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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

STS flight operations - Concept versus reality

The NASA Lyndon B. Johnson Space Center Mission Operations Directorate (MOD) has the responsibility for planning, training, and implementing of flight operations in support of the National Space Transportation System (STS) Program. In this role, MOD has responsibility for the operational interface with customers and the translation of customer requirements into operating plans to satisfy their objectives. The basic objectives of flight operations are to maximize mission success, to minimize risks to the Orbiter and the crew, to decrease operating costs, and to achieve an effective balance in the application of all operational resources. In the National STS Program, to date, 20 missions have been flown and the process for planning, training, and flight operations has been thoroughly exercised. In this paper, MOD's performance is assessed, and those areas in which our initial operating concepts have been successful as well as those in which significant additional work is required are identified.

Kranz, E. F.↗
NASA NTRS1994

Orion: Design of a system for assured low-cost human access to space

In recent years, Congress and the American people have begun to seriously question the role and importance of future manned spaceflight. This is mainly due to two factors: a decline in technical competition caused by the collapse of communism, and the high costs associated with the Space Shuttle transportation system. With these factors in mind, the ORION system was designed to enable manned spaceflight at a low cost, while maintaining the ability to carry out diverse missions, each with a high degree of flexibility. It is capable of performing satellite servicing missions, supporting a space station via crew rotation and resupply, and delivering satellites into geosynchronous orbit. The components of the system are a primary launch module, an upper stage, and a manned spacecraft capable of dynamic reentry. For satellite servicing and space station resupply missions, the ORION system utilizes three primary modules, an upper stage, and the spacecraft, which is delivered to low earth orbit and used to rendezvous, transfer materials, and make repairs. For launching a geosynchronous satellite, one primary module and an upper stage are used to deliver the satellite, along with an apogee kick motor, into orbit. The system is designed with reusability and modularity in mind in an attempt to lower cost.

Elvander, Josh↗
NASA NTRS1995

Spacecraft For Transport Between The Earth And The Moon

Report proposes development of family of spacecraft for transport between Earth and Moon. Development program oriented toward evolutionary improvements of equipment with minimal redesign of hardware. Intention to develop lineage of spacecraft, designs evolved to adapt to changing requirements and fabricated on long-lived production lines. Conceptual future enhancements include different propulsion systems, transfer habitats, crew cabs, and aerobrakes for reentry to atmoshphere of Earth.

Capps, Stephen↗
NASA NTRS1991

A Rocket Powered Single-Stage-to-Orbit Launch Vehicle With U.S. and Soviet Engineers

A single-stage-to-orbit launch vehicle is used to assess the applicability of Soviet Energia high-pressure-hydrocarbon engine to advanced U.S. manned space transportation systems. Two of the Soviet engines are used with three Space Shuttle Main Engines. When applied to a baseline vehicle that utilized advanced hydrocarbon engines, the higher weight of the Soviet engines resulted in a 20 percent loss of payload capability and necessitated a change in the crew compartment size and location from mid-body to forebody in order to balance the vehicle. Various combinations of Soviet and Shuttle engines were evaluated for comparison purposes, including an all hydrogen system using all Space Shuttle Main Engines. Operational aspects of the baseline vehicle are also discussed. A new mass properties program entitles Weights and Moments of Inertia (WAMI) is used in the study.

MacConochie, Ian O.↗
NASA NTRS2017

Robust Exploration and Commercial Missions to the Moon Using NTR LANTR Propulsion and Lunar-Derived Propellants

The nuclear thermal rocket (NTR) has frequently been identified as a key space asset required for the human exploration of Mars. This proven technology can also provide the affordable access through cislunar space necessary for commercial development and sustained human presence on the Moon. In his post-Apollo Integrated Space Program Plan (1970-1990), Wernher von Braun, proposed a reusable nuclear thermal propulsion stage (NTPS) to deliver cargo and crew to the Moon to establish a lunar base before undertaking human missions to Mars. The NTR option was selected by von Braun because it was a demonstrated technology capable of generating both high thrust and high specific impulse (Isp 900 s) twice that of todays best chemical rockets. In NASAs Mars Design Reference Architecture (DRA) 5.0 study, the crewed Mars transfer vehicle used three 25 klbf Pewee engines the smallest and highest performing engine tested in the Rover program along with graphite composite fuel. Smaller, lunar transfer vehicles consisting of a NTPS using three approximately 16.5 klbf Small Nuclear Rocket Engines (SNREs), an in-line propellant tank, plus the payload can enable a variety of reusable lunar missions. These include cargo delivery and crewed lunar landing missions. Even weeklong tourism missions carrying passengers into lunar orbit for a day of sightseeing and picture taking are possible. The NTR can play an important role in the next phase of lunar exploration and development by providing an affordable in-space lunar transportation system (LTS) that can allow initial outposts to evolve into settlements supported by a variety of commercial activities such as in-situ propellant production used to supply strategically located propellant depots and transportation nodes. The utilization of iron-rich volcanic glass or lunar polar ice (LPI) deposits (each estimated at billions of metric tons) for propellant production can significantly reduce the launch mass requirements from Earth and can enable reusable, surface-based lunar landing vehicles (LLVs) using liquid oxygen/hydrogen (LOX/LH2) chemical rocket engines. Afterwards, LOX/LH2 propellant depots can be established in lunar equatorial and polar orbits to supply the LTS. At this point a modified version of the conventional NTR called the LOX-augmented NTR, or LANTR would be introduced into the LTS allowing bipropellant operation and leveraging the mission benefits of refueling with lunar-derived propellants for Earth return. The bipropellant LANTR engine utilizes the large divergent section of its nozzle as an afterburner into which oxygen is injected and supersonically combusted with nuclear preheated hydrogen emerging from the engines choked sonic throat essentially scramjet propulsion in reverse. By varying the oxygen-to-hydrogen mixture ratio, LANTR engines can operate over a range of thrust and Isp values while the reactor core power level remains relatively constant. Eventually, a LANTR-based LTS can enable a rapid commuter shuttle with one-way trip times to and from the Moon ranging from 36 to 24 hours. Even if only 1 of the extracted propellant from identified volcanic glass and polar ice deposits were available for use in lunar orbit, such a supply could support daily commuter flights to the Moon for many thousands of years! An evolutionary mission architecture is outlined and a variety of lunar missions and transfer vehicle designs are examined, along with the increasing demands on propellant production as mission complexity increases. A comparison of vehicle features and engine operating characteristics, for both NTR and LANTR engines, is also provided along with a brief discussion on the propellant production issues associated with using volcanic glass and LPI as source material.

Spacecraft design↗
NASA NTRSDate not supplied

Creating a Wastewater Technology ‘Toolbox’ for Space Exploration ECLSS

Life Support Systems (LSS) are essential for manned spaceflight; without them, humans would not survive. Upcoming long-duration missions demand robust environmental control LSS (ECLSS) due to their insolation and limited prospect for immediate resupply. As part of LSS, water purification systems will require high reliability, sustainability, and efficiency due to transport mass limitations, because routine water delivery will be very difficult and costly to resupply future habitats. This suggests a highly effective treatment method and reuse of every wastewater source. A variety of wastewater streams are generated by crew, and although not all are currently treated, habitat success will require each stream to be treated and utilized as a ‘resource’ rather than 'waste’. These wastewater streams include human wastewater (urine, feces), food waste (plate waste, inedible plant biomass), humidity condensate, hygiene water (shower, oral, handwash), and laundry. Proven technologies are often relied upon due to long-term operations. For future, longer-term missions, this paradigm must shift to include technologies based on meeting mission requirements rather than sacrificing productivity in lieu of proven existing technology capabilities. Many physical, chemical, and biological water-processing technologies are proven and established for terrestrial applications. Herein, these technologies were collected into a ‘toolbox’ to perform possible functions towards effective water purification steps in reduced gravity. Selection criteria are dependent on approach (physical, chemical, or biological), complexity/components, terrestrial performance, and potential applicability to space life support. Utilization of this ‘toolbox’ approach provides a streamline methodology for technology development and down-selection into future architecture in direct response to the dynamic space life support requirements. Establishing the ‘toolbox’ also provides organized and efficient identification of the most appropriate technologies. From there, the technologies with the largest potential to be configured for mission requirements can be further developed and appropriately assessed. This presentation seeks to provide a comprehensive review of space life support water purification requirements and challenges, as well as to present a ‘toolbox’ methodology of available technologies to aid in the difficult process of selecting appropriate LSS water purification for short and long-term NASA mission architectures.

Luke Roberson↗
NASA NTRSDate not supplied

How To Train Your Dragon (and Vice Versa) – Human Spaceflight Research and The First Commercial Crews

The International Space Station has been an orbiting laboratory for human spaceflight research for over 20 years. NASA’s human research implementation teams have worked to develop, refine, and execute pre-, in-, and post-flight sessions to collect critical research data that will enable future spaceflight missions. The teams have worked closely with the spaceflight vehicle teams, including those for Soyuz and the now retired Space Shuttle vehicles, to successfully conduct this research. As NASA has transitioned to commercial vehicles for transport of crews to the ISS, the implementation teams have expanded their scope to include the SpaceX and upcoming Boeing vehicles. This session will focus on the unique implementation needs for the first available commercial platform, SpaceX. We will identify implementation adjustments made to accommodate the SpaceX Dragon system, including crew training and preflight baseline data collection, inflight operations tied to landing, and postflight planning and crew testing, as well as offer lessons learned from the past three SpaceX long-duration crew missions. Representatives from the Flight Operations Directorate, including the Astronaut Office and the vehicle recovery team, will also provide their perspectives on this new system, and how it affects their work with the human research community. A panel discussion with dedicated time for Q&A will follow.

Pasha Morshedi↗
NASA NTRS1987

Assessment of mixed fleet potential for space station launch and assembly

Reductions in expected STS flight rates of the Space Shuttle since the 51-L accident raise concerns about the ability of available launch capacity to meet both payload-to-orbit and crew rotation requirements for the Space Station. In addition, it is believed that some phases of Station build-up could be expedited using unmanned launch systems with significantly greater lift capacity than the STS. Examined is the potential use of expendable launch vehicles (ELVs), yet-to-be-developed unmanned shuttle-derived vehicles (SDVs), and international launch vehicles for meeting overall launch requirements to meet Space Station program objectives as defined by the 1986 Critical Evaluation Task Force (CETF). The study concludes that use of non-STS transportation can help meet several important program objectives as well as reduce the total number of STS flights. It also finds, however, that reduction of Space Station-dedicated STS flights below 8 per year forces a reduction in Station crew size assuming the CETF 90 day crew stay time baseline and seriously impairs scientific utilization of the Station.

Deryder, L. J.↗
NASA NTRS1988

Microgravity particle reduction system

The Controlled Ecological Life Support System (CELSS) project, sponsored by NASA, is assembling the knowledge required to design, construct, and operate a system which will grow and process higher plants in space for the consumption by crew members of a space station on a long term space mission. The problem of processing dry granular organic materials in microgravity is discussed. For the purpose of research and testing, wheat was chosen as the granular material to be ground into flour. Possible systems which were devised to transport wheat grains into the food processor, mill the wheat into flour, and transport the flour to the food preparation system are described. The systems were analyzed and compared and two satisfactory systems were chosen. Prototypes of the two preferred systems are to be fabricated next semester. They will be tested under simulated microgravity conditions and revised for maximum effectiveness.

Brandon, Vanessa↗
NASA NTRS1992

The HL-20 Personnel Launch System

A lifting-body approach to the design of a personnel launch system spacecraft for Space Station crew rotation missions is presented. Recent study findings in the areas of wind tunnel tests, landing dynamics, handling qualities, and abort are summarized. HL-20, which is designed for safe and reliable operations, has improved operability, maintainability, and affordability as compared to current manned transportation operations. The high lift-to-drag ratio of the HL-20 provides significant advantages in reduced g-loads during entry, high crossrange capability, ability to fly to landing sites over an extensive part of the earth, and multiple landing opportunities per day at specific landing sites. Pilot ratings of the flying qualities are at level 1 on the Cooper-Harper scale. Attention is also given to a streamlined management approach to HL-20 PLS development and operations which are presently under study.

Talay, Theodore A.↗
NASA NTRS2011

Making Human Spaceflight Practical and Affordable: Spacecraft Designs and their Degree of Operability

As we push toward new and diverse space transportation capabilities, reduction in operations cost becomes increasingly important. Achieving affordable and safe human spaceflight capabilities will be the mark of success for new programs and new providers. The ability to perceive the operational implications of design decisions is crucial in developing safe yet cost competitive space transportation systems. Any human spaceflight program - government or commercial - must make countless decisions either to implement spacecraft system capabilities or adopt operational constraints or workarounds to account for the lack of such spacecraft capabilities. These decisions can benefit from the collective experience that NASA has accumulated in building and operating crewed spacecraft over the last five decades. This paper reviews NASA s history in developing and operating human rated spacecraft, reviewing the key aspects of spacecraft design and their resultant impacts on operations phase complexity and cost. Specific examples from current and past programs - including the Space Shuttle and International Space Station - are provided to illustrate design traits that either increase or increase cost and complexity associated with spacecraft operations. These examples address factors such as overall design performance margins, levels of redundancy, degree of automated failure response, type and quantity of command and telemetry interfaces, and the definition of reference scenarios for analysis and test. Each example - from early program requirements, design implementation and resulting real-time operations experience - to tell the end-to-end "story" Based on these experiences, specific techniques are recommended to enable earlier and more effective assessment of operations concerns during the design process. A formal method for the assessment of spacecraft operability is defined and results of such operability assessments for recent spacecraft designs are provided. Recent experience in applying these techniques to Orion spacecraft development is reviewed to highlight the direct benefits of early operational assessment and collaborative development efforts.

Crocker, Alan R.↗
NASA NTRS2011

Performance of Airborne Precision Spacing Under Realistic Wind Conditions

With the expected worldwide increase of air traffic during the coming decade, both the Federal Aviation Administration s (FAA s) Next Generation Air Transportation System (NextGen), as well as Eurocontrol s Single European Sky ATM Research (SESAR) program have, as part of their plans, air traffic management solutions that can increase performance without requiring time-consuming and expensive infrastructure changes. One such solution involves the ability of both controllers and flight crews to deliver aircraft to the runway with greater accuracy than is possible today. Previous research has shown that time-based spacing techniques, wherein the controller assigns a time spacing to each pair of arriving aircraft, is one way to achieve this goal by providing greater runway delivery accuracy that produces a concomitant increase in system-wide performance. The research described herein focuses on a specific application of time-based spacing, called Airborne Precision Spacing (APS), which has evolved over the past ten years. This research furthers APS understanding by studying its performance with realistic wind conditions obtained from atmospheric sounding data and with realistic wind forecasts obtained from the Rapid Update Cycle (RUC) short-range weather forecast. In addition, this study investigates APS performance with limited surveillance range, as provided by the Automatic Dependent Surveillance-Broadcast (ADS-B) system, and with an algorithm designed to improve APS performance when an ADS-B signal is unavailable. The results presented herein quantify the runway threshold delivery accuracy of APS un-der these conditions, and also quantify resulting workload metrics such as the number of speed changes required to maintain spacing.

Wieland, Frederick↗
NASA NTRS2013

NASA's Space Launch System: One Vehicle, Many Destinations

The National Aeronautics and Space Administration's (NASA's) Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is making progress toward delivering a new capability for exploration beyond Earth orbit. Developed with the goals of safety, affordability, and sustainability in mind, the SLS rocket will start its missions in 2017 with 10 percent more thrust than the Saturn V rocket that launched astronauts to the Moon 40 years ago. From there it will evolve into the most powerful launch vehicle ever flown, via an upgrade approach that will provide building blocks for future space exploration and development. The International Space Exploration Coordination Group, representing 12 of the world's space agencies, has created the Global Exploration Roadmap, which outlines paths toward a human landing on Mars, beginning with capability-demonstrating missions to the Moon or an asteroid. The Roadmap and corresponding NASA research outline the requirements for reference missions for all three destinations. This paper will explore the capability of SLS to meet those requirements and enable those missions. It will explain how the SLS Program is executing this development within flat budgetary guidelines by using existing engines assets and developing advanced technology based on heritage systems, from the initial 70 metric ton (t) lift capability through a block upgrade approach to an evolved 130-t capability. It will also detail the significant progress that has already been made toward its first launch in 2017. The SLS will offer a robust way to transport international crews and the air, water, food, and equipment they will need for extended trips to explore new frontiers. In addition, this paper will summarize the SLS rocket's capability to support science and robotic precursor missions to other worlds, or uniquely high-mass space facilities in Earth orbit. As this paper will explain, the SLS is making measurable progress toward becoming a global infrastructure asset for robotic and human scouts of all nations by providing the robust launch capability to deliver sustainable solutions for space exploration.

May, Todd A.↗
NASA NTRS2000

Advances in Space Transportation Technology Toward the NASA Goals

NASA has set goals to increase safety by one hundred times while reducing cost tenfold over the next decade. This dramatic increase in safety will come by departing from a past emphasis on cost and performance to a new paradigm of safety and reliability, which, in turn, will drive down cost. To accomplish this, vehicle systems must be inherently reliable, functionally redundant wherever practical and designed to minimize or eliminate catastrophic failure modes. Over the next twenty-five years, NASA has set goals to increase safety ten thousand times while reducing cost one hundred fold. Safety will increase towards today's airline safety and the low price per flight has the potential to enable a 15-fold increase in the size of the current projected space launch market. This level of improvement is comparable to the developments in the 1970s in the computer microprocessor when microchips went from hundreds of thousands to tens of thousands of dollars - hailing the era of the personal computer. In order to achieve such ambitious cost goals, today's partial and fully expendable rockets must be replaced by fully reusable systems. A RLV can eliminate assembly and checkout of the large number of complex interfaces on today's Space Shuttle. Full reusability will eliminate the necessity to throw away expensive hardware and the need for on-going production. Systems in ten years will have to accommodate 50 to 100 missions per year and could be commercially certified for hundreds of flights. In twenty-five years, the number of flights per year could jump to over 1,000, which will require certification for thousands of flights. The large increase in flights per year will demand that current operations and maintenance procedures be revolutionized. Unlike the current shuttle, which requires several thousand personnel over five months to process, the next generation system must be turned around in one week with less than one hundred personnel. In contrast to the rigorous disassembly and inspections required for the Space Shuttle's subsystems, the next generation vehicle's on-board health monitoring systems will could tell the ground crews which systems need replacement before landing. In twenty-five years, vehicles will be re-flown within one with crews numbering less than one hundred. Fully automated ground processing systems must require only a handful of personnel to launch the vehicle. Due to the increased intelligence of on-board systems, only cursory walk-around inspections would be required between flights An assessment of the progress in breakthrough technologies toward these goals by the NASA Advanced Space Transportation Program is presented. These breakthrough technologies include combined rocket and air breathing propulsion, high strength lightweight structures, high temperature materials, vehicle health management, and flight operations.

Lyles, Garry M.↗
NASA NTRS1980

A survey of new technology for cockpit application to 1990's transport aircraft simulators

Two problems were investigated: inter-equipment data transfer, both on board the aircraft and between air and ground; and crew equipment communication via the cockpit displays and controls. Inter-equipment data transfer is discussed in terms of data bus and data link requirements. Crew equipment communication is discussed regarding the availability of CRT display systems for use in research simulators to represent flat panel displays of the future, and of software controllable touch panels.

Holt, A. P., Jr.↗
NASA NTRSDate not supplied

Recommended Crew Systems Capabilities for a 30 to 90 Day Four-Crew Lunar Surface Mission

For any given surface mission duration, there exists a set of surface capabilities necessary to sustain a four-person crew for the length of time the crew is on the surface. Identifying these capabilities is important to mission planners and spacecraft design engineers responsible for lunar surface habitation elements, who need to know which systems and capabilities must be prioritized for the vehicles they are designing. However, simply identifying the surface capabilities does not necessarily equal a viable surface configuration. These capabilities may or may not satisfy stakeholder expectations or even permit completion of mission objectives. Lunar lander cargo mass constraints are a powerful forcing function that requires significant efforts to reduce the mass of all surface elements, including those supporting crew habitation. The required capabilities do increase as a function of mission duration, but it is a nonlinear growth. There are key points in mission duration, beyond which certain additional capabilities are needed. This forms bands of capability between each point. Within a given band, the same functional capabilities are needed, and the only scaling is that associated with daily consumables. The next higher band requires additional capabilities. This paper will focus on those capabilities needed for missions of 30-90 days. It should be noted that there are some uncertainties interpreting NASA requirements that require capabilities after a certain number of days, as typically this refers to number of days in space, not number of days on the lunar surface. Depending on transportation architecture, the number of days between Earth launch and lunar surface landing may vary, therefore impacting when certain required capabilities are implemented. However, activities to prepare humans for missions to Mars and commercial interest in lunar development may drive progressive increases in surface duration. Missions up to 30 days are expected to follow the initial 6.5-day surface missions and there may be commercial interest in extending to even greater durations. This paper will examine the potential case of a 30-90-day surface mission duration with respect to the systems necessary to support crew living and working on the lunar surface.

Habitat↗
NASA NTRS2008

The Pressurized Logistics Module: Providing Consumables and Resupply Logistics to the Lunar Surface for a Long-duration Manned Mission

In response to President Bush s 2004 Vision for Space Exploration initiative, NASA established an agency-wide Lunar Architecture Team (LAT) to develop the high-level requirements, assumptions, ground-rules and objectives for a manned mission to the moon. During Phase II of the evaluation, the Habitation Focus Element Group was directed to conceptually develop and design a Pressurized Logistics Module (PLM). The PLM task was delivered with one major requirement: to derive a system with minimal mass and cost, and a maximum, functional, internal volumetric area in order to provide the maximum amount of consumables, supportability and logistic re-supply for a crew of four to the Lunar surface with an overall integrated maximum weight of 5200kg. The PLM was derived from the Habitation Group s "mini-Hab" option. This concept required that the PLM have an aluminum-clad graphite epoxy external truss, utilized for increased mobility and stability, which would encompass a 2.7 meter diameter pressurized aluminum-lithium cylinder. Several trade studies and analyses were performed to determine the final length and orientation of the module, the number of systems required to maintain the PLM, and the number of hatches/mating mechanisms which would successfully and efficiently meet the requirements. Of the five specific configurations assessed, the PLM was determined to have a 3 meter by 3 meter by 5 meter external truss with a 2.7 meter diameter and 5 meter long horizontal, pressurized cylinder with one hatch/mating mechanism on one end cone. Two major assumptions aided in the formulation of the technical baseline: 1) the PLM should be sustainable for up to 18 months on the Lunar Lander without connection to its final destination, the Lunar Outpost, and 2) it must be self-sufficient to withstand a maximum eight hour transit from the Lander to the Outpost. Per these assumptions, eight major systems constitute the PLM: structures, passive mating, protection, power, thermal, avionics, life support and outfitting. Including a conservative 20% growth, the overall estimated tare weight for the PLM was determined to be 2181kg. The tare weight of the design allowed the available internal volume of the cylinder with a 0.20 meter high floor to transport the maximum of either 176 single Crew Transfer Bags (CTBs) or 3019kg.

Carpenter, Amanda↗
NASA NTRSDate not supplied

NASA's Habitation Development Status: Current Concepts and ISRU Opportunities

Introduction: The National Aeronautics and Space Administration (NASA) is embarking on a bold journey to return humankind to the Moon and onward to Mars with innovative commercial, international, and academic partnerships. Under the Artemis series of missions, NASA seeks to establish sustained human exploration of deep space through an objectives-based approach. This approach drives the identification of needed system functionality and the current and future capabilities which will eventually allow humanity to sustainably live beyond Earth. Providing evolvable and scalable habitation is a cornerstone function that calls for the collection and integration of current, developmental, and future technologies that can meet near-term exploration needs while growing into long-term sustained presence. NASA is advancing in-space habitation through its Next Space Technologies for Exploration Partnerships (NextSTEP) model while designing lunar, Mars transit, and Mars surface habitat government reference concepts for Artemis missions. These efforts have unveiled possible near-term opportunities for the in-space resource utilization community if human habitation is considered a future customer of space resources. NextSTEP Habitation Development: NASA is closely working with commercial partners under its NextSTEP Appendix A model to advance habitation systems in the arena of inflatable and composite habitation structures. Such efforts promise efficiencies in volumetric packaging and overall spacecraft mass respectively. Recent testing by commercial partners have helped to quantify possible failure mechanisms for inflatable structures while advancing their technology towards eventual flight certification. The advancement of such Class II habitation structures, in which the habitat is only fully deployed once in-space or on a planetary surface, is critical to providing increased habitable volume for long-duration missions with no additional mass penalties. The progression of such technology is infused into NASA’s government reference concepts for notional deep space habitation concepts. Current Government Reference Concepts: To best inform the formulation of future collaborative solicitations, NASA employs the practice of internally developing reference concepts for future exploration elements. These concepts aid in identifying the functions and capabilities needed to complete NASA missions as well as feasible solutions within the timeframe needed. Government reference concepts for a lunar Surface Habitat, Mars Transit Habitat, and Mars Sur-face Habitat are continuously being developed and updated to better guide the Agency’s overall exploration architecture. Lunar Surface Habitat. As NASA returns to the Moon, it is evaluating possible lunar surface habitation concepts. The Surface Habitat (SH) reference concept entails a hybrid metallic-inflatable structure capable of initially housing two crew for surface stays of up to 30 days in duration. While initial missions may span ~7 days in duration, consideration is being given to expanding SH’s capability to support a crew of four for up to 60 days over its 15-year design life. Functionally, the SH serves as a ‘hub’ for all Artemis crewed surface operations, providing internal volume for maintenance, medical, logistics, science utilization, and extravehicular activity (EVA) support in addition to core habitation functionality such as environmental control and life support (ECLS) and power generation and distribution among many others. Additionally, NASA has entered a study agreement with the Italian Space Agency (Agenzia Spaziale Italiana – ASI) to investigation a possible Multi-Purpose Habitat (MPH) as an additional or augmenting habit-able element for the lunar surface. Mars Transit Habitat. NASA’s current architectural concept for initial human missions to Mars entails the utilization of a transit habitat (TH) to transport a four-person crew to and from Mars orbit, departing from and returning to a lunar near-rectilinear halo orbit (NRHO), over the course of a ~1,200-day mission. While holding a similar 15-year design lifetime, TH will also support a series of analog mission activities in NRHO to gradually test the systems and interaction with lunar surface elements, some of which may be adapted for Mars surface exploration. Holding similar functional capabilities as SH, TH is sized to support much longer durations in space and greater logistical independence. Mars Surface Habitat. NASA is still exploring the concept of operations for initial crewed missions to Mars. As such, the Mars Surface Habitat (MSH) concept is still in its infancy as options for mobile, pressurized habitation and stationary habitats are being explored. It is expected MSH will leverage heavily from the lunar SH and possible lunar pressurized rover, however the very different Martian environment will likely necessitate modifications. ISRU Opportunities: Despite the advancements under NASA’s NextSTEP habitation work and continually optimized reference concepts, NASA is facing near-term mass and power challenges that may create opportunities to the ISRU community by providing yet another possible customer for space resources. While NASA desires to use regenerative ECLS systems (ECLSS) for all habitation concepts, their operation comes with initial mass penalties and maintenance overheads when compared to simpler open-loop architectures. Because of this, NASA is currently pro-posing an open-loop, consumables-based architecture for its surface habitats to achieve initial launch and delivery lander mass targets while scarring for the in-corporation of regenerative ECLSS to meet longer mission durations and sustained presence. With such an architecture, oxygen and potable water are needed consumables, which initial ISRU systems may be able to provide in a pilot capacity. Although the TH is expecting to utilize regenerative ECLSS, advancements in lunar surface-based ISRU and possible re-supply of spacecraft in lunar or Mars orbit could significantly reduce the logistical need for ECLSS related spares on TH and possibly allow a similar open-loop and consumables-based architecture. In addition to ECLSS mass concerns, the SH is facing challenges with energy storage to support operations over periods of darkness exceeding 100 hours. Both battery and fuel cell-based power architectures are being traded, opening options for external power generation and energy storage. One possibility is ISRU-produced H2 and O2 feeding external primary fuel cell systems which could supplement habitation power generation while reducing initial mass and volume until much more powerful fission power systems might be deployed. Conclusion: Significant advancements are being made in evolvable habitation concepts that span from near-term technologies, such as inflatable structures under NextSTEP, to potentially revolutionary capabilities like the lunar surface construction as funded through the Moon-to-Mars Planetary Autonomous Construction Technologies (MMPACT) project. As NASA investigates both heritage capabilities and rap-idly advancing, disruptive technologies, there are likely many near-term opportunities for initial ISRU capabilities to significantly aid human habitation and increase self-sufficiency beyond Earth.

habitation↗