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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 NTRS2015

Probability of Loss of Crew Achievability Studies for NASA's Exploration Systems Development

Over the last few years, NASA has been evaluating various vehicle designs for multiple proposed design reference missions (DRM) beyond low Earth orbit in support of its Exploration Systems Development (ESD) programs. This paper addresses several of the proposed missions and the analysis techniques used to assess the key risk metric, probability of loss of crew (LOC). Probability of LOC is a metric used to assess the safety risk as well as a design requirement. These assessments or studies were categorized as LOC achievability studies to help inform NASA management as to what "ball park" estimates of probability of LOC could be achieved for each DRM and were eventually used to establish the corresponding LOC requirements. Given that details of the vehicles and mission are not well known at this time, the ground rules, assumptions, and consistency across the programs become the important basis of the assessments as well as for the decision makers to understand.

Boyer, Roger L.↗
NASA NTRS2012

Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified as the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast spectrum reactor and engine designs employing refractory metal alloy fuel types were proposed and designed, but none were built. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art graphite based fuel design incorporating lessons learned from the very successful technology development program. The SNRE was a nominal 16,000-lbf thrust engine originally intended for unmanned applications with relatively short engine operations and the engine and stage design were constrained to fit within the payload volume of the then planned space shuttle. The SNRE core design utilized hexagonal fuel elements and hexagonal structural support elements. The total number of elements can be varied to achieve engine designs of higher or lower thrust levels. Some variation in the ratio of fuel elements to structural elements is also possible. Options for SNRE-based engine designs in the 25,000-lbf thrust range were described in a recent (2010) Joint Propulsion Conference paper. The reported designs met or exceeded the performance characteristics baselined in the DRA 5.0 Study. Lower thrust SNRE-based designs were also described in a recent (2011) Joint Propulsion Conference paper. Recent activities have included parallel evaluation and design efforts on fast spectrum engines employing refractory metal alloy fuels. These efforts include evaluation of both heritage designs from the Argonne National Laboratory (ANL) and General Electric Company GE-710 Programs as well as more recent designs. Results are presented for a number of not-yet optimized fast spectrum engine options.

Schnitzler, Bruce G.↗
NASA NTRS2013

Near-Earth Asteroid Retrieval Mission (ARM) Study

The Asteroid Redirect Mission (ARM) concept brings together the capabilities of the science, technology, and the human exploration communities on a grand challenge combining robotic and human space exploration beyond low Earth orbit. This paper addresses the key aspects of this concept and the options studied to assess its technical feasibility. Included are evaluations of the expected number of potential targets, their expected discovery rate, the necessity to adequately characterize candidate mission targets, the process to capture a non-cooperative asteroid in deep space, and the power and propulsion technology required for transportation back to the Earth-Moon system. Viable options for spacecraft and mission designs are developed. Orbits for storing the retrieved asteroid that are stable for more than a hundred years, yet allow for human exploration and commercial utilization of a redirected asteroid, are identified. The study concludes that the key aspects of finding, capturing and redirecting an entire small, near-Earth asteroid to the Earth-Moon system by the first half of the next decade are technically feasible. The study was conducted from January 2013 through March 2013 by the Jet Propulsion Laboratory (JPL) in collaboration with Glenn Research Center (GRC), Johnson Space Center (JSC), Langley Research Center (LaRC), and Marshall Space Flight Center (MSFC).

Solar Electric Propulsion (SEP)↗
NASA NTRS2014

2014 Decompression Sickness/Extravehicular Activity Risks Standing Review Panel

The 2014 Decompression Sickness (DCS)/Extravehicular Activity (EVA) Risks Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on November 4 - 5, 2014. The SRP reviewed the Research Plans for The Risk of Decompression Sickness and the Risk of Injury and Compromised Performance due to EVA Operations, as well as the Evidence Reports for both of these Risks. The SRP found that the NASA DCS/EVA team did an excellent job of presenting their research plans. The SRP considers it critical that NASA proceeds with the high priority tasks identified in this report (DCS1, DCS3, DCS5). The highest priority is to determine the acceptable DCS and hypoxia risk associated with the planned human exploration beyond low Earth orbit. The risk of DCS is highly dependent upon the pressure within the exploration vehicle. If slightly more hypoxia is permitted then (even with the same percentage of oxygen) the pressure within the exploration vehicle can be lowered thus further mitigating the risk of DCS. The second highest priority is to test and validate the recommended 8.2psi/34% O2 atmosphere. Development of procedures and equipment for human exploration missions are very limited until the results of this testing are completed. The SRP also suggests that DCS7 be separated into two Gaps. Gap DCS7 should deal with DCS treatment while a new Gap should be created to deal with the long-term effects of DCS. The SRP also encourages NASA to increase collaboration with other organizations and pool resources where possible. The current NASA DCS/EVA team has the extensive expertise and a wealth of knowledge in this area. The SRP suggests that increased manpower for this team would be highly productive.

Steinberg, Susan↗
NASA NTRS2010

Earth Return Navigation Analysis for Manned Spacecraft Using Optical and Radiometric Measurements

Future manned space missions will travel beyond low Earth orbit with more stringent navigation requirements and fewer navigation resources than used for the Apollo Program of the 1960s. A study has been performed to assess radiometric and optical tracking capabilities necessary to meet nominal and contingency Earth entry flight path angle requirements. Results indicate that 3 tracking stations will be insufficient for meeting nominal entry requirements, while the performance of a 6 station architecture is dependent on the entry geometry. Optical tracking results indicate that a narrow-angle camera is required for satisfying contingency Earth return requirements.

GN&C↗
NASA NTRS2011

IVGEN

The Exploration Medical Capabilities Element of NASA's Human Research Program chartered the IV fluid GENeration (IVGEN) project at the NASA Glenn Research Center to develop a system that could produce IV fluid in a microgravity environment meeting USP standards. NASA's flight surgeons have identified medical conditions likely to arise during exploration missions of various length and distance from the earth. Adequately treating some of those conditions will require the ability to utilize Intravenous (IV) therapy to either serve as a method for delivering pharmaceuticals that can only be administered via that route, or to hydrate patients that are unable to hydrate themselves. Given that need, NASA currently maintains a reserve of IV fluid on ISS sufficient to treat an astronaut until they can be returned to earth, which is generally within 24 hours. Because such a rapid return will not be an designed to produce United States Pharmacopeia ( USP) grade IV fluid in a reduced gravity p option for missions extending beyond low earth orbit, NASA must either fly as many as 100 liters of IV fluid, with a total mass of 100 Kg, or provide systems that can use vehicle resources to produce such fluid if it is needed. The IVGEN hardware, a compact water purification and mixing system, was environment using available resources.

DeVon, Griffin↗
NASA NTRS2015

Advanced Oxygen Recovery via Series-Bosch Technology

Oxygen recovery from metabolically-produced carbon dioxide (CO2) is of critical importance for long-duration manned space missions beyond low Earth orbit. On the International Space Station (ISS), oxygen is provided to the crew through electrolysis of water in the Oxygen Generation Assembly (OGA). Prior to 2011, this water was entirely resupplied from Earth. A CO2 Reduction Assembly based on the Sabatier reaction (1) was developed by Hamilton Sundstrand and delivered to ISS in 2010. The unit recovers oxygen by reducing metabolic CO2 with diatomic hydrogen (H2) to produce methane and product water. The water is cleaned by the Water Purification Assembly and recycled to the OGA for continued oxygen production. The methane product is vented overboard.

Abney, Morgan B.↗
NASA NTRS2015

SLS-Derived Lab- Precursor to Deep Space Human Exploration

Plans to send humans to Mars are in the works and the launch system is being built. Are we ready? Transportation, entry, landing, and surface operations have been successfully demonstrated for robotic missions. However, for human missions, there are significant, potentially show-stopping issues. These issues, called Strategic Knowledge Gaps (SKGs), are the unanswered questions concerning long duration exploration Beyond low Earth Orbit (BEO). The gaps represent a risk of loss of life or mission and because they require extended exposure to the weightless environment outside of earth's protective geo-magnetic field, they cannot be resolved on Earth or on the International Space Station (ISS). Placing a laboratory at a relatively close and stable lunar Distant Retrograde Orbit (DRO) provides an accessible location with the requisite environmental conditions for conducting SKG research and testing mitigation solutions. Configurations comprised of multiple 3 m and 4.3 m diameter modules have been studied but the most attractive solution uses elements of the human Mars launch vehicle or Space Launch System (SLS) for a Mars proving ground laboratory. A shortened version of an SLS hydrogen propellant tank creates a Skylab-like pressure vessel that flies fully outfitted on a single launch. This not only offers significant savings by incorporating SLS pressure vessel development costs but avoids the expensive ISS approach using many launches with substantial on-orbit assembly before becoming operational. One of the most challenging SKGs is crew radiation protection; this is why SKG laboratory research is combined with Mars transit habitat systems development. Fundamentally, the two cannot be divorced because using the habitat systems for protection requires actual hardware geometry and material properties intended to contribute to shielding effectiveness. The SKGs are difficult problems. The solutions to these problems are not obvious; they require integrated, iterative, and multi-disciplinary development. A lunar DRO lab built from SLS elements enables an early and representative transit habitat test bed necessary for closing gaps before sending humans on a 1,000-day Mars mission.

Griffin, Brand M.↗
NASA NTRS2014

Lunar Station: The Next Logical Step in Space Development

The International Space Station (ISS) is the product of the efforts of sixteen nations over the course of several decades. It is now complete, operational, and has been continuously occupied since November of 20001. Since then the ISS has been carrying out a wide variety of research and technology development experiments, and starting to produce some pleasantly startling results. The ISS has a mass of 420 metric tons, supports a crew of six with a yearly resupply requirement of around 30 metric tons, within a pressurized volume of 916 cubic meters, and a habitable volume of 388 cubic meters. Its solar arrays produce up to 84 kilowatts of power. In the course of developing the ISS, many lessons were learned and much valuable expertise was gained. Where do we go from here? The ISS offers an existence proof of the feasibility of sustained human occupation and operations in space over decades. It also demonstrates the ability of many countries to work collaboratively on a very complex and expensive project in space over an extended period of time to achieve a common goal. By harvesting best practices and lessons learned, the ISS can also serve as a useful model for exploring architectures for beyond low-­‐ earth-­‐orbit (LEO) space development. This paper will explore the concept and feasibility for a Lunar Station. The Station concept can be implemented by either putting the equivalent capability of the ISS down on the surface of the Moon, or by developing the required capabilities through a combination of delivered materials and equipment and in situ resource utilization (ISRU). Scenarios that leverage existing technologies and capabilities as well as capabilities that are under development and are expected to be available within the next 3-­5 years, will be examined. This paper will explore how best practices and expertise gained from developing and operating the ISS and other relevant programs can be applied to effectively developing Lunar Station.

Lunar↗
NASA NTRS2015

Micro-scale Plasma Arc Gasification for Waste Treatment and Energy Production Project

As NASA continues to develop technology for spaceflight beyond low earth orbit, we must develop the right systems for sustaining human life on a long duration or planetary mission. Plasma arc gasification (PAG) is an energy efficient mechanism of waste management for power generation and synthetic gas(syngas) production.

Technology Portfolio System↗
NASA NTRS2016

Psychological Support Operations and the ISS One-Year Mission

Since NASA began human presence on the International Space Station (ISS) in November 1998, crews have spent two to seven months onboard. In March 2015 NASA and Russia embarked on a new era of ISS utilization, with two of their crewmembers conducting a one-year mission onboard ISS. The mission has been useful for both research and mission operations to better understand the human, technological, mission management and staffing challenges that may be faced on missions beyond Low Earth Orbit. The work completed during the first 42 ISS missions provided the basis for the pre-flight, in-flight and post-flight work completed by NASA's Space Medicine Operations Division, while our Russian colleagues provided valuable insights from their long-duration mission experiences with missions lasting 10-14 months, which predated the ISS era. Space Medicine's Behavioral Health and Performance Group (BHP) provided pre-flight training, evaluation, and preparation as well as in-flight psychological support for the NASA crewmember. While the BHP team collaboratively planned for this mission with the help of all ISS international partners within the Human Behavior and Performance Working Group to leverage their collective expertise, the US and Russian BHP personnel were responsible for their respective crewmembers. The presentation will summarize the lessons and experience gained within the areas identified by this Working Group as being of primary importance for a one-year mission.

Beven, G.↗
NASA NTRS2016

Astronaut Clothing for Exploration Missions

Astronaut clothes for exploration missions beyond low Earth orbit need to satisfy several challenges not met by the currently-used mostly-cotton clothing. A laundering system is not expected to be available, and thus soiled garments must be trashed. Jettisoning waste does not seem feasible at this time. The cabin oxygen concentration is expected to be higher than standard, and thus fabrics must better resist ignition and burning. Fabrics need to be identified that reduce logistical mass, that can be worn longer before disposal, that are at least as comfortable as cotton, and that resist ignition or that char immediately after ignition. Human factors and psychology indicate that crew well-being and morale require a variety of colors and styles to accommodate personal identity and preferences. Over the past four years, the Logistics Reduction Project under NASA's Advanced Exploration Systems Program has sponsored the Advanced Clothing System Task to conduct several ground studies and one ISS study. These studies have evaluated length of wear and personal preferences of commercially-available exercise- and routine-wear garments made from several fabrics (cotton, polyester, Merino wool, and modacrylic), woven and knitted. Note that Merino wool and modacrylic char like cotton in ambient air, while polyester unacceptably melts. This paper focuses on the two components of an International Space Station study, onboard and on the ground, with astronauts and cosmonauts. Fabrics were randomized to participants. Length of wear was assessed by statistical survival analysis, and preference by exact binomial confidence limits. Merino wool and modacrylic t-shirts were worn longer on average than polyester t-shirts. Interestingly, self-assessed preferences were inconsistent with length-of-wear behavior, as polyester was preferred to Merino wool and modacrylic.

Poritz, Darwin H.↗
NASA NTRS2016

Sweat Rates During Continuous and Interval Aerobic Exercise: Implications for NASA Multipurpose Crew Vehicle (MPCV) Missions

Aerobic deconditioning is one of the effects spaceflight. Impaired crewmember performance due to loss of aerobic conditioning is one of the risks identified for mitigation by the NASA Human Research Program. Missions longer than 8 days will involve exercise countermeasures including those aimed at preventing the loss of aerobic capacity. The NASA Multipurpose Crew Vehicle (MPCV) will be NASA's centerpiece architecture for human space exploration beyond low Earth orbit. Aerobic exercise within the small habitable volume of the MPCV is expected to challenge the ability of the environmental control systems, especially in terms of moisture control. Exercising humans contribute moisture to the environment by increased respiratory rate (exhaling air at 100% humidity) and sweat. Current acceptable values are based on theoretical models that rely on an "average" crew member working continuously at 75% of their aerobic capacity (Human Systems Integration Requirements Document). Evidence suggests that high intensity interval exercise for much shorter durations are equally effective or better in building and maintaining aerobic capacity. This investigation will examine sweat and respiratory rates for operationally relevant continuous and interval aerobic exercise protocols using a variety of different individuals. The results will directly inform what types of aerobic exercise countermeasures will be feasible to prescribe for crewmembers aboard the MPCV.

Ryder, Jeffrey W.↗
NASA NTRS2016

Effects of Acute Exposures to Carbon Dioxide Upon Cognitive Functions

Large quantities of carbon dioxide (CO2) originate from human metabolism and typically, within spacecraft, remain about 10-fold higher in concentration than at the earth's surface. There have been recurring complaints by crew members of episodes of "mental viscosity" adversely affecting their performance, and there is evidence from the International Space Station (ISS) that associates CO2 levels with reports of headaches by crewmembers. Additionally, there is concern that CO2 may contribute to vision impairment and intracranial pressure that has been observed in some crewmembers. Consequently, flight rules have been employed to control the level of CO2 below 4 mm Hg, which is well below the existing Spacecraft Maximum Allowable Concentration (SMAC) of 10 mm Hg for 24-hour exposures, and 5.3 mm Hg for exposures of 7 to 180 days. However, the flight rule imposed limit, which places additional demands upon resources and current technology, still exceeds the lower bound of the threshold range for reportable headaches (2 - 5 mm Hg). Headaches, while sometime debilitating themselves, are also symptoms that can provide evidence that physiological defense mechanisms have been breached. The causes of the headaches may elicit other subtle adverse effects that occur at CO2 levels well below that for headaches. The concern that CO2 may have effects at levels below the threshold for headaches appears to be substantiated in unexpected findings that CO2 at concentrations below 2 mm Hg substantially reduced some cognitive functions that are associated with the ability to make complex decisions in conditions that are characterized by volatility, uncertainty, complexity, ambiguity, and delayed feedback. These are conditions that could be encountered by crews in off-nominal situations or during the first missions beyond low earth orbit. If findings of the earlier study are confirmed in crew-like subjects, our findings would provide additional evidence that CO2 may need to be controlled at levels that are well below current spacecraft limits. Our study will extend the earlier study to determine if crew-like subjects are similarly effected by CO2. In addition to employing the Strategic Management Simulation tool, we will use the Cognition battery of psychometric measures that are being utilized aboard the ISS. It will be important to learn, by using Cognition, if additional cognitive domains are sensitive to concentrations of CO2 at or below limits currently controlled by flight rules. While spaceflight Cognition data will greatly enhance the knowledge base related to inflight behavioral health and performance, some of the measures may be influenced by fatigue (related to sleep deprivation and or workload) and changes in circadian rhythms. Therefore our use of this battery of tests in a well-controlled, ground-based study that is free of these potential confounding influences will establish a baseline terrestrial data set against which Cognition data collected in flight may be assessed. The findings from this study will be useful to the NASA Toxicology Office and the National Research Council Committee on Toxicology, which assists NASA in setting environmental standards, for revision of the SMAC for CO2, and for designing further studies on effects of CO2 upon cognitive functions.

Scully, R. R.↗
NASA NTRS2016

Design Status of the Capillary Brine Residual in Containment Water Recovery System

One of the goals of the AES Life Support System (LSS) Project is to achieve 98% water loop closure for long duration human exploration missions beyond low Earth orbit. To meet this objective, the AES LSS Project is developing technologies to recover water from wastewater brine; highly concentrated waste products generated from a primary water recovery system. The state of the art system used aboard the International Space Station (ISS) has the potential to recover up to 85% water from unine wastewater, leaving a significant amounts of water in the waste brine, the recovery of which is critical technology gap that must be filled in order to enable long duration human exploration. Recovering water from the urine wastewater brine is complicated by the concentration of solids as water is removed from the brine, and the concentration of the corrosive, toxic chemicals used to stabilize the urine which fouls and degrades water processing hardware, and poses a hazard to operators and crew. Brine Residual in Containment (BRIC) is focused on solids management through a process of "in-place" drying - the drying of brines within the container used for final disposal. Application of in-place drying has the potential to improve the safety and reliability of the system by reducing the exposure to curew and hardware to the problematic brine residual. Through a collaboration between the NASA Johnson Space Center and Portland Status University, a novel water recovery system was developed that utilizes containment geometry to support passive capillary flow and static phase separation allowing free surface evaporation to take place in a microgravity environment. A notional design for an ISS demonstration system was developed. This paper describes the testing performed to characterize the performance of the system as well as the status of the system level design.

Sargusingh, Miriam J.↗
NASA NTRS2015

The Ion Propulsion System for the Solar Electric Propulsion Technology Demonstration Mission

The Asteroid Redirect Robotic Mission is a candidate Solar Electric Propulsion Technology Demonstration Mission whose main objectives are to develop and demonstrate a high-power solar electric propulsion capability for the Agency and return an asteroidal mass for rendezvous and characterization in a companion human-crewed mission. The ion propulsion system must be capable of operating over an 8-year time period and processing up to 10,000 kg of xenon propellant. This high-power solar electric propulsion capability, or an extensible derivative of it, has been identified as a critical part of an affordable, beyond-low-Earth-orbit, manned-exploration architecture. Under the NASA Space Technology Mission Directorate the critical electric propulsion and solar array technologies are being developed. The ion propulsion system being co-developed by the NASA Glenn Research Center and the Jet Propulsion Laboratory for the Asteroid Redirect Vehicle is based on the NASA-developed 12.5 kW Hall Effect Rocket with Magnetic Shielding (HERMeS0 thruster and power processing technologies. This paper presents the conceptual design for the ion propulsion system, the status of the NASA in-house thruster and power processing activity, and an update on flight hardware.

Electric Propulsion↗
NASA NTRS2015

NASA Composite Cryotank Technology Project Game Changing Program

The fundamental goal of this project was to provide new and innovative cryotank technologies that enable human space exploration to destinations beyond low earth orbit such as the moon, near-earth asteroids, and Mars. The goal ... to mature technologies in preparation for potential system level flight demonstrations through significant ground-based testing and/or laboratory experimentation

Fikes, John↗