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

US space policy: still on hold?

Protecting Lunar Colonies From Space Radiation

The National Aeronautics and Space Administration’s (NASA) human space exploration programs are focused on leading safe, innovative, and sustainable efforts with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities. From space exploration programs in low-Earth orbit (LEO), such as the International Space Station (ISS), to lunar exploration programs, such as Artemis, the ultimate goal is to gain knowledge and develop the necessary technology required to explore and potentially inhabit other planets, such as Mars. For human exploration missions, crew safety is a priority. There is a multitude of health risks associated with the space environment, ranging from microgravity and radiation effects on the human body to long-term isolation impacts. When it comes to space radiation, both ionizing and non-ionizing radiation (NIR) exposures above pre-established limits can cause detrimental biological effects. The main NIR sources of interest for crew protection include lasers, natural and artificial incoherent light sources (e.g., sunlight, LEDs, lamps, etc.) and radiofrequency emitters (e.g., antennas, RFID, etc.). With the technology advancements over the last decades, stronger lasers and radio antennas are now available to use for routine operations (e.g., space communications, vehicle docking, etc.). The NASA Safety program at the Johnson Space Center (JSC) uses agency developed standards and risk specific developed requirements by the agency’s subject matter experts (SMEs) for all human space flight programs: International Space Station (ISS), Commercial Crew (CC), Orion Multi-Purpose Crew Vehicle (MPCV), Artemis, Gateway station, Human Landing System (HLS), Commercial LEO destinations (Axiom), Exploration Extravehicular Mobility unit (xEMU). The need for dedicated requirements for each of the human spaceflight risks is dictated by the unique challenges associated with space operations that often result in specific safety procedures and novel risk mitigation techniques. The requirements are developed in-house at the JSC by the discipline SMEs, approved by the NASA Health Medical Technical Authority (HMTA) office and concurred by the NASA Safety and NASA’s International Partners. Therefore, the safety process requires a proactive, flexible, and highly adaptive risk management approach for lasers and other NIR sourcesthat is unique to spaceflight compared tomore traditional terrestrialsafety processes. This presentation will provide an overview of the ionizing and non-ionizing radiation safety process for human spaceflight, with focus on laser safety. NASA requirements process, risk mitigation strategies and challenges for safe operational implementation will be discussed.

The Indian Space Research organization (ISRO) is currently embarking on an ambitious human spaceflight (HSF) program. The Indian government approved a budget of ₹10,000 Crores (~$1.4 Billion) in December 2018. The Indian HSF program is expected to give impetus to economic activities, employment generation in high-tech areas, human resources development and enhanced industrial capabilities. A robust and sustainable human spaceflight capability will enable India to participate as a collaborating partner in future global space exploration initiatives to Moon, Mars and beyond with long-term national benefits. The aim of ISRO’s first HSF mission, “Gaganyaan (Sky Craft)” is to accomplish the Indian HSF with the objective to carry a crew of three to Low Earth Orbit (LEO) and return them safely to a predefined destination on Earth. The program is proposed to be implemented in a single phase with two uncrewed missions (G1 & G2) followed by a crewed mission (H1). ISRO has identified several critical technologies needed for the Indian HSF Program: Crew Module (CM) System, Crew Escape System (CES), Environmental Control and Life Support System (ECLSS), Service Module (SM) System, and the Human Rated Launch Vehicle (HRLV) based on the GSLV Mk-III Rocket. The design of the Orbital Module (OM) consisting of the CM and SM has been completed along with the design of HRLV. The realization of the CES for qualification tests, TV-D1 Mission and G1 mission is underway with multiple industry vendor participation. Various ground segment activities for the Gaganyaan HSF program such as ground stations for end-to-end communication throughout the mission are also under development. This paper presents an applied Model-Based Systems Engineering (MBSE) perspective on the Indian HSF (IHSF) Program by first defining the MBSE approach, identifying the main system components, decomposition of system and subsystem elements for the Gaganyaan Mission based on the ISRO human spaceflight concept study and mission design documents. The stakeholder Domain package defines the Gaganyaan Mission elements, launch and ground systems, low earth orbit space environment, and constraints such as budgets, and technical capabilities. The space system modules and subsystem elements are explored through a federation of models approach utilizing the SysML based visualization diagrams on requirements, structure (package and block definition), and behaviors (use case and activity).

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.

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.

With the hindsight of more than 40 years of human space exploration experience, public support for space is essential to sustaining government funding for space endeavors. Poll after poll shows that the public is generally supportive of space exploration, but that support is passive and shallow. Although space is integrated into many facets of daily life, the general public’s knowledge of space activities is not commensurate with the benefits derived from them. The public’s concept of the cost of space endeavors or the extent of taxpayer investment in space is generally erroneous. Space agencies, the aerospace industry, and space-related entities need to communicate better the contributions of space to society and the excitement of space exploration and discovery.In March 2001, a Working Group of the American Institute for Aeronautics and Astronautics (AIAA) considered ways to promote public awareness of the benefits and excitement of space activities; its findings and recommendations are presented in this paper. Without significant improvements in public outreach coordination, the future of human spaceflight beyond the International Space Station (ISS) will be hard to sell to the legislators who must underwrite the major share of the initial costs of humanity’s sustained progression beyond low Earth orbit. The AIAA Working Group recognized that it will take time and effort to coordinate a long-term commitment to an international outreach and communication strategy. International discussions should begin without delay to enhance efforts to garner public support for human spaceflight activities aboard the ISS, and to map out a broad plan with national and international elements to educate the public and harness support for the potential of human spaceflight beyond the ISS.KeywordsSpace ActivitySpace ExplorationInternational Space StationSpace CommunityWorkforce DevelopmentThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

For the first time since the Apollo era, NASA is planning on sending astronauts on flights beyond LEO. The Human Space Flight (HSF) program started with a successful initial flight in Earth orbit, in December 2014. The program will continue with two Exploration Missions (EM): EM-1 will be unmanned and EM-2, carrying astronauts, will follow. NASA established a multi-center team to address the communications, and related tacking/navigation needs. This paper will focus on the lessons learned by the team designing the architecture and operations for the missions. Many of these Beyond Earth Orbit lessons had to be re-learned, as the HSF program has operated for many years in Earth orbit. Unlike the Apollo missions that were largely tracked by a dedicated ground network, the HSF planned missions will be tracked (at distances beyond GEO) by the DSN, a network that mostly serves robotic missions. There have been surprising challenges to the DSN as unique modern human spaceflight needs stretch the experience base beyond that of tracking robotic missions in deep space. Close interaction between the DSN and the HSF community to understand the unique needs (e.g. 2-way voice) resulted in a Concept of Operations (ConOps) that leverages both the deep space robotic and the Human LEO experiences. Several examples will be used to highlight the unique challenges the team faced in establishing the communications and tracking capabilities for HSF missions beyond Earth Orbit, including: Navigation. At LEO, HSF missions can rely on GPS devices for orbit determination. For Lunar-and-beyond HSF missions, techniques such as precision 2-way and 3-way Doppler and ranging, Delta-Difference-of-range, and eventually possibly on-board navigation will be used. At the same time, HSF presents a challenge to navigators, beyond those presented by robotic missions - navigating a dynamic/noisy spacecraft. Impact of latency - the delay associated with Round-Trip-Light-Time (RTLT). Imagine trying to have a 2-way discussion (audio or video) with an astronaut, with a 2-3 sec or more delay inserted (for lunar distances) or 20 minutes delay (for Mars distances). Balanced communications link. For robotic missions, there has been a heavy emphasis on higher downlink data rates, e.g. bringing back science data. Higher uplink data rates were of secondary importance, as uplink was used only to send commands (and occasionally small files) to the spacecraft. The ratio of downlink-to-uplink data rates was often 10:1 or more. For HSF, a continuous forward link is established and rates for uplink and downlink are more similar.

The future of space exploration will not be limited to sortie-style missions to single destinations. Even in present exploration taking place at the International Space Station in low-Earth orbit, logistics is complicated by flights arriving from five launch sites on Earth. The future challenges of space logistics given complex campaigns of interconnected missions in deep space will require innovative tools to aid planning and conceptual design. This paper presents a modeling framework to evaluate the propulsive and logistics feasibility of space exploration from the macro-logistics perspective, which covers the delivery of elements and resources to support demands generated during exploration. The modeling framework is implemented in a versatile and unifying software tool, SpaceNet, for general space exploration scenario analysis. Four space exploration scenarios are presented as application cases to highlight the applicability of the framework across vastly different scenarios. The first case investigates the resupply of the International Space Station between 2010 and 2015 using 77 missions combining NASA, European Space Agency, Japanese Space Agency, Russian Space Agency, and commercial space transportation. The second case models a lunar outpost build-up consisting of 17 flights to achieve continuous human presence over eight years. The third case models and evaluates a conceptual sortie-style mission to a nearEarth object, 1999 AO10. Finally, the fourth case models a flexible path type human exploration in the vicinity of Mars using a combination of human and tele-operated exploration. Taken together these cases demonstrate the challenges and logistical requirements of future human space exploration campaigns during the period from 20102050 and illustrate the ability of SpaceNet to model and simulate the feasibility of meeting these requirements.

In the wake of the Space Shuttle Columbia accident, NASA began to formulate post-shuttle human space exploration plans. A decade later, NASA is no closer to sending humans beyond low Earth orbit. During that time, NASA had adopted two major visions for the future of human space exploration: the 2004 Vision for Space Exploration, and the 2010 National Space Policy of the United States of America. Both of these visions led to studies intended to guide NASA’s path to far-reaching exploration destinations. However, the architectures developed in these studies failed to align with their corresponding visions. As a result of this rift and the steady budget decline over the past 20 years, NASA has neither met milestones outlined in the architecture, nor realized the visions that would return the United States to the forefront of human space exploration. This paper reviewed NASA’s space exploration plans beyond low Earth orbit, and identify the discontinuity between the exploration visions and the resulting architectures and programs. NASA’s current exploration planning process, from vision to program, has exhibited a cyclical pattern that hinders tangible progress to sending humans back beyond low Earth orbit. Additionally unrealistic fiscal assumption have contributed to inability to meet programmatic goals. For NASA to break the cycle and enable our astronauts to boldly go where no one has gone before, fundamental changes to the status quo are essential.

This paper presents an exploration strategy for human missions beyond Low Earth Orbit (LEO) and the Moon that combines the best features of human and robotic spaceflight. This Human Exploration using Real-time Robotic Operations (HERRO) strategy refrains from placing humans on the surfaces of the Moon and Mars in the near-term. Rather, it focuses on sending piloted spacecraft and crews into orbit around exploration targets of interest, such as Mars, and conducting astronaut exploration of the surfaces using telerobots and remotely controlled systems. By eliminating the significant communications delay with Earth due to the speed of light limit, teleoperation provides scientists real-time control of rovers and other sophisticated instruments, in effect giving them a virtual presence on planetary surfaces, and thus expanding the scientific return at these destinations. It also eliminates development of the numerous man-rated landers, ascent vehicles and surface systems that are required to land humans on planetary surfaces. The propulsive requirements to travel from LEO to many destinations with shallow gravity-wells in the inner solar system are quite similar. Thus, a single spacecraft design could perform a variety of missions, including orbit-based surface exploration of the Moon, Mars and Venus, and rendezvous with Near Earth Asteroids (NEAs), as well as Phobos and Deimos. Although HERRO bypasses many of the initial steps that have been historically associated with human space exploration, it opens the door to many new destinations that are candidates for future resource utilization and settlement. HERRO is a first step that takes humans to exciting destinations beyond LEO, while expanding the ability to conduct science within the inner solar system.

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.

Multidisciplinary evaluation of next steps for human space exploration: Technical and strategic analysis of options

A major goal for NASA's human spaceflight program is to send astronauts to near-Earth asteroids (NEA) in the coming decades. Missions to NEAs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of these primitive objects. However, before sending human explorers to NEAs, robotic investigations of these bodies would be required to maximize operational efficiency and reduce mission risk. These precursor missions to NEAs would fill crucial strategic knowledge gaps concerning their physical characteristics that are relevant for human exploration of these relatively unknown destinations. Dr. Paul Abell discussed some of the physical characteristics of NEOs that will be relevant for EVA considerations, reviewed the current data from previous NEA missions (e.g., Near-Earth Asteroid Rendezvous (NEAR) Shoemaker and Hayabusa), and discussed why future robotic and human missions to NEAs are important from space exploration and planetary defense perspectives.

A Delphi-Based Framework for systems architecting of in-orbit exploration infrastructure for human exploration beyond Low Earth Orbit