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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRSDate not supplied

A Common Habitat Deep Space Exploration Vehicle for Transit and Orbital Operations

When outfitted as a habitat, the SLS Core Stage Liquid Oxygen Tank is a pressure vessel that can be used to support human exploration in deep space. An exploration spacecraft can be constructed with this habitat, known as the Common Habitat, as its central element. More than just a transit vehicle, this spacecraft is a Deep Space Exploration Vehicle – a microgravity science laboratory capable of conducting research with onboard human crews throughout the inner solar system. Supplied with propellant by LEO depots, preliminary trajectory and v estimates indicate that the spacecraft can perform fly-by or orbital missions with trajectories close enough to the sun to intersect the orbit of Mercury or far enough away to fly by the main belt asteroid Vesta. Its primary mission, however, is to support human expeditions to Mars. Many, though not all, of the pressurized and unpressurized elements that compose the Deep Space Exploration Vehicle can also be used in surface base camps on the Moon and Mars. In additional to traditional space science disciplines, the spacecraft offers unique potential for small asteroid retrieval and for artificial gravity research. Three launches are used to deploy the spacecraft, but thirty-nine launches are used to deliver propellant to orbit to fully fuel the spacecraft for deep space missions. Key operations in a Mars crewed mission are described to illustrate how the vehicle is used and forward work is listed to mature the spacecraft concept.

Robert L. Howard Jr.↗
NASA NTRS2004

Deep Space Ka-band Link Management and the MRO Demonstration: Long-term Weather Statistics Versus Forecasting

During the last 40 years, deep space radio communication systems have experienced a move toward shorter wavelengths. In the 1960s a transition from L- to S-band occurred which was followed by a transition from S- to X-band in the 1970s. Both these transitions provided deep space links with wider bandwidths and improved radio metrics capability. Now, in the 2000s, a new change is taking place, namely a move to the Ka-band region of the radio frequency spectrum. Ka-band will soon replace X-band as the frequency of choice for deep space communications providing ample spectrum for the high data rate requirements of future missions. The low-noise receivers of deep space networks have a great need for link management techniques that can mitigate weather effects. In this paper, three approaches for managing Ka-band Earth-space links are investigated. The first approach uses aggregate annual statistics, the second one uses monthly statistics, and the third is based on the short-term forecasting of the local weather. An example of weather forecasting for Ka-band link performance prediction is presented. Furthermore, spacecraft commanding schemes suitable for Ka-band link management are investigated. Theses schemes will be demonstrated using NASA's Mars Reconnaissance Orbiter (MRO) spacecraft in the 2007 to 2008 time period, and the demonstration findings will be reported in a future publication.

Mars Reconnaissance Orbiter (MRO)↗
NASA NTRS2022

NASA Utilization of Space Nuclear Systems for Robotic and Human Exploration Missions: Response to EO 13972: Promoting Small Nuclear Reactors for National Defense and Space Exploration

Space Nuclear Systems (SNS) technology development offers a wide range of capabilities to support NASA’s current and future missions. Executive Order (EO) 13972, “Promoting Small Modular Reactors for National Defense and Space Exploration” [1], issued 5 January 2021, directs NASA to define requirements for NASA utilization of nuclear energy systems for human and robotic exploration missions through 2040 and analyze the costs and benefits of such requirements.” Although it is premature to define requirements and cost for future exploration missions that have not yet been formulated, this report describes planned objectives and missions by 2040 that are enabled or enhanced by nuclear systems while taking into account a number of unique considerations for nuclear energy in the space environment. Nuclear energy systems are enabling for space missions and critical capabilities where conventional forms of energy production are impractical or impossible due to mass constraints, mission duration, or distance from the Sun. Space nuclear technologies available or in development for use by 2040 utilize radioisotope decay or nuclear fission and fall into three categories: heat, power, and propulsion. Current applications utilize radioisotope power systems that provide consistent and reliable performance in the sub-kilowatt power range. More advanced SNS can enable new mission objectives where high energy density solutions are critical, or where access to solar solutions is prohibitive. Higher power radioisotope and fission systems are under development within NASA for a wide variety of human exploration and science mission applications. Planned missions designed to use radioisotope systems include Dragonfly, a rotorcraft that will explore the surface of Titan, and Persephone, a mission concept for a Pluto orbiter. Nuclear fission systems have the key advantage of providing significantly higher power, lower mass solutions from tens to even thousands of kilowatts. Fission power is enabling to a sustained human presence on the Moon and developing a robust lunar economy. Fission propulsion is enabling for missions within and beyond cis-lunar space. This report examines NASA-envisioned mission applications and associated performance needs for SNS over the next twenty years leading to 2040 along with the unique technical considerations posed by space nuclear technology development. This includes engineering and operational logistics for ground handling, thermal management, survival of the space environment, operational safety, power requirements, and service longevity. Safety to the public, the NASA work force, and agency assets remains a top priority for NASA and particular attention is given to this aspect in the design, hardware assembly, ground operation, launch, and mission operation of an SNS. NASA relies on the Department of Energy as nuclear authority and its legacy of rigorous safety procedures as standards for ground development, test, transportation, and launch site operation. The principal concern is preventing unintended radiological release to the public or environment. Radioisotope system experience has established processes, including ground operation, transportation, and launch, that are considered directly applicable to emerging fission systems; however, fission systems have unique design needs that impact the safety and performance requirements. High efficiency power conversion from both fission and radioisotope systems requires high operating temperatures necessitating both passive and active thermal management to maintain safe and nominal operating conditions. Effective cooling and waste heat rejection have special considerations for space applications, whether in zero-g or reduced gravity. Fluid and heat transfer within the reactor system is not anticipated to be impacted by reduced or zero-g environments. Cryogenic working fluids and propellant supplies utilized in some space nuclear applications will need low mass, high capacity cryocoolers to meet the long-term storage and near zero-boiloff needs. Integrated, high power density SNS capable of being packaged in a single vehicle is a key consideration for NASA. Due to concerns for complexity and reliability, in space reactor assembly and reactor refueling are not current design considerations. Expanding into a new era for space exploration depends on mass-efficient, high-energy solutions to power deep-space vehicles, operate in harsh environments, and increase mission flexibility. NASA nuclear technology investments are targeting power for surface operations and propulsion for fast-transit, deep-space missions, all with the ability to reliably operate without the need for repair or refueling. NASA’s goals, enabled by nuclear technologies, provide for exciting advances in scientific objectives and human exploration, ushering in a new space age that enables a human presence on bodies beyond our Earth.

nuclear↗
NASA NTRS2019

Implementation of Human System Integration Workshop at NASA for Human Spaceflight

The human is a key element in the complex system of systems underlying space exploration missions. As a critical system, its operating bands and requirements need to be characterized and integrated with other systems. Optimal integration of the human system with hardware and software elements has an impact on multiple aspects of mission execution, including human health and performance, risk mitigation, effective design and functionality, enhanced safety, and reduced lifecycle costs. The field of Human Systems Integration (HSI) represents an interdisciplinary and comprehensive cross-cutting approach encompassing technical and management processes for integrating human as a system consideration and objective within and across all other system components and multiple domains. In addition to human activities, HSI covers training, operations and support dimensions. Moreover, HSI is an essential enabler to systems engineering practice, emphasizing human system aspects toward optimizing fully integrated system of systems performance while systematically infusing the needs of all users during the earliest stages of development. Consistent with the National Space Exploration Campaign, NASA is developing the Gateway, a lunar orbiting platform that will serve as astronaut habitat, support transit to deep space, validate new technologies and systems, and function as a science laboratory and communications hub, among other uses. It is an essential element of a phase that will extend human exploration into deep space through evolvable infrastructure and advanced technology, supporting assembly and logistics of other exploration architecture elements. In an effort to explore the current status and forward plan of HSI implementation in the mission (system of systems) lifecycle, the HSI Employee Resource Group conducted an HSI workshop using the Gateway Program as a case study. It revealed how different organizations at the Johnson Space Center incorporate HSI in their processes in preparation for the development and operation of the Gateway. The workshop focused on HSI methodology for implementation of the six NASA HSI domains: Human Factors Engineering, Operations Resources, Habitability and Environment, Maintainability and Supportability, Safety, and Training. Results from the workshop are reported on this paper, as well as some historical background of HSI at NASA, and the success in using an Employee Resource Group to promote technical knowledge. The authors hope that this information can be used to disseminate best practices for translational applications to other space exploration systems.

Silva-Martinez, Jackelynne↗
NASA NTRS2019

Implementation of Human System Integration Workshop at NASA for Human Spaceflight

The human is a key element in the complex system of systems underlying space exploration missions. As a critical system, its operating bands and requirements need to be characterized and integrated with other systems. Optimal integration of the human system with hardware and software elements has an impact on multiple aspects of mission execution, including human health and performance, risk mitigation, effective design and functionality, enhanced safety, and reduced lifecycle costs. The field of Human Systems Integration (HSI) represents an interdisciplinary and comprehensive cross-cutting approach encompassing technical and management processes for integrating human as a system consideration and objective within and across all other system components and multiple domains. In addition to human activities, HSI covers training, operations and support dimensions. Moreover, HSI is an essential enabler to systems engineering practice, emphasizing human system aspects toward optimizing fully integrated system of systems performance while systematically infusing the needs of all users during the earliest stages of development. Consistent with the National Space Exploration Campaign, NASA is developing the Gateway, a lunar orbiting platform that will serve as astronaut habitat, support transit to deep space, validate new technologies and systems, and function as a science laboratory and communications hub, among other uses. It is an essential element of a phase that will extend human exploration into deep space through evolvable infrastructure and advanced technology, supporting assembly and logistics of other exploration architecture elements. In an effort to explore the current status and forward plan of HSI implementation in the mission (system of systems) lifecycle, the HSI Employee Resource Group conducted an HSI workshop using the Gateway Program as a case study. It revealed how different organizations at the Johnson Space Center incorporate HSI in their processes in preparation for the development and operation of the Gateway. The workshop focused on HSI methodology for implementation of the six NASA HSI domains: Human Factors Engineering, Operations Resources, Habitability and Environment, Maintainability and Supportability, Safety, and Training. Results from the workshop are reported on this paper, as well as some historical background of HSI at NASA, and the success in using an Employee Resource Group to promote technical knowledge. The authors hope that this information can be used to disseminate best practices for translational applications to other space exploration systems.

Silva-Martinez, Jackelynne↗
NASA NTRSDate not supplied

Vertical Translation System for the Common Habitat Architecture

The Common Habitat is a large, long-duration habitat that uses an SLS core stage Liquid Oxygen (LOX) tank as its primary structure. Measuring 8.4 meters in diameter and 15 meters in length, it is manufactured as a habitat and launched as such into space. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. The Common Habitat Vertical Translation System provides a means for transporting crew and cargo between decks in a Common Habitat spacecraft in gravity levels varying from 0g to 1g. A crowdsourcing campaign was conducted through the GrabCAD platform to initially solicit ideas for restraints and mobility aids, including vertical translation. Four of the five top responses repeated ideas that would be incorporated into features of the Vertical Translation System. The first was a safety barrier (to prevent falls into the opening between decks) that could collapse to form a floor surface covering the opening when not in use. The second idea was a folding ladder that could be stowed in the ceiling when not in use. The third idea was an elevator platform that could traverse the ladder. Several key driving requirements were established for the Vertical Translation System: it may not penetrate into or through the lower deck; it must work on the Earth, Moon, Mars, and in microgravity; it must be easy to operate; it must enable translation of any item that can fit through the Common Habitat’s 40” x 60” hatches, inclusive of suited and unsuited crew with any degree of incapacitation and any equipment or cargo item; and it must include three component systems – deploying floor / safety barriers, a deployable ladder, and an elevator platform. Additional requirements were established for each of the component systems. The safety barriers must form a roughly 40-inch tall, complete wall enclosure on all four sides when deployed; it must include an easy to open gate that allows access to/from the ladder when deployed; and when retracted, the safety barrier must form a smooth, load-bearing floor that can be walked on, and wheeled objects can be rolled across in gravity, without being a trip hazard. The deployable ladder must be composed of multiple ladders that work together; it must stow in the ceiling when not in use; and it must not penetrate into the 40” x 60” vertical passage corridor. The elevator platform must work with the deployable ladder system; it must be able to bridge any gap in ladders between decks; it must stop at each deck flush with the deck surface; it must be capable of transporting an incapacitated crew member as a single rescuer operation; it must be capable of transporting a full-size subsystems pallet; it must function as an elevator for a crew member carrying large objects; it must have safety functions to prevent falls from the platform, or crew/cargo collisions with edges of hatch openings, or entanglement with ladder rungs/structure; it must stow when not in use; and it must autonomously both connect itself to the ladder and deploy itself to any deck where needed when called (e.g., a crew member on any deck can call for the platform and it must connect itself to the ladders without assistance and translate to the requestor’s deck). These requirements were developed into a system concept with the assistance of a NASA Pathways Intern who also added the requirement to size the design based on the use of commercial components, using existing motors and other mechanisms to ensure that the resulting system could be inexpensively produced. The Floor and Safety Barrier consists of four panels, two roughly 40 inches long and two roughly 60 inches long that can fold into the floor on top of each other when not in use. The uppermost panel is load bearing and acts as the floor surface. When deployed, they connect with each other to form a rigid barrier surrounding the vertical passageway. One of the panels contains a hinged gate that can be opened when deployed to allow for access to/from the passageway. The Deploying Ladder consists of two ladder segments, one mounted on the ceiling of the lower deck and the other mounted on the ceiling of the mid deck. A rotating mechanism is mounted on the ladder to allow it to rotate into a horizontal position against the ceiling for stowage, or down to a vertical position for use. A second rotating mechanism is built into the ladder, allowing the rungs to rotate. A toothed surface intended to work with the elevator platform covers the front of the ladder rails and the top and bottom of the rails are designed to be flush when aligned with another ladder segment. The elevator platform is essentially a motorized, self-propelled deck. It has a mechanism that holds it in contact with the ladder rails and drives itself against the toothed surface. This mechanism allows the elevator platform to ascend or descend the ladder. In order to stow the platform when not in use, a set of short ladder rails (without rungs) are mounted to the ceiling of the mid deck. When the mid deck ladder is stowed, it is flush with these rails and the platform can drive itself onto those short rails for stowage. An additional mechanism on the platform can pitch its deck surface 90 degrees, such that when the ladder is to be stowed, the platform can fold up against the ceiling. As a consequence of the ladder and elevator platform design, the opening between decks in the Common Habitat was enlarged to ensure that the elevator platform can accept a payload up to 40”x60” in dimension.

Human Centered Design↗
NASA NTRSDate not supplied

Functional Volume Assessment of an Early Version of the Mars Transit Habitat

During the summer of 2020, NASA assessed the transit habitat concept that was being used in Mars human exploration architecture studies. This assessment had six primary objectives: (1) provide a sanity check to the transit habitat concept layout; (2) understand if we can fit the hardware and functional tasks in the volume; (3) provide a high-level assessment of how aggressive the layout is; (4) generate a list of challenges or assumptions necessary to make it work; (5) generate a list of future work to refine understanding; and (6) identify proposed requirements. The results of this evaluation are discussed, including methodological challenges and rating challenges. Acceptability results are discussed for functions that the participants were able to rate and participant comments for functions that could not be evaluated are also described. Final conclusions are described, including challenges or assumptions needed to make the transit habitat concept design acceptable, future work needed to refine understanding of the transit habitat concept, and proposed habitat requirements based on test data. While NASA has since moved away from this architecture, the assessment is still useful to inform the design of future transit habitats or other deep space crewed vehicles.

Transit Habitat↗
NASA NTRSDate not supplied

Gateway Program Development Progress

This paper provides an overview and status of Gateway, humanity’s first space station to orbit the Moon providing vital support for a sustained, long-term human return to the lunar surface and a steppingstone to Mars as part of the Artemis missions. As a lunar outpost, Gateway is a destination for deep space crew expeditions and science investigations, a port for deep space transportation, including landers transiting to the lunar surface or spacecraft embarking to deep space destinations beyond the Earth-Moon system. The National Aeronautics and Space Administration (NASA) leads the Program and is the integrator of the spaceflight capabilities and contributions of U.S. commercial partners and international partners to develop Gateway. This paper will provide an overview of Gateway’s major components in various stages of development. The entire Gateway spacecraft is at preliminary design level of maturity, with some components at or near critical design review. Gateway’s major components are the Power and Propulsion Element; the Habitation and Logistics Outpost; Deep Space Logistics; the International Habitation module; Gateway External Robotics System; European System Providing Refueling, Infrastructure and Telecommunications; and an Airlock. This paper will also provide an update on the status of the integration activities necessary to fly and operate this complex, next-generation integrated spacecraft for a minimum 15 year design life, including systems engineering integrated analysis cycles, the autonomous Vehicle System Manager software, verification and validation labs, and common vehicle equipment. Expanding on the successful partnership that has provided over 20 years of continuous crew operations in low-Earth orbit on the International Space Station, Gateway is an evolution of this extraordinary partnership leveraging the capabilities of each contributor to expand humankind’s sustained exploration deeper into the cosmos. Highlighting the international program with participation from multiple space agencies, this paper will also provide a status of Gateway multilateral governance structure and international agreements.

Sean M Fuller↗
NASA NTRS2024

Gateway Program Development Progress

This paper provides an overview and status of Gateway, humanity’s first space station to orbit the Moon providing vital support for a sustained, long-term human return to the lunar surface and a steppingstone to Mars as part of the Artemis missions. As a lunar outpost, Gateway is a destination for deep space crew expeditions and science investigations, a port for deep space transportation, including landers transiting to the lunar surface or spacecraft embarking to deep space destinations beyond the Earth-Moon system. The National Aeronautics and Space Administration (NASA) leads the Program and is the integrator of the spaceflight capabilities and contributions of U.S. commercial partners and international partners to develop Gateway. This paper will provide an overview of Gateway’s major components in various stages of development. The entire Gateway spacecraft is at preliminary design level of maturity, with some components at or near critical design review. Gateway’s major components are the Power and Propulsion Element; the Habitation and Logistics Outpost; Deep Space Logistics; the International Habitation module; Gateway External Robotics System; European System Providing Refueling, Infrastructure and Telecommunications; and an Airlock. This paper will also provide an update on the status of the integration activities necessary to fly and operate this complex, next-generation integrated spacecraft for a minimum 15-year design life, including systems engineering integrated analysis cycles, the autonomous Vehicle System Manager software, verification and validation labs, and common vehicle equipment. Expanding on the successful partnership that has provided over 20 years of continuous crew operations in low-Earth orbit on the International Space Station, Gateway is an evolution of this extraordinary partnership leveraging the capabilities of each contributor to expand humankind’s sustained exploration deeper into the cosmos. Highlighting the international program with participation from multiple space agencies, this paper will also provide a status of Gateway multilateral governance structure and international agreements.

Gateway↗
NASA NTRS2011

Deep Space Habitat Concept of Operations for Transit Mission Phases

The National Aeronautics and Space Administration (NASA) has begun evaluating various mission and system components of possible implementations of what the U.S. Human Spaceflight Plans Committee (also known as the Augustine Committee) has named the flexible path (Anon., 2009). As human spaceflight missions expand further into deep space, the duration of these missions increases to the point where a dedicated crew habitat element appears necessary. There are several destinations included in this flexible path a near Earth asteroid (NEA) mission, a Phobos/Deimos (Ph/D) mission, and a Mars surface exploration mission that all include at least a portion of the total mission in which the crew spends significant periods of time (measured in months) in the deep space environment and are thus candidates for a dedicated habitat element. As one facet of a number of studies being conducted by the Human Spaceflight Architecture Team (HAT) a workshop was conducted to consider how best to define and quantify habitable volume for these future deep space missions. One conclusion reached during this workshop was the need for a description of the scope and scale of these missions and the intended uses of a habitat element. A group was set up to prepare a concept of operations document to address this need. This document describes a concept of operations for a habitat element used for these deep space missions. Although it may eventually be determined that there is significant overlap with this concept of operations and that of a habitat destined for use on planetary surfaces, such as the Moon and Mars, no such presumption is made in this document.

Hoffman, Stephen J.↗
NASA NTRSDate not supplied

The Gateway Program as Part of NASA’s Plans for Human Exploration Beyond Low Earth Orbit

This paper provides an overview and status of Gateway, humanity’s first space station in lunar orbit as a vital component of the NASA-led Artemis missions to return humans to the Moon as preparation for the first human missions to Mars. Gateway is an aggregation point in deep space for a variety of spacecraft, including the crewed Orion vehicle, the Human Landing System that will ferry astronauts to and from the lunar surface, logistics supply craft, and vehicles transiting further into deep space beyond the Earth-Moon system, such as to Mars. NASA is building on decades of partnership with space agencies on three continents and multiple commercial partners to design, build, and launch Gateway’s core elements to near-rectilinear halo orbit (NRHO) around the Moon, where it will operate for a minimum of 15 years. Gateway is humanity’s next in-space science utilization platform, and its first in deep space, with three science payloads already selected to study solar and cosmic radiation. This paper will provide an overview of the Gateway space station’s major components in various stages of development, including the Power and Propulsion Element (PPE), Habitation and Logistics Outpost (HALO), the International Habitation (I-Hab) module, ESPRIT Refueling Module (ERM), the planned airlock, advanced external robotics systems, Deep Space Logistics supply craft, and next-generation autonomous Vehicle System Manager software. It will also provide an overview of how Gateway will be utilized for science, and highlight the space station’s multilateral governance structure and international agreements.

Emma Lehnhardt↗
NASA NTRS2017

NASA's In-Space Manufacturing Project: Development of a Multimaterial, Multiprocess Fabrication Laboratory for the International Space Station

NASA's long term goal is to send humans to Mars. Over the next two decades, NASA will work with private industry to develop and demonstrate the technologies and capabilities needed to support exploration of the red planet by humans and ensure their safe return to earth. To accomplish this goal, NASA is employing a capability driven approach to its human spaceflight strategy. This approach will develop a suite of evolving capabilities which provide specific functions to solve exploration challenges. One challenge that is critical to sustainable and safer exploration is the ability to manufacture and recycle materials in space. This paper provides an overview of NASA's in-space manufacturing project, its past and current activities, and how technologies under development will ultimately culminate in a multimaterial, multiprocess fabrication laboratory ('FabLab') to be deployed on the International Space Station in the early 2020s. ISM is a critical capability for the long endurance missions NASA seeks to undertake in the coming decades. An unanticipated failure that can be adapted for in low earth orbit may result in a loss of mission in transit to Mars. In order to have a suite of functional ISM capabilities that are compatible with NASA's exploration timeline, ISM must be equipped with the resources necessary to develop these technologies and deploy them for testing prior to the scheduled de-orbit of ISS in 2024. The paper will discuss the phased approach to FabLab development, desired capabilities, and requirements for the hardware. The FabLab will move NASA and private industry significantly closer to changing historical paradigms for human spaceflight where all materials used in space are launched from earth. While the FabLab will be tested on ISS, the system is ultimately intended for use in a deep space habitat or transit vehicle.

Prater, T.↗
NASA NTRS2018

NASA's In-Space Manufacturing Project: Toward a Multimaterial Fabrication Laboratory for the International Space Station

uman space exploration to date has been limited to low Earth orbit and the moon. The International Space Station (ISS) provides a unique opportunity for NASA to partner with private industry for development and demonstration of the technologies needed to support exploration initiatives. One challenge that is critical to sustainable and safer exploration is the ability to manufacture and recycle materials in space. This paper provides an overview of NASA's in-space manufacturing (ISM) project, its past and current activities, and how technologies under development will ultimately culminate in a multimaterial fabrication laboratory ("ISM FabLab") to be deployed on the International Space Station in the early 2020s. ISM is a critical capability for the long endurance missions NASA seeks to undertake in the coming decades. An unanticipated failure that can be adapted for in low earth orbit, through a resupply launch or a return to earth, may instead result in a loss of mission while in transit to Mars. To have a suite of functional ISM capabilities that are compatible with NASA's exploration timeline, ISM must be equipped with the resources necessary to develop these technologies and deploy them for testing prior to the scheduled de-orbit of ISS in 2024. The paper provides a broad overview of ISM projects activities culminating with the Fabrication Laboratory for ISS. The FabLab will move NASA and private industry significantly closer to changing historical paradigms for human spaceflight where all materials used in space are launched from earth. While the current ISM FabLab will be tested on ISS, future systems are eventually intended for use in a deep space habitat or transit vehicle. The work of commercial companies funded under NASA's Small Business Innovative Research Program (SBIR) is also discussed, as these activities, from development of recyclable packaging for ISS to additive manufacturing capabilities for metals and electronics, could also potentially be infused into FabLab exploration capabilities as well.

Prater, Tracie↗
NASA NTRS2017

NASA's In-Space Manufacturing Project: A Roadmap for a Multimaterial Fabrication Laboratory in Space

Human space exploration to date has been limited to low Earth orbit and the moon. The International Space Station (ISS) provides a unique opportunity for NASA to partner with private industry for development and demonstration of the technologies needed to support exploration initiatives. One challenge that is critical to sustainable and safer exploration is the ability to manufacture and recycle materials in space. This paper provides an overview of NASA's in-space manufacturing (ISM) project, its past and current activities (2014-2017), and how technologies under development will ultimately culminate in a multimaterial fabrication laboratory ("ISM FabLab") to be deployed on the International Space Station in the early 2020s. ISM is a critical capability for the long endurance missions NASA seeks to undertake in the coming decades. An unanticipated failure that can be adapted for in low earth orbit, through a resupply launch or a return to earth, may instead result in a loss of mission while in transit to Mars. To have a suite of functional ISM capabilities that are compatible with NASA's exploration timeline, ISM must be equipped with the resources necessary to develop these technologies and deploy them for testing prior to the scheduled de-orbit of ISS in 2024. The presentation provides a broad overview of ISM projects activities culminating with the Fabrication Laboratory for ISS. In 2017, the in-space manufacturing project issued a broad agency announcement for this capability. Requirements of the Fabrication Laboratory as stated in the solicitation will be discussed. The FabLab will move NASA and private industry significantly closer to changing historical paradigms for human spaceflight where all materials used in space are launched from earth. While the current ISM FabLab will be tested on ISS, future systems are eventually intended for use in a deep space habitat or transit vehicle. The work of commercial companies funded under NASA's Small Business Innovative Research Program (SBIR) is also discussed, as these activities, from development of recyclable packaging for ISS to additive manufacturing capabilities for metals and electronics, could also potentially be infused into future exploration capabilities. Key data from ISM projects to date will also be summarized.

Prater, Tracie↗
NASA NTRS2012

Deep Space Habitat Concept of Operations for Extended Duration Transit Missions

NASA's Capability-Driven Framework (CDF) describes an approach for progressively extending human exploration missions farther into the Solar System for longer periods of time as allowed by developments in technology and spacecraft systems. Within this framework design reference missions (DRMs) targeted for several specific destinations are being used to assess different combinations of vehicles, operations, and advanced technologies to help understand which combination will best support expanded human exploration both efficiently and sustainably. Several of the identified destinations have been found to require missions with a round trip duration exceeding one year. These mission durations exceed the capabilities of current human-rated spacecraft if resupply from Earth is not possible. This makes the design of an efficient and reliable Deep Space Habitat (DSH) critical for reaching these destinations. The paper will describe the current understanding of DSH capabilities and functions that must be exhibited by any future habitat design for these missions. This description of the DSH is presented in the form of a concept of operation, which focuses on the functions that any DSH must provide, as opposed to a specific DSH design concept. Development of a concept of operations, based on DRM features, provides a common basis for assessing the viability of design concepts incorporating differing configurations and technologies. A study team with representation from several NASA Centers and relevant engineering and scientific disciplines collaborated to develop this DSH concept of operations for the transit phases of these missions. The transit phase of a mission is defined as the time after leaving Earth but before arrival at the destination and the time after leaving the destination but before arriving back at Earth. These transit phases were found to have many common features across all of the destinations being assessed for the CDF and thus arguing for a common concept of operations for all of the associated DRMs. The paper first describes the CDF and potential destinations being considered within this framework. DRMs representative of those currently being assessed will then be discussed to illustrate the range of capabilities that the DSH must support. The 18 functions identified by the multi-discipline analysis team are then described at a summary level. Several specific examples of the potential use for this concept of operations are described.

Hoffman, Stephen J.↗
NASA NTRS2004

Overview of the Martian radiation environment experiment

Space radiation presents a hazard to astronauts, particularly those journeying outside the protective influence of the geomagnetosphere. Crews on future missions to Mars will be exposed to the harsh radiation environment of deep space during the transit between Earth and Mars. Once on Mars, they will encounter radiation that is only slightly reduced, compared to free space, by the thin Martian atmosphere. NASA is obliged to minimize, where possible, the radiation exposures received by astronauts. Thus, as a precursor to eventual human exploration, it is necessary to measure the Martian radiation environment in detail. The MARIE experiment, aboard the 2001 Mars Odyssey spacecraft, is returning the first data that bear directly on this problem. Here we provide an overview of the experiment, including introductory material on space radiation and radiation dosimetry, a description of the detector, model predictions of the radiation environment at Mars, and preliminary dose-rate data obtained at Mars. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

NASA Program Biomedical Research and Countermeasur↗
NASA NTRS2014

Autonomous Real Time Requirements Tracing

One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the targeted system. It is envisioned that real time requirements tracing will greatly assist the movement of autoprocedures to flight software enhancing the software assurance of auto-procedures and also their acceptance as reliable commanders.

Plattsmier, George↗
NASA NTRS2014

Autonomous Real Time Requirements Tracing

One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto-Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner- TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the targeted system. It is envisioned that real time requirements tracing will greatly assist the movement of autoprocedures to flight software enhancing the software assurance of auto-procedures and also their acceptance as reliable commanders

Plattsmier, George I.↗