of this work is the preliminary design of a low-ΔV transfer from an initial elliptical orbit around Jupiter into a final circular orbit around the moon Europa. This type of trajectory represents an excellent opportunity for a low-cost mission to Europa, accomplished through a small orbiter, as in the proposed Europa Tomography Probe mission, a European contribution to NASA’s Europa Multiple-Flyby Mission (or Europa Clipper). The mission strategy is based on the v∞ leveraging concept, and the use of resonant orbits to exploit multiple gravity-assist from the moon. Possible sequences of resonant orbits are selected with the help of the Tisserand graph. Suitable trajectories are provided by an optimization code based on the parallel running of several differential evolution algorithms. Different solutions are finally compared in terms of propellant consumption and flight time. [ABSTRACT FROM AUTHOR]

The article discusses about the major problems in space and scientific exploration programs in the U.S. In this report, authors Philip M. Smith and Rodney W. Johnson emphasizes the goals of the lunar and Antarctic exploration. The authors believe that comparison of the lunar exploration program with the Antarctic exploration will yield a number of analogies, primarily in terms of how such an activity might most logically proceed. Furthermore, they indicated that science in both explorations have similar objectives, with each focusing on the geosciences.

The Chang'e-3 (CE-3) spacecraft successfully landed on one of the youngest mare surfaces on the Moon in December 2013. The Yutu rover carried by CE-3 was equipped with a radar system that could reveal subsurface structures in unprecedented details, which would facilitate understanding regional and global evolutionary history of the Moon. Based on regional geology, cratering scaling, and morphological study, here we quantify the subsurface structures of the landing site using high-resolution orbital and in-situ imagery data. Three layers of lunar regolith, two layers of basalt units, and one layer of ejecta deposits are recognized at the subsurface of the landing site, and their thicknesses are deduced based on the imagery data. These results could serve as essential references for the on-going interpretation of the CE-3 radar data. The ability to validate our theoretical subsurface structure using CE-3 in-situ radar observations will improve the methods for quantifying lunar subsurface structure using crater morphologies and scaling. [ABSTRACT FROM AUTHOR]

The Lunar Reconnaissance Orbiter Camera (LROC) includes two identical Narrow Angle Cameras (NAC) that acquire meter scale imaging. Stereo observations are acquired by imaging from two or more orbits, including at least one off-nadir slew. Digital terrain models (DTMs) generated from the stereo observations are controlled to Lunar Orbiter Laser Altimeter (LOLA) elevation profiles. With current processing methods, digital terrain models (DTM) have absolute accuracies commensurate than the uncertainties of the LOLA profiles (~10 m horizontally and ~1 m vertically) and relative horizontal and vertical precisions better than the pixel scale of the DTMs (2 to 5 m). The NAC stereo pairs and derived DTMs represent an invaluable tool for science and exploration purposes. We computed slope statistics from 81 highland and 31 mare DTMs across a range of baselines. Overlapping DTMs of single stereo sets were also combined to form larger area DTM mosaics, enabling detailed characterization of large geomorphic features and providing a key resource for future exploration planning. Currently, two percent of the lunar surface is imaged in NAC stereo and continued acquisition of stereo observations will serve to strengthen our knowledge of the Moon and geologic processes that occur on all the terrestrial planets. [ABSTRACT FROM AUTHOR]

The Chang’E-5 mission is the third phase of the Chinese Lunar Exploration Program and will collect and return lunar samples. After sampling, the Orbiter and the ascent vehicle will rendezvous and dock, and both spacecraft will require high precision orbit navigation. In this paper, we present a novel tracking mode—Four-way lunar Lander–Orbiter tracking that possibly can be employed during the Chang’E-5 mission. The mathematical formulas for the Four-way lunar Lander–Orbiter tracking mode are given and implemented in our newly-designed lunar spacecraft orbit determination and gravity field recovery software, the LUnar Gravity REcovery and Analysis Software/System (LUGREAS). The simulated observables permit analysis of the potential contribution Four-way lunar Lander–Orbiter tracking could make to precision orbit determination for the Orbiter. Our results show that the Four-way lunar Lander–Orbiter Range Rate has better geometric constraint on the orbit, and is more sensitive than the traditional two-way range rate that only tracks data between the Earth station and lunar Orbiter. After combining the Four-way lunar Lander–Orbiter Range Rate data with the traditional two-way range rate data and considering the Lander position error and lunar gravity field error, the accuracy of precision orbit determination for the Orbiter in the simulation was improved significantly, with the biggest improvement being one order of magnitude, and the Lander position could be constrained to sub-meter level. This new tracking mode could provide a reference for the Chang’E-5 mission and have enormous potential for the positioning of future lunar farside Lander due to its relay characteristic. [ABSTRACT FROM AUTHOR]