Apollo Missions Research Articles

Space Travel: The Radiation and Microgravity Effects on the Cardiovascular System.

Space flight modulates the functions of the cardiovascular system. The exposure to space conditions can alter the cerebral blood flow, as well as the venous return. Anemia, cardiac output changes, and increased activity of the sympathetic nervous system can also be seen. Understanding cardiac changes prepares astronauts for both better in-flight adaptations and long-term protection against cardiovascular diseases. The heart could undergo radio-degenerative effects when exposed to space radiation, increasing the risk of cardiovascular diseases in the long run. A high frequency of arrhythmias, such as ventricular/atrial premature complexes, have been reported during the Gemini and Apollo missions. Additionally, microgravity can lead to progressive degeneration of the myocytes and muscle atrophy with altered gene expression and calcium handling, along with impaired contractility. This review summarizes the potential cardiovascular effects of spaceflight and prevention measures.

Artificial Impacts on the Moon: Modeling 3D Seismic Propagation Effects with AxiSEM3D

During the Apollo missions, used spacecraft were deliberately crashed into the Moon to provide large signals for the seismic experiments. We use AxiSEM3D and a variety of 1D and 3D models to model these impacts and propagate seismic waves across the Moon in 3D. Simulations using a smoothly varying background model, which include scattering heterogeneities to 50 km depth, reproduced some of the observations, especially farther from the source. These simulations have an emergent onset and an increase and decay in the seismic envelope. However, close to the source (<15°), the simulations include a large-amplitude surface wave, which is inconsistent with the observations. Traditionally, artificial and meteoroid impacts on the Moon have been considered to have P and S phases. However, a true S phase may be absent. Previous authors have treated artificial or meteoroid impacts on airless bodies as explosions. A shear wave traveling directly from the source is not expected from an explosion. Instead, the small change of the slope of the seismic envelope may be explained by either a PS phase or scattered phases of P-to-SV conversions that start to dominate the seismogram. The locations of the artificial impacts are well known in comparison with other types of events. Due to their shallow paths, they are also ideal for constraining the near-surface layers. Understanding how the seismic waves propagate within the highly complex near-surface layers will also lead to a better understanding of how the waves propagate beneath them, as well as better results from future missions.

Assessment of toxicity changes induced by exposure of human cells to lunar dust simulant

The toxicity of lunar dust (LD) to astronauts' health has been confirmed in the Apollo missions and subsequent biological experiments. Therefore, it is crucial to understand the biological toxicity of lunar dust for future human missions to the Moon. In this study, we exposed human lung epithelial cells (BEAS-2B) and peripheral blood B lymphocytes (AHH-1) to varying concentrations (0, 500, 1000, and 1500 μg/ml) of a lunar dust simulant (LDS) called CLDS-i for 24 and 48 h. The results provided the following key findings: (1) LDS induction of cell damage occurred through oxidative stress, with the levels of reactive oxygen species (ROS) in BEAS-2B cells being dependent on the duration of exposure. (2) Necrosis and early apoptosis were observed in BEAS-2B cells and AHH-1 cells, respectively. In addition, both cells showed lysosomal damage. (3) Genes CXCL1, SPP1, CSF2, MMP1, and POSTN are implicated in immune response and cytoskeletal arrangement regulation in BEAS-2B cells. Considering the similarities in composition and properties between CLDS-i and real lunar dust, our findings not only enhance the understanding of LDS toxicity, but also contribute to a better comprehension of the genomic alterations and molecular mechanisms underlying cellular toxicity induced by LD. These insights will contribute to the development of a biotoxicology framework aimed at safeguarding the health of astronauts and, consequently, facilitating future human missions to the Moon.

Guidance, Navigation, and Control for the Moon, Mars, and Beyond

The interdisciplinary field known as Guidance, Navigation, and Control (GNC) has been one of the key contributors to the tremendous advancements in space exploration since the inception of the Mercury and Apollo programs [...]

Descriptive models for lunar High-Ti deposits

High-Ti deposits on the Moon may emerge as a key resource for oxygen extraction. Descriptive models are the first qualitative step toward quantitative assessments of natural resources. Such models provide a structured framework for understanding the formation processes and spatial distribution of discrete types of resource deposits. In this study, we provide the first lunar descriptive models, characterizing high-Ti lunar deposits, drawing parallels with established models used in assessing mineral deposits on Earth.Our methodology involves utilizing remote sensing datasets and geological maps to identify and describe high-Ti deposits. This is supplemented by data extrapolated from Apollo missions. However, there remain critical knowledge gaps, particularly regarding petrography, subsurface information, surface characteristics, and physical properties of high-Ti deposits, which necessitate further exploration and analysis.

Revisiting lunar dust charging and dynamics

Under the dynamic influence of near-surface plasma, intricate dynamics of lunar dust have been observed during the Surveyors and Apollo missions in the form of Lunar horizontal glow. These dynamics are primarily driven by electrostatic forces generated by the continual bombardment of solar wind and highly energetic UV photons on the lunar surface and dust particles. This paper revisits the phenomenon of dust charging within the lunar photoelectron sheath and subsequent dynamics. The investigation has been carried out using a comprehensive model of the lunar photoelectron sheath characterized by observed solar spectra, latitude-dependent Fermionic photoelectrons, non-Maxwellian solar wind electrons, and cold ions. A test dust particle is introduced into the sheath, and equilibrium charge and static levitation conditions are derived. The result of dynamical evolution suggests the existence of a narrow parametric regime corresponding to the periodic hopping trajectory of the dust particle over the lunar surface. In other cases, the dust particles are found to re-impact the surface after a single ballistic hop. We further identify that the discrete charging of the dust could be crucial in determining the dust dynamics, particularly in the tenuous plasmas. The analysis of the discrete dust charging model reveals significant discrepancies with the continuous dust charging model and suggests a lower likelihood of static dust levitation in the lunar environment. The present study is important for unraveling the fundamental processes governing surface evolution on the Moon and other airless bodies throughout the Solar System.

Geostratigraphic Mapping of the Intrusive Valentine Domes on the Moon

AbstractLunar intrusive igneous domes have not been the center of much research in the past due to their rare occurrence on the lunar surface, and the difficulty in locating them. Most of the known structures were discovered using images with low illumination angles, including data from the Lunar Orbiter, telescopic images, and photos taken during the Apollo Missions. These intrusive domes are characterized by an oval shape and low slopes. We analyzed one of these systems, the Valentine domes, located near the rim of the western Serenitatis basin, with modern techniques and data sets from the Lunar Reconnaissance Orbiter (LRO) and Chandrayaan‐1 missions. We created a geostratigraphic map of the area, combining geomorphological and spectral classifications. The aspect map (direction of the slope) proved to be the most suitable product to locate and delimit these structures; using it, we identified a new dome southeast of the principal body, suggesting that the intrusive system is larger than previously thought. It was found that the three domes can be classified as laccoliths, and that several derived structures such as rilles, dykes, and secondary domes represent different stages of intrusive activity in the area. Based on crater counting analysis, we determined that the intrusive activity began after 2.98 ± 0.15 Ga and lasted at least until 1.88 ± 0.5 Ga ago.

The Apollo Programme and its legacy

Abstract It is now over fifty years since the Apollo missions to the Moon. This paper briefly reviews the Apollo programme and its scientific legacy, and argues that science would benefit from a human return to the Moon.

Space travel across the decades and beyond: A brief history of NASA’s space programme

Abstract The National Aeronautics and Space Administration’s (NASA) journey into the cosmos is a captivating tapestry of milestones that have revolutionised our understanding of space. The intense competition in the early part of the Space Race between the US and Soviet space programmes fuelled rapid advancements in spacecraft technology, space science and interplanetary exploration strategies as both countries tried to be the first to put humans on the Moon. For NASA, human exploration began with the Mercury missions, followed by the Gemini missions proving humans could travel and work in space. The early pinnacle of NASA’s human space explorations came with the Apollo programme, which triumphantly made six historic lunar landings bringing back 382 kg of lunar material and leaving many important instruments on the Moon. Following the human Moon landings, NASA embraced space station missions with the marvel of engineering known as the Space Shuttle. This led to the assembly and maintenance of the International Space Station (ISS), a colossal orbiting laboratory hosting countless scientific experiments in microgravity. Now, NASA’s future human space exploration sets its sights on going back to the Moon, then onto Mars, aiming to establish a long-term human presence in the Solar System. Additionally, NASA’s science missions encompass Astrophysics, Earth Science, Heliophysics, Planetary Science, and Biological and Physical Sciences, yielding groundbreaking discoveries about our Sun, climate change, the Solar System and the Universe beyond and how life survives in the harshness of space. NASA’s extraordinary odyssey has left an indelible mark on human history, unlocking the secrets of the cosmos and igniting the dreams for past and future generations to come.

Submicroscopic magnetite may be ubiquitous in the lunar regolith of the high-Ti region

Magnetite is rare on the Moon. The ubiquitous presence of magnetite in lunar soil has been hypothesized in previous Apollo Mössbauer spectroscopy and electron spin resonance studies, but there is currently no mineralogical evidence to prove it. Here, we report a large number of submicroscopic magnetite particles embedded within iron-sulfide on the surface of Chang’e-5 glass, with a close positive correlation between magnetite content and the TiO 2 content of the surrounding glass. The morphology and mineralogy of the iron-sulfide grains suggest that these magnetite particles formed via an impact process between iron-sulfide droplets and silicate glass melt, and ilmenite is necessary for magnetite formation. Magnetite in lunar glass is a potential candidate for the “magnetite-like” phase detected in the Apollo era and suggests that impact-induced submicroscopic magnetite may be ubiquitous in high-Ti regions of the Moon. Moreover, these impact-induced magnetite particles may be crucial for understanding the lunar magnetic anomalies and mineral components of the deep Moon.

Lunar simulant behaviour variability and implications on terrestrial based lunar testing

The detrimental effects and challenges of Lunar dust for Lunar exploitation were first identified during the Apollo missions. During the extra vehicle activities (EVAs) undertaken by astronauts, the dust clogged mechanisms, disrupted sensors, and caused several health issues for the astronauts. Despite numerous studies, there is no definite understanding as to why different Apollo missions experienced varying levels of dust disruptions. The variations in dust behaviour could be attributed to the amount of radiation the Lunar soil is exposed to, as well as mineralogy and particle sizes. To enhance our understanding of Lunar dust behaviour this study investigated Space Recourse Technologies, formally known as Exolith, simulant at different mineral compositions, and their surface detachment characteristics were measured. Experiments measuring the individual minerals and their mixed simulant-like counterparts were conducted using electrostatic fields. Inclusive to this, non-dried and dried samples were compared by measuring adhesion to target plates when subject to electrostatic forces. The results found that Highlands simulant exhibited a higher buildup on a target plate than its Mare counterpart by an average of 33% under the same conditions, likely due to particle size differences. In addition to these findings, evidence of particle reactivity decay was observed under repeated tests with up to 60% less Mare simulant and 36% Highlands deposition being measured compared to the first set of experiments. A possible explanation may be particle reactivity. Microscope images identified that particles are transported in groups as opposed to individual grains. These results will help researchers in tailoring dust mitigation solutions based on different regions on the Lunar surface and influence mission planning from the perspective of dust mitigation and contamination.

Lunar soil record of atmosphere loss over eons.

The Moon has a tenuous atmosphere produced by space weathering. The short-lived nature of the atoms surrounding the Moon necessitates continuous replenishment from lunar regolith through mechanisms such as micrometeorite impacts, ion sputtering, and photon-stimulated desorption. Despite advances, previous remote sensing and space mission data have not conclusively disentangled the contributions of these processes. Using high-precision potassium (K) and rubidium (Rb) isotopic analyses of lunar soils from the Apollo missions, our study sheds light on the lunar surface-atmosphere evolution over billions of years. The observed correlation between K and Rb isotopic ratios (δ 87Rb = 0.17 δ 41K) indicates that, over long timescales, micrometeorite impact vaporization is the primary source of atoms in the lunar atmosphere.

Dataset of replicate Apollo sample magnetizations bearing on impacts and absence of a long-lived lunar dynamo

The absence or presence of a lunar paleomagnetosphere is important because it bears directly on the volatile content of the regolith and exploration targets for Artemis and other missions to the Moon. Recent paleointensity study of samples from the Apollo missions has readdressed this question. Multiple specimens from a young 2-million-year-old glass shows a strong magnetization compatible with that induced by charge-separation in an impact plasma, whereas paleointensities of single crystals yield evidence for null magnetizations spanning 3.9 to 3.2 Ga. Together, these data are consistent with an impact mechanism for the magnetization of some lunar samples, and absence of a long-lived lunar core dynamo and paleomagnetosphere recorded in other samples. Here, we present a dataset that allows researchers to examine replicates of these measurements. For the glass, we present data from specimens that fail standard paleointensity selection criteria but nevertheless imply a complex, changing magnetic field environment. For the single crystals, the replicate measurements further illustrate the initial zero magnetization state of these materials.

Slopes along Apollo EVAs: Astronaut experience as input for future mission planning

One major factor for operational safety and planning of human extravehicular activities (EVAs) is the topography of the landing region. During planning for EVAs for future crewed missions, digital elevation models (DEMs) and derived slope maps are often used to place constraints on proposed EVA paths to minimize the slopes and vertical meters traveled. However, the specification of these constraints has not yet been studied in detail and has to date relied on generalized assumptions. The Apollo program was the subject of meticulous planning and execution over an extended period. Our study concentrated on the pivotal aspect of mission planning, namely the topographic conditions of all Apollo landing sites. Furthermore, there are numerous conditions of lunar exploration whose "ground truth" can only be fully comprehended by astronauts who have personally visited the Moon. Certainly, there are technical constraints for the use and operation of equipment and tools, such as suits and instrument carts. However, astronaut observational physiological and psychological experiences and constraints are need to be considered for the planning of successful EVAs. In this study, we examined a variety of data sources, including topographic data, Apollo astronaut reports, audio and video recordings, in order to assess their experience and performance in relation to the topography and slopes along each Apollo extra vehicular activity (EVA). The ability of the astronauts to accurately perceive distances, slopes, and to move with confidence is contingent upon topographic and illumination conditions, as well as the specific equipment that they are required to carry. Future mission planning must take realistic traverse speeds into account, as well as the perception of both real and perceived hazards on challenging traverses.

Sensing technologies for the challenging Lunar environment

This study reviews major sensing technologies for the Lunar environment and its resources, as they have been developed since the times of Apollo missions. Selected technologies of sensors and instruments for the chemical, isotopic, and structural analysis of Lunar rocks and regoliths, as well as of the Lunar exosphere environment, are presented in a critical review towards an optimised and information-rich framework. Special focus is given on the activated Lunar regolith, and especially the Lunar dust, describing the development of Lunar simulants as the only accessible materials for experimentation and testing of the above technologies. New technologies are also highlighted, such as the development of the OxR microfluidic and spectroscopy integrated device, which, in its small scale aims to detect reactive oxygen species in the Lunar regolith, while in its larger format it is used to release oxygen gas from the Lunar dust and regolith, enabling astronaut respiration and fuel production on the Moon. It is finally suggested that miniaturisation of instruments and sensors, together with the standardisation of output information and characterisation protocols through holistic informational frameworks, will enhance the dynamic expansion and further integration and interoperation of sensors and devices, aiming to an efficient, safer, and resilient utilisation on the Moon and the establishment of sustainable settlements in the near future.

Lunar Lithium-7 Sensing (δ7Li): Spectral Patterns and Artificial Intelligence Techniques.

Lithium, a critical natural resource integral to modern technology, has influenced diverse industries since its discovery in the 1950s. Of particular interest is lithium-7, the most prevalent lithium isotope on Earth, playing a vital role in applications such as batteries, metal alloys, medicine, and nuclear research. However, its extraction presents significant environmental and logistical challenges. This article explores the potential for lithium exploration on the Moon, driven by its value as a resource and the prospect of cost reduction due to the Moon's lower gravity, which holds promise for future space exploration endeavors. Additionally, the presence of lithium in the solar wind and its implications for material transport across celestial bodies are subjects of intrigue. Drawing from a limited dataset collected during the Apollo missions (Apollo 12, 15, 16, and 17) and leveraging artificial intelligence techniques and sample expansion through bootstrapping, this study develops predictive models for lithium-7 concentration based on spectral patterns. The study areas encompass the Aitken crater, Hadley Rima, and the Taurus-Littrow Valley, where higher lithium concentrations are observed in basaltic lunar regions. This research bridges lunar geology and the formation of the solar system, providing valuable insights into celestial resources and enhancing our understanding of space. The data used in this study were obtained from the imaging sensors (infrared, visible, and ultraviolet) of the Clementine satellite, which significantly contributed to the success of our research. Furthermore, the study addresses various aspects related to statistical analysis, sample quality validation, resampling, and bootstrapping. Supervised machine learning model training and validation, as well as data import and export, were explored. The analysis of data generated by the Clementine probe in the near-infrared (NIR) and ultraviolet-visible (UVVIS) spectra revealed evidence of the presence of lithium-7 (Li-7) on the lunar surface. The distribution of Li-7 on the lunar surface is non-uniform, with varying concentrations in different regions of the Moon identified, supporting the initial hypothesis associating surface Li-7 concentration with exposure to solar wind. While a direct numerical relationship between lunar topography and Li-7 concentration has not been established due to morphological diversity and methodological limitations, preliminary results suggest significant economic and technological potential in lunar lithium exploration and extraction.

Predicting Deep Moonquake Source Regions Using Their Temporal and Spatial Patterns and Machine Learning

AbstractIn the near future, lunar exploration should be enhanced by deploying a new seismic station on the farside of the Moon, the Farside Seismic Suite (FSS), a package of two seismometers recently selected by NASA to fly on a commercial lander. The new data should provide us with new insights into Moon's seismic activity, its interior, and composition. To fully benefit from the new data, we need to take advantage of the data acquired during the Apollo missions. The problem of relating new and old data is complex due to the single‐station nature of the future deployment. In this study, we tackle this issue by developing a machine learning model in the context of the deep moonquake (DMQ) classification problem. The DMQs form the largest group of detected events from Apollo data, and their source regions have been located and are known to exhibit temporal and spatial patterns connected with the monthly lunar tidal periods. Therefore, we propose to utilize a machine learning (ML) algorithm named random forest to identify DMQs source regions without using waveform information and only using the lunar orbital parameters related to DMQs time occurrences. We show that ML models perform well (with an accuracy &gt;70%) when they are trained to classify 4 or fewer different source regions. This approach gives us a good first location approximation of the DMQs source regions and opens up a new approach to their location estimate when captured by the future FSS single‐station seismometers.

The Selene Mission: Paving the Way for a Large-Scale Commercial Moon Colony and a Multi-Trillion-Dollar Lunar Economy

The Selene Mission, spearheaded by Titans Space Industries, endeavors to establish a large-scale commercial settlement on the Moon, Titania Lunar, ushering in a new era of lunar exploration and economic activity. Building upon NASA's Apollo and Artemis missions, Selene aims to achieve this ambitious goal earlier and more cost-effectively, supported by substantial funding from Titans Astronauts. This initiative envisions transforming the Moon into a vibrant frontier for human habitation and commerce. Drawing inspiration from NASA's Artemis program, Project Selene seeks to create a sustainable space transport system for cis-lunar travel, laying the groundwork for a thriving lunar economy. The mission comprises three phases: establishing a robust lunar transportation network, developing Titania Lunar into a flourishing base, and evolving it into a bustling metropolis. Key components of the mission include reusable spacecraft, orbital staging posts, a lunar surface transportation network, pressurized habitats, in-situ resource utilization, and lunar power generation. Collaborative efforts with private partners and international entities will drive innovation and investment, while responsible tourism and resource extraction will fuel economic growth. The Selene Mission not only promises economic potential, with projections of a multi-trillion-dollar lunar economy, but also scientific advancements and societal benefits. By inspiring future generations and fostering global unity, this mission marks a paradigm shift in humanity's relationship with the Moon. Ultimately, the Selene Mission heralds a future where humans thrive on the Moon, creating a sustainable and prosperous lunar civilization.

Like a Phoenix from the Ashes: Management Control and Organizational Resilience During NASA's Apollo and Space Shuttle Programs

This study draws on archival sources to investigate the ways in which management control may contribute to and support organizational resilience by analyzing crises from the National Aeronautics and Space Administration's (NASA) Apollo (1961–1972) and Space Shuttle (1972–2011) programs. Both programs suffered significant events with tragic consequences. A fire killed three astronauts during a launch rehearsal test of Apollo 1. During the Space Shuttle program, the Challenger broke apart shortly after launch, and the Columbia disintegrated upon re‐entering Earth's atmosphere; both tragedies resulted in the death of all seven crew members. NASA's recovery from the three disasters and subsequent achievements exemplifies organizational resilience. This study analyzes and discusses how management control contributed to such efforts, which enabled the space programs to rise like a phoenix from the ashes of crises which could have very well led to the abandonment of the United States’ spacefaring endeavours.

Possibility of Lunar Crustal Magmatism Producing Strong Crustal Magnetism

AbstractThe Moon generated a long‐lived core dynamo magnetic field, with intensities at least episodically reaching ∼10–100 μT during the period prior to ∼3.56 Ga. While magnetic anomalies observed within impact basins are likely attributable to the presence of impactor‐added metal, other anomalies such as those associated with lunar swirls are not as conclusively linked to exogenic materials. This has led to the hypothesis that some anomalies may be related to magmatic features such as dikes, sills, and laccoliths. However, basalts returned from the Apollo missions are magnetized too weakly to produce the required magnetization intensities (&gt;0.5 A/m). Here, we test the hypothesis that subsolidus reduction of ilmenite within or adjacent to slowly cooled mafic intrusive bodies could locally enhance metallic FeNi contents within the lunar crust. We find that reduction within hypabyssal dikes with high‐Ti or low‐Ti mare basalt compositions can produce sufficient FeNi grains to carry the minimum &gt;0.5 A/m magnetization intensity inferred for swirls, especially if ambient fields are &gt;10 μT or if fine‐grained Fe‐Ni metals in the pseudo‐single domain grain size range are formed. Therefore, there exists a possibility that certain magnetic anomalies exhibiting various shapes such as linear, swarms, and elliptical patterns may be magmatic in origin. Our study highlights that the domain state of the magnetic carriers is an under‐appreciated factor in controlling a rock's magnetization intensity. The results of this study will help guide interpretations of lunar crustal field data acquired by future rovers that will traverse lunar magnetic anomalies.