Will the US remain the real leader of human space exploration? A comparative assessment of space exploration policies

From outer space to Earth—The social significance of isolated and confined environment research in human space exploration

Science and human space exploration have historically developed as two entities independent from each other, where sometimes the interests of one community fight against those of the other, and where the achievements and budgets associated to human space exploration are seen as resources subtracted from science. However, science can benefit from human space exploration, and novel space missions designed on a global optimization, that balance both benefits for human space exploration and science, can constitute a new and financially sustainable approach for space exploration. The case for Near Earth Asteroids (NEAs) represents a good example, as associated to NEAs there is a mix of activities that includes both science (ground and space observations, robotic space missions, advanced remote sensing) and human space exploration (and operations), along with technology development and testing. The case of NASA's Asteroid Redirect Mission (ARM) will be analyzed, starting with a focus on its original goals and ambitions, what it achieved, how it has been perceived from the scientific community and the industrial complex, how it evolved, and how it ended, with a final consideration on its heritage and lessons learnt.

Becoming John Glenn in the Words of John Glenn

Human space exploration is frequently judged as being one of the boldest (technical) endeavours, on which humankind has embarked in its history. It is often described with very lofty terms, especially when looking for arguments, why humans engage in human space exploration in the first place. The desire and even the necessity to go beyond the known in order to be able to grow, the wish or even the imperative to expand life into the universe, are just two arguments, which are often brought forward when discussing human space exploration. From this and similar arguments one may conclude that the focus of space exploration is not only on the scientific discovery of today’s unknown worlds. It is not just about enhancing our knowledge and understanding of the universe — how it looks today, how it developed and which laws govern its evolution. One could argue that besides these scientific achievements the attempt of the human to leave Earth and to travel into space is a manifestation of the “undefined striving into the open” as the German theologian Wolfhart Pannenberg describes the seemingly untiring driving force, which motivates human action.239 Thus, human space exploration must not only be seen as an outward journey. It also needs to focus on the human being itself, as the human being appears to be at the centre of this activity. This raises the question of who the human being really is, which can be understood as a question regarding the identity of a human being.

A truly international lunar base as the next logical step for human spaceflight

During the summer of 2009, a flexible path scenario for human and robotic space exploration was developed that enables frequent, measured, and publicly notable human exploration of space beyond low-Earth orbit (LEO). The formulation of this scenario was in support of the Exploration Beyond LEO subcommittee of the Review of U.S. Human Space Flight Plans Committee that was commissioned by President Obama. Exploration mission sequences that allow humans to visit a wide number of inner solar system destinations were investigated. The scope of destinations included the Earth-Moon and Earth-Sun Lagrange points, near-Earth objects (NEOs), the Moon, and Mars and its moons. The missions examined assumed the use of Constellation Program elements along with existing launch vehicles and proposed augmentations. Additionally, robotic missions were envisioned as complements to human exploration through precursor missions, as crew emplaced scientific investigations, and as sample gathering assistants to the human crews. The focus of the flexible path approach was to gain ever-increasing operational experience through human exploration missions ranging from a few weeks to several years in duration, beginning in deep space beyond LEO and evolving to landings on the Moon and eventually Mars.

As an emerging interdiscipline, space life science, generated and developed with human space, especially manned space exploration,, covering very wide research fields. In the past more than half a century, many significant findings and achievements have been achieved in this field, which not only supports the missions of manned space exploration, but also provides service for the life on the earth. With the continuous development of Chinese manned space and deep space exploration activities, especially the startup of Chinese manned space station project, the next two decades will be the prime time for the development of Chinese space life science. To conduct space life science, obtain new knowledge and innovative technology and provide further service for human space exploration, national economic and social development basing on Chinese manned space station and return type scientific satellite experiment platform, which need us to study and thinking systematically from the strategic perspective of subject development. By reviewing the historical and current development of space life science at home and abroad, this essay analyzes and prospects the strategic needs, key scientific problems and development direction of Chinese space life science, in order to provide inspiration and reference for its development.

Human exploration of the Moon and Mars will require transportation of personnel and thousands of tons of cargo from Earth to the lunar and Martian surfaces. To accomplish this we wil l need several major new transportation systems, including a heavy lift launch vehicle to hurl large quantities of cargo into orbit around the Earth, and space transfer vehicles to ferry personnel and cargo from Earth orbit to their lunar and Martian destinations. This paper addresses a major question facing planners of these transportation systems: whether orbiting transportation nodes should play a role in this space transportation infrastructure of the future. After the last ApoUo mission to the Moon two decades ago, many space planners assumed that our next generation of lunar missions would be staged from an EaRh-orbiting station, using transfer vehicles which return to the station for reuse without having to be returned to the Earth's surface. However, the most recent NASA plans for lunar and Mars exploration more closely resemble the Apollo scenario in that they do not require transportation nodes, instead relying on expendable transfer vehicles which require a minimum of on-orbit assembly. This paper surveys the major functions that could be performed at a transpodon node, with emphasis on the vehicle support tasks an Earth-orbiting facility could play during early lunar and Mars missions: assembly, servicing, fueling, turnaround. and rescue. The rationale for performing these functions at a uansportation node is examined, and principal requirements for supporting these functions are addressed, including major technology development needs. A key conclusion of this assessment is that transportation nodes offer important long term benefits to human exploration, but that insufficient work is being conducted to develop the technologies required to support operations at such nodes. Development of such technologies should be afforded a higher priority, even if near term budgetary constraints force us to minimize the role of orbital operations during early space exploration missions.

This paper describes the results of a study into the feasibility of identifying, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the vicinity of the Earth by the middle of the next decade. The feasibility of such an asteroid retrieval mission hinges on finding an overlap between the smallest NEAs that could be reasonably discovered and characterized and the largest NEAs that could be captured and transported in a reasonable flight time. This overlap appears to be centered on NEAs roughly 7 m in diameter corresponding to masses in the range of 250,000 kg to 1,000,000 kg. The study concluded that it would be possible to return a ~500,000-kg NEA to high lunar orbit by around 2025. The feasibility is enabled by three key developments: the ability to discover and characterize an adequate number of sufficiently small nearEarth asteroids for capture and return; the ability to implement sufficiently powerful solar electric propulsion systems to enable transportation of the captured NEA; and the proposed human presence in cislunar space in the 2020s enabling exploration and exploitation of the returned NEA. Placing a 500-t asteroid in high lunar orbit would provide a unique, meaningful, and affordable destination for astronaut crews in the next decade. This disruptive capability would have a positive impact on a wide range of the nation’s human space exploration interests. It would provide a high-value target in cislunar space that would require a human presence to take full advantage of this new resource. It would offer an affordable path to providing operational experience with astronauts working around and with a NEA that could feed forward to much longer duration human missions to larger NEAs in deep space. It represents a new synergy between robotic and human missions in which robotic spacecraft would retrieve significant quantities of valuable resources for exploitation by astronaut crews to enable human exploration farther out into the solar system. The capture, transportation, examination, and dissection of an entire NEA would provide valuable information for planetary defense activities that may someday have to deflect a much larger near-Earth object. Transportation of the NEA to lunar orbit with a total flight time of 6 to 10 years would be enabled by a ~40-kW solar electric propulsion system with a specific impulse of 3,000 s. The flight system could be launched to low-Earth orbit (LEO) on a single Atlas V-class launch vehicle, and return to lunar orbit a NEA with at least 28 times the mass launched to LEO. Longer flight times, higher power SEP systems, or a target asteroid in a particularly favorable orbit could increase the mass amplification factor from 28-to-1 to 70-to-1 or greater. The NASA GRC COMPASS team estimated the full life-cycle cost of an asteroid capture and return mission at ~$2.6B.

US space policy: still on hold?

While debate continues on whether the Moon, Mars, or Near Earth Objects should be the first or focal destination for resending humans beyond Low Earth Orbit (LEO), all agree that the human space exploration needs to be sustainable and affordable, and that new and innovative technologies and infrastructure are required. One approach NASA is developing that can significantly change how systems required for space transportation and sustained human presence are designed and integrated, as well as potentially breaks our reliance on Earth supplied logistics and enable space commercialization is In-Situ Resource Utilization (ISRU). ISRU, or “living off the land”, involves the identification, extraction, and processing of resources at the site of exploration into useful products and services. In particular, the ability to make propellants, life support consumables, fuel cell reagents, and radiation shielding can significantly reduce the cost, mass, and risk of sustained human activities beyond LEO. Also, the ability to modify planetary surface material for safer landings, lower maintenance of surface transportation, dust generation mitigation, and infrastructure protection, placement, and buildup are also extremely important for long-term planetary surface operations. At first glance, it appears that the resources available and the environmental conditions on the Moon and Mars are different enough that close synergism between lunar and Mars ISRU technologies and systems and how they are incorporated into mission scenarios is not possible. However, upon closer examination, it can be shown that there are significant synergisms in ISRU technologies, systems, and operations between the Moon and Mars. Incorporating ISRU capabilities into lunar missions and using the Moon as a test platform for future Mars missions may also significantly reduce the cost, mass, and risk for both human exploration destinations while providing a logical stepping stone approach to achieving sustainable and affordable human exploration. This paper will outline past and current technology and system development efforts by NASA for lunar and Mars ISRU, and how using the precursor missions to the Moon and Mars can reduce the cost and risk associated with human lunar and Mars exploration.

The present thesis describes the PhD research activities dealing with the topic Exploration Systems, Strategies and Solutions. Traveling beyond low Earth orbit is the next step in the conquest of the solar system and so far, a human expedition to Mars is considered the most interesting goal of future human space exploration. Due to the technological and operational challenges associated with such a mission, it is necessary to define an opportune path of exploration, relying on many missions to intermediate and easier destinations, which would allow a gradual achievement of the capabilities required for the human Mars mission. The main scope of this research has been the development of a rigorous and versatile methodology to define and analyze evolutionary exploration scenarios and to provide a detailed technologies' database, to support strategic decisions for human space exploration. The very innovative aspect of this work regards the development of a flexible methodology which can be followed to assess which are the next destinations for the exploration of space beyond LEO and to preliminarily define mission's architectures, identifying the most significant needed elements and advanced technologies. The obtained results should be seen as a pure technical reference, as no cost and/or political considerations have been included, and can be exploited to opportunely drive the decisions of the agencies to place investments for the development of specific technologies and get ready for future exploration missions. The first part of the work has been devoted to the definition of a reference human space exploration scenario, which relies on both robotic and human missions towards several destinations, pursuing an increasing complexity approach and looking at a human expedition to Mars as final target. The scenario has been characterized through the assessment of the missions and the relative phases and concepts of operations. Accordingly, the needed space elements, or building blocks, have been identified. In this frame, the concept design of two specific elements has been performed: the first is a pressurized habitation module (Deep Space Habitat) for hosting astronauts during deep space missions; the second is an electrical propulsive module (Space Tug), mainly envisioned for satellites servicing. The last part of the work has focused on the analysis of innovative and enabling technologies, with particular attention to the aspects related to their on-orbit demonstration/validation, prior to their actual implementation in real exploration missions. The PhD has been sponsored by Thales Alenia Space - Italy and the overall work has been performed in different frameworks along the three years, as well as participating to several additional activities. In line with the objectives of the PhD, in 2012 a collaboration between Politecnico di and Massachusetts Institute of Technology has been established (MITOR Project, managed by MIT-Italy Program), with the support of Thales Alenia Space as industrial partner. The MITOR project, titled Space Exploration: from Scenario to Technologies, has been aimed at identifying and investigating state of the art for Human Space Ex- ploration, enabling elements, subsystems and technologies with reference to a selected scenario and relevant missions and architectures. Part of the nine months activities has been carried out at MIT AeroAstro department. Besides MITOR project, the PhD activities have been carried out in synergy with some other research programs, such as ESA Spaceflight & Exploration Scenario Studies and STEPS2 project (Sistemi e Tecnologie per l'EsPlorazione Spaziale - phase 2). Furthermore, in 2013 a specific study has been performed in collabora- tion with university La Sapienza (Rome), Osservatorio Astrofisico di Torino (Astrophysical Observatory of Torino) and DLR (Deutsches Zentrum fr Luft- und Raumfahrt) in Bremen; its main objective has been the analysis of an interplanetary cubesats mission, aimed at space weather evaluations and technologies demonstration

Goal-based operations, a form of operations that involves specifying what should be accomplished, as opposed to how operations are carried out, has the potential to significantly enhance human space exploration in a number of areas in both ground and space operations. Realizing this potential will require addressing several challenges, ranging from practical feasibility to operational reliability and user acceptance. We intend to provide a customer perspective and help address some of the challenges by: (1) highlighting general and specific challenges and opportunities that are consistent with human space exploration and that emphasize how goal-based operations might be of practical benefit to the human space exploration program; and (2) exploring ways to help increase confidence in goal-based operations. A strategy for building such confidence must consider: (a) incremental implementation of goal-based operations for increasingly ambitious operations leading eventually to high level goal-based operations, (b) the role of systems modeling in technology acceptance and infusion and (c) automation assessment tools for understanding how trust is developed, such as the Function-specific Level of Autonomy and Automation Tool (FLOAAT) developed by NASA/Johnson Space Center. We explore several challenges and opportunities for the near-term (International Space Station mission operations), the midterm (human lunar missions), and the long-term (human Mars missions), that illustrate the potential benefits of goal-based operations.

The negative effects of ionizing radiation on healthy tissue pose a medical challenge for both human space exploration as well as terrestrial medicine. Therefore, understanding the effectiveness of current treatments is important both in the application of current medicine and the development of new therapeutics. Health supplements are used widely in or by consumers to prevent the occurrence of symptoms following radiotherapy. To evaluate the possible efficacy of health supplements and their potential for use during deep space exploration, a systematic literature review was conducted. A search of PubMed, Cochrane Library and OVID (Medline) databases was conducted, identifying 77 studies that examined therapeutic effects of health supplements on ionizing radiation, of which 15 were eligible for inclusion in the analysis. Health supplements provided no beneficial effects to either functional or biochemical physiological outcomes. However, symptomatic relief was found in a range of irradiated areas of the body from a variety of health supplements following irradiation. The localized actions of both the radiotherapy and the health supplement means further investigations would be required before using these health supplements to protect against whole-body radiation exposure. Further investigations should also focus on the health supplements shown to have the greatest positive effects to address the lack of clinical consensus. The negative effects of ionizing radiation on healthy tissue pose a medical challenge for both human space exploration as well as terrestrial medicine. Therefore, understanding the effectiveness of current treatments is important both in the application of current medicine and the development of new therapeutics. Health supplements are used widely in or by consumers to prevent the occurrence of symptoms following radiotherapy. To evaluate the possible efficacy of health supplements and their potential for use during deep space exploration, a systematic literature review was conducted. A search of PubMed, Cochrane Library and OVID (Medline) databases was conducted, identifying 77 studies that examined therapeutic effects of health supplements on ionizing radiation, of which 15 were eligible for inclusion in the analysis. Health supplements provided no beneficial effects to either functional or biochemical physiological outcomes. However, symptomatic relief was found in a range of irradiated areas of the body from a variety of health supplements following irradiation. The localized actions of both the radiotherapy and the health supplement means further investigations would be required before using these health supplements to protect against wholebody radiation exposure. Further investigations should also focus on the health supplements shown to have the greatest positive effects to address the lack of clinical consensus. Keywords : Spaceflight; Astronauts; Environmental physiology; Healthcare; RadiotherapyKeywords: Spaceflight; Astronauts; Environmental physiology; Healthcare; Radiotherapy

The EXPLORE and STEMMOS  two complementary Erasmus + projects aim to transform space science education across Europe by integrating hands-on experiences, digital tools, and interdisciplinary learning approaches.The EXPLORE Project, led by the Austrian Space Forum (OeWF), engages students and educators in planetary science and human space exploration through innovative toolkits, real-world simulations, and training sessions. Implemented in collaboration with  EA, NUCLIO, COSPAR and  Biosky, the project provides participants with practical experience in mission planning and execution.Central to EXPLORE are two Student Analog Missions, scheduled for June 2025 and spring 2026 in Alqueva, Portugal. These missions simulate human Mars expeditions, immersing students in roles as analog astronauts and mission support personnel. Participants will carry out scientific experiments, habitat operations, and extravehicular activities, gaining the essential 21st-century skills of problem-solving, teamwork, and decision-making under simulated extraterrestrial conditions.A core component of the project is the development of physical and virtual toolkits to support experiential learning. Physical toolkits include sensors, data collection devices, and planetary surface models. Virtual toolkits provide mission planning software, interactive simulations, and digital learning resources, making planetary exploration accessible to diverse educational levels.EXPLORE offers training sessions for teachers, students, and schools to ensure the effective implementation of the toolkits. These sessions improve digital and scientific literacy, enabling participants to engage in space exploration activities. In addition, the project will provide in July 2025 a summer school for teachers, offering professional development on integrating space science into classroom practices.Meanwhile, the STEMMOS Project focuses on enhancing digital and STEAM competencies through Earth, Moon, and Mars Observation (EMMO) science. Led by Munster Technological University’s Blackrock Castle Observatory (Ireland), the project brings together five partners: NUCLIO, EA, Stem Education LTD (Bulgaria), NOA, and OeWF. STEMMOS aims to inspire students and educators by integrating digital tools, robotics, satellite data and innovative teaching methodologies.Key STEMMOS activities include national training sessions, a summer school, and experiential space science festivals in Ireland and Greece. Over 500 educators and 1,000 students will be directly engaged, with a focus on promoting gender inclusivity and diversity in STEAM education. The project features a Massive Open Online Course and a dedicated STEMMOS Hub, providing educators with freely accessible resources for interactive learning.Both projects emphasize interdisciplinary collaboration, bridging education and space exploration. While EXPLORE immerses students in realistic Mars mission scenarios, STEMMOS focuses on teaching EMMO science through digital tools and hands-on learning;  both provide comprehensive training for educators.Together, these initiatives create a lasting educational impact by connecting participants with cutting-edge space science, fostering sustainable teaching methodologies, and preparing future generations to address global challenges through careers in science, technology, and exploration.By advancing analog mission research, promoting space science education, and creating engaging learning environments, EXPLORE and STEMMOS contribute to Europe’s educational landscape. Both projects serve as platforms for building digital competencies, encouraging diversity, and equipping students with the skills to explore the next frontiers of satellite data and human space exploration.