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NASA NTRS2011

Medical Updates Number 5 to the International Space Station Probability Risk Assessment (PRA) Model Using the Integrated Medical Model

The Integrated Medical Model (IMM) Project has been developing a probabilistic risk assessment tool, the IMM, to help evaluate in-flight crew health needs and impacts to the mission due to medical events. This package is a follow-up to a data package provided in June 2009. The IMM currently represents 83 medical conditions and associated ISS resources required to mitigate medical events. IMM end state forecasts relevant to the ISS PRA model include evacuation (EVAC) and loss of crew life (LOCL). The current version of the IMM provides the basis for the operational version of IMM expected in the January 2011 timeframe. The objectives of this data package are: 1. To provide a preliminary understanding of medical risk data used to update the ISS PRA Model. The IMM has had limited validation and an initial characterization of maturity has been completed using NASA STD 7009 Standard for Models and Simulation. The IMM has been internally validated by IMM personnel but has not been validated by an independent body external to the IMM Project. 2. To support a continued dialogue between the ISS PRA and IMM teams. To ensure accurate data interpretation, and that IMM output format and content meets the needs of the ISS Risk Management Office and ISS PRA Model, periodic discussions are anticipated between the risk teams. 3. To help assess the differences between the current ISS PRA and IMM medical risk forecasts of EVAC and LOCL. Follow-on activities are anticipated based on the differences between the current ISS PRA medical risk data and the latest medical risk data produced by IMM.

Butler, Doug↗

NASA NTRSDate not supplied

Guidance, Navigation, and Control for Laser-Based Non-Cooperative Target Detumbling

Orbital debris is a well known and growing problem presenting risks to the future of spaceflight. Many pieces of debris are defunct satellites or rocket upper stages. These large objects could generate an exponentially growing cloud of debris should they be involved in a collision, i.e., Kessler Syndrome. Future orbital debris remediation efforts often propose perturbing the orbit of these large targets to mitigate risk. These plans often involve non-cooperative rendezvous. In the absence of active control, the targets are expected to be tumbling which makes rendezvous a dangerous prospect. In this work we describe a guidance, navigation, and control system for a contactless non-cooperative target detumbling methodology which will significantly increase the safety of non-cooperative rendezvous. An onboard laser generates thrust on the target by ablating its surface material. This thrust is used to control target attitude. Our guidance, navigation, and control system is able to estimate relative pose, target the laser, and maintain formation flight during the detumbling process. The system is validated with Monte Carlo simulation in a variety of scenarios.

Guidance↗

NASA NTRS2002

Development of Advanced Life Cycle Costing Methods for Technology Benefit/Cost/Risk Assessment

The overall objective of this three-year grant is to provide NASA Langley's System Analysis Branch with improved affordability tools and methods based on probabilistic cost assessment techniques. In order to accomplish this objective, the Aerospace Systems Design Laboratory (ASDL) needs to pursue more detailed affordability, technology impact, and risk prediction methods and to demonstrate them on variety of advanced commercial transports. The affordability assessment, which is a cornerstone of ASDL methods, relies on the Aircraft Life Cycle Cost Analysis (ALCCA) program originally developed by NASA Ames Research Center and enhanced by ASDL. This grant proposed to improve ALCCA in support of the project objective by updating the research, design, test, and evaluation cost module, as well as the engine development cost module. Investigations into enhancements to ALCCA include improved engine development cost, process based costing, supportability cost, and system reliability with airline loss of revenue for system downtime. A probabilistic, stand-alone version of ALCCA/FLOPS will also be developed under this grant in order to capture the uncertainty involved in technology assessments. FLOPS (FLight Optimization System program) is an aircraft synthesis and sizing code developed by NASA Langley Research Center. This probabilistic version of the coupled program will be used within a Technology Impact Forecasting (TIF) method to determine what types of technologies would have to be infused in a system in order to meet customer requirements. A probabilistic analysis of the CER's (cost estimating relationships) within ALCCA will also be carried out under this contract in order to gain some insight as to the most influential costs and the impact that code fidelity could have on future RDS (Robust Design Simulation) studies.

Yackovetsky, Robert↗

NASA NTRS2024

Review of the Natural History of Renal Stones in U.S. Astronauts

BACKGROUND: The formation of renal stones in astronauts may pose a considerable threat to crew health and to the completion of mission objectives. Although a history of prior renal stones is an exclusion criterion for initial selection, there have been reported cases of renal stones that have developed after selection. This led to the establishment, nine years ago, of a standardized protocol to screen for the development of renal stones pre-and post-spaceflight in all active astronauts. OVERVIEW: Literature regarding stone makeup, size, location, time to passage, and outcomes were reviewed, as well as incidence of renal stones in astronaut analog populations such as military pilots and the general population. The Lifetime Surveillance of Astronaut Health (LSAH) database was queried and as of 2015 there have been 22 crew members who have reported 36 renal stone events from a population of 357 astronauts, with an incidence of 0.32 events per year. This compares favorably to the incidence of 0.37 to 0.46events per year in commercial pilots. DISCUSSION: The physiologic changes associated with spaceflight have been thought to present an increased risk for the development of stones, including hypercalciuria, decreased urine pH, and reduced urine volume. NASA’s screening program, based on a rigorous ultrasound method, has now provided nine years of clinical data used to reduce the risk of flying an astronaut with a renal stone that could threaten health and mission objectives. This work and data from the ultrasound screening program was used to update the clinical practice guideline for renal stone surveillance and treatment, and other NASA documents and programs that track this risk.

C McNerlin↗

NASA NTRS2018

Agile Approach to Adding Assurance and Mitigating Overall Mission Risk for Orion Software on EM-1

Human-rated missions like Orion are becoming exceedingly complex in terms of software contribution to achieving mission objectives, and this creates a resource challenge for everyone whose job is to add assurance that the mission is going to fly safely. Orion IV&V has addressed this challenge by providing focused assurance results of critical mission capabilities prioritized by a dynamic assessment of risk level. Prior to this approach, Orion IV&V was evaluating areas of risk in much broader, and more static, terms. Due to the Agile software development cycle that Orion follows, IV&V findings were often reported months out of phase with the developer. As a result of evolving the approach to providing assurance on Orion, IV&V is able to incrementally deliver high-priority assurance data and more impactful issues more in phase with the developer activities, thereby increasing the value of the findings to the project. The agile IV&V approach employed by the Orion IV&V team strives to achieve a cadence of delivery that matches the pace of development. This agile approach provides increased flexibility for the assurance provider to become more efficient in reporting assurance conclusions and issues. This presentation will discuss the principles which drive the design of our approach, results to date, and aspirations for long-term performance.

Assurance↗

NASA NTRSDate not supplied

Development of a THOR Anthropometric Test Device Lumbar Spine Injury Risk Function

Currently, the Brinkley Dynamic Response Criteria (BDRC) is used to assess the risk of thoraco-lumbar spinal injury for astronauts. The BDRC has been validated for predicting injury in military aircraft ejections (Brinkley, 1968; Brinkley and Schaffer, 1971). The objective of this study was to use the injurious data behind the BDRC and subinjurious human-volunteer data to develop an injury risk function for the Test device for Human Occupant Restraint (THOR) to predict probability of thoraco-lumbar spine injury during space vehicle landings.

Jessica Wells↗

NASA NTRS2003

Managing flight software cost risk

This paper reports on the results of a follow up study conducted on seven JPL missions completed on or near launch since 1999. The objective is to determine to what extent the recommendations were implemented and whether they had any impact.

software cost cost risk↗

NASA NTRS1976

A decision model for planetary missions

Many techniques developed for the solution of problems in economics and operations research are directly applicable to problems involving engineering trade-offs. This paper investigates the use of utility theory for decision making in planetary exploration space missions. A decision model is derived that accounts for the objectives of the mission - science - the cost of flying the mission and the risk of mission failure. A simulation methodology for obtaining the probability distribution of science value and costs as a function spacecraft and mission design is presented and an example application of the decision methodology is given for various potential alternatives in a comet Encke mission.

Hazelrigg, G. A., Jr.↗

NASA NTRS1979

Overview of the carbon fiber problem

Carbon fibers (CF) composite structures are being utilized more as alternatives to metals in both civilian and military applications. They are valued for their light weight and high strength as well as for their ease of designing structures with specific shapes and sizes. However, a problem may exist due to the high conductivity of CF. CF are manufactured from a precursor material which is subjected to great stress and heat treatment causing a change in the physical and electrical properties. The fibers are bound together by a matrix of epoxy. In the event of fire (aircraft accident) the epoxy would burn away releasing these fibers into the atmosphere. When these fibers come in contact with electronic equipment, they might cause damage to by settling on electrical junctions. An overview is given of the objectives for a study, and the approach and methodology developed for determination of risk profiles.

Source record↗

NASA NTRS1989

Microgravity sensitivities for Space Station ECLS subsystems

This report presents a review of the Space Station Environmental Control and Life Support subsystems (ECLSS) for sensitivity to low gravity environments. The object of this review is to categorize sensitivity areas and to quantify the risks. This review addresses all processes from a top level view and then examines in more detail those areas which were considered potential risks. The study has concentrated on the primary function of the subsystems which may be significant to the performance of the particular component and does not address integration of the subsystem and/or the mechanical aspects of the designs. The areas of primary concern were the Atmosphere Revitalization (AR), Water Recovery and Management (WRM), and the Waste Management (WM) subsystems.

Bangham, M. E.↗

NASA NTRS2015

Coordinated Field Campaigns in Chesapeake Bay and Gulf of Mexico

NASA's GEOstationary Coastal and Air Pollution Events (GEO-CAPE) mission concept recommended by the U.S. National Research Council (2007) focuses on measurements of atmospheric trace gases and aerosols and aquatic coastal ecology and biogeochemistry from geostationary orbit (35,786 km altitude). Two GEO-CAPE-sponsored multi-investigator ship-based field campaigns were conducted to coincide with the NASA Earth Venture Suborbital project DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaigns: (1) Chesapeake Bay in July 2011 and (2) northwestern Gulf of Mexico in September 2013. Goal: to evaluate whether GEO-CAPE coastal mission measurement and instrument requirements are optimized to address science objectives while minimizing ocean color satellite sensor complexity, size and cost - critical mission risk reduction activities. NASA continues to support science studies related to the analysis of data collected as part of these coordinated field campaigns and smaller efforts.

GoMex↗

NASA NTRS2017

Lunar Advanced Volatile Analysis Subsystem: Pressure Transducer Trade Study

In Situ Resource Utilization (ISRU) is a key factor in paving the way for the future of human space exploration. The ability to harvest resources on foreign astronomical objects to produce consumables and propellant offers potential reduction in mission cost and risk. Through previous missions, the existence of water ice at the poles of the moon has been identified, however the feasibility of water extraction for resources remains unanswered. The Resource Prospector (RP) mission is currently in development to provide ground truth, and will enable us to characterize the distribution of water at one of the lunar poles. Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) is the primary payload on RP that will be used in conjunction with a rover. RESOLVE contains multiple instruments for systematically identifying the presence of water. The main process involves the use of two systems within RESOLVE: the Oxygen Volatile Extraction Node (OVEN) and Lunar Advanced Volatile Analysis (LAVA). Within the LAVA subsystem, there are multiple calculations that depend on accurate pressure readings. One of the most important instances where pressure transducers (PT) are used is for calculating the number of moles in a gas transfer from the OVEN subsystem. As a critical component of the main process, a mixture of custom and commercial off the shelf (COTS) PTs are currently being tested in the expected operating environment to eventually down select an option for integrated testing in the LAVA engineering test unit (ETU).

Kang, Edward Shinuk↗

NASA NTRS2019

Building an Economical and Sustainable Lunar Infrastructure to Enable Human Lunar Missions

To enable return of human missions to the surface of the Moon sustainably, a new study was initiated to assess the feasibility of developing an evolvable, economical and sustainable lunar surface infrastructure using a public-private partnerships approach. This approach would establish partnerships between NASA and private industry to mutually develop lunar surface infrastructure capabilities to support robotic missions initially and later evolve to full-scale commercial infrastructure services in support of human missions. These infrastructure services may range from power systems, communication and navigation systems, thermal management systems, mobility systems, water and propellant production to life support systems for human habitats. The public-private partnerships approach for this study leverages best practices from NASA's Commercial Orbital Transportation Services (COTS) program which introduced a new innovative and economical approach for partnering with industry to develop commercial cargo transportation services to the International Space Station (ISS). In this approach, NASA and industry partners shared cost and risk throughout the development phase which led to dramatically reducing development and operations costs of these transportation services. Following this approach, a Lunar COTS concept was conceived to follow this model and gradually develop cost-effective surface infrastructure capabilities in partnership with industry to provide economical, operational services for small-scale robotic missions. To support human missions, this work has now been extended to analyze full-scale lunar infrastructure systems. This infrastructure system will have capabilities to support human missions from a few days to several months and will also maximize the use of existing lunar resources, such as, water from ice deposits at the lunar poles. The plan includes a gradual buildup of these capabilities using a phased-development approach that will eventually lead to operational infrastructure services. By partnering with industry to develop and operate the infrastructure services using the COTS model, this plan will also result in significant cost savings, reduced risk and increased reliability. This paper will describe the Lunar COTS concept goals, objectives and approach for developing an evolvable, economical and sustainable human lunar infrastructure as well as the challenges and opportunities for development.

Lunar Surface Systems↗

NASA NTRS2024

Assessing the Number of Crew for Mars Against Trade Space Parameters

Missions to Mars will differ from all previous human spaceflight missions in that the onboard crew of astronauts will be required to operate in an Earth-independent manner given the long communication delays on Mars missions. Without a systematic, repeatable process to determine the number and composition of crew necessary to successfully accomplish these missions, NASA increases the risk in that crew sizes may be too small to meet primary mission objectives under nominal conditions and, more consequentially, the crewmembers may not have the expertise needed to successfully respond to unforeseen failures without the real-time expertise in the Mission Control Central (MCC) team on which NASA has come to rely. We present a framework for trade space analysis along with results from human-performance models developed in IMPRINT. We discuss the implications of model results on the trade space for number of crew for missions to Mars. This work was funded by the NASA Engineering and Safety Center (NESC) with support from NASA’s Human Research Program (HRP).

Donna Dempsey↗

NASA NTRSDate not supplied

An Investigation Into Transecting Satellites in Future Space Traffic Management Scenarios

The number of satellites expected to populate the near-Earth space environment is set to dramatically increase in the coming decade as new large constellations are approved and deployed. Current strategies for deploying new batches of these satellites often involve launching into an initial orbit, and then performing apogee raising maneuvers to reach a target altitude. Similarly, end-of-life planning for these constellation satellites can consist of de-orbit burns that lower perigee to permit disposal via re-entry. Both the raising and de-orbiting maneuvers can result in the individual satellites traveling in transecting orbits that have the potential to cross other spacecraft trajectories. While individual large constellations may be able to coexist in separate altitude and inclination bands, having thousands of satellites moving between these bands as new satellites are added and old satellites are removed could pose additional collision risks. Similar concerns have been raised regarding the impact that large numbers of university-class CubeSats might have in terms of their overall collision risk, especially as these satellites typically do not have propulsion systems for active maneuvering. To assess the impact that transecting satellites might have on future space traffic management strategies, this study explored a variety of realistic future scenarios using a high-fidelity simulation tool. The model can simulate the orbit of tens of thousands of resident space objects (RSOs) simultaneously, to include active satellites, debris, rocket bodies, or even future hypothetical satellite constellations, using a realistic force model that incorporates non-spherical gravity, atmospheric drag, and solar radiation pressure, as well as station-keeping. The simulation can be customized to accommodate different methods of calculating the probability of collision, as well as the process for determining probability ellipsoids and screening volumes. This makes it possible to replicate, and compare, different processes used by different spacecraft operators and space situational awareness (SSA) providers. As the model is run forward in time, each conjunction event is recorded, allowing for the analysis of statistics and meta-data related to these events, providing insight into the nature and frequency of potential collisions, such as whether are they active or passive objects, what size are the two objects, and who owns the objects (if known). This information makes it possible to characterize how changes to the status quo affect the number and type of conjunctions that occur, as well as the distributional effects on various types of satellite operators. To assess the general risks that transecting satellites might pose for hypothetical future space object environments, approximately 60,000 new large constellation satellites were considered, in addition to the existing catalog of approximately 7800 known resident space objects (RSOs), over a simulation period of one year. The results indicate that the future space environment will introduce a non-linear increase in conjunction events as the number of RSOs also increase. This will require adjustments to spacecraft fuel budgets in order to conduct the avoidance maneuvers necessary to minimize collision risk, both for existing and new satellites. This increase is due in large part to the higher density of RSOs and the overlap between some constellation orbits. Current catalog objects were shown to require three times more ∆V for collision avoidance (CA) maneuvers in the simulated future environment, and some constellation spacecraft were estimated to devote the majority of their annual ∆V to CA. The impact of small satellites was found to be proportional for the current space environment, and actually decreased in terms of percentage for the future scenario, suggesting that small satellites do not pose an outsized collision risk. Lastly, transecting satellites were found to contribute thousands of additional conjunctions outside of their operational orbit, and may require up to an additional 5% in CA maneuver fuel allocation.

conjunction assessment↗

NASA NTRS1994

Single track effects, Biostack and risk assessment

The scientific career of Prof. Bucker has spanned a very exciting period in the fledgling science of Space Radiation Biology. The capability for placing biological objects in space was developed, and the methods for properly packaging, retrieving and analyzing them were worked out. Meaningful results on the effects of radiation were obtained for the first time. In fact, many of the successful techniques and methodologies for handling biological samples were developed in Prof. Bucker's laboratories, as attested by the extensive Biostack program. He was the first to suggest and successfully carry out experiments in space directly aimed at measuring effects of single tracks of high-energy heavy galactic cosmic rays by specifically identifying whether or not the object had been hit by a heavy particle track. Because the "hit" frequencies of heavy galactic cosmic rays to cell nuclei in the bodies of space travelers will be low, it is expected that any effects to humans on the cellular level will be dominated by single-track cell traversals. This includes the most important generally recognized late effect of space radiation exposure: radiation-induced cancer. This paper addresses the single-track nature of the space radiation environment, and points out the importance of single "hits" in the evaluation of radiation risk for long-term missions occurring outside the earth's magnetic field. A short review is made of biological objects found to show increased effects when "hit" by a single heavy charged-particle in space. A brief discussion is given of the most provocative results from the bacterial spore Bacillus subtilis: experimental evidence that tracks can affect biological systems at much larger distances from the trajectory than previously suspected, and that the resultant inactivation cross section in space calculated for this system is very large. When taken at face value, the implication of these results, when compared to those from experiments performed at ground-based accelerators with beams at low energies in the same LET range, is that high-energy particles can exert their influence a surprising distance from their trajectory and the inactivation cross sections are some 20 times larger than expected. Clearly, beams from high-energy heavy-ion accelerators should be used to confirm these results. For those end points that can also be caused by low-LET beams such as high-energy protons, it is important to measure their action cross sections as well. The ratio of the cross sections for a high-LET beam to that of a low-LET beam is an interesting experimental ratio and, we suggest, of more intrinsic interest than the RBE (Relative Biological Effectiveness). It is a measure of the "biological" importance of one particle type relative to another particle type. This ratio will be introduced and given the name RPPE (Relative Per Particle Effectiveness). Values of RPPE have appeared in the literature and will be discussed. A rather well-known value of this quantity (13,520) has been suggested for the RPPE of high-energy iron ions to high-energy protons. This value was suggested by Letaw et al. Nature 330, 709-710 (1987)] we will call it the Letaw limit. It will be discussed in terms of the importance of the heavy-ion component vs light-ion component of the galactic cosmic rays. It is also pointed out, however, that there may be unique effects from single tracks of heavy ions that do not occur from light-ion tracks. For such effects, the concepts of both RBE and RPPE lose their meaning.

NASA Discipline Radiation Health↗

NASA NTRSDate not supplied

NASA’s Space Sustainability Strategy: An Overview and a Conceptual Framework for Implementation

Space sustainability is crucial for the continuation of humanity's exploration and utilization of space. NASA recognizes the imperative of maintaining a sustainable space operating environment to safeguard the future of space activities. On April 9, 2024, NASA released its first part of an integrated Space Sustainability Strategy focused on the domain of earth orbit, with future volumes to address impacts of space operations on earth itself; cislunar space, including the Lagrange points and the lunar surface; and deep space, including other celestial bodies. This commitment extends to ensuring the safety of astronauts conducting operations in Low Earth Orbit (LEO), as well as enabling missions to the Moon and Mars. Moreover, sustainable space practices are essential for the uninterrupted operation of NASA's robotic science missions, which monitor Earth's changes and probe the mysteries of the universe. The strategy sets out a set of goals, the first of which is to establish a framework for assessing space sustainability at NASA, addressing the absence of a universally accepted framework with key metrics that promotes understanding of how metrics are interconnected. This framework will provide a basis for evaluating the sustainability of orbital activities, with metrics informed by input from the domestic and international space community. Objectives under this goal include defining key parameters affecting space sustainability, determining tolerable levels of risk, and annually publishing NASA's effect on space sustainability, including compliance with orbital debris mitigation standards. The subsequent goals build upon this foundation, identifying effective actions for enhancing space sustainability, incentivizing adoption of these actions through technology development and policy changes, and ensuring coordination with the global space community. An organizational change within NASA is also proposed to facilitate day-to-day coordination and accountability for space sustainability efforts. By pursuing these goals, NASA aims to strengthen the technical foundations of and continue to set an example for sustainable space operations. Regular evaluation of NASA mission performance in context with meeting sustainability objectives will ensure alignment with evolving challenges in the space operating environment.

Matt Forsbacka↗

NASA NTRS2017

Probabilistic Asteroid Impact Risk Assessment for the Hypothetical PDC17 Impact Exercise

Performing impact risk assessment for the 2017 Planetary Defense Conference (PDC17) hypothetical impact exercise, to take place at the PDC17 conference, May 15-20, 2017. Impact scenarios and trajectories are developed and provided by NASA's Near Earth Objects Office at JPL (Paul Chodas). These results represent purely hypothetical impact scenarios, and do not reflect any known asteroid threat. Risk assessment was performed using the Probabilistic Asteroid Impact Risk (PAIR) model developed by the Asteroid Threat Assessment Project (ATAP) at NASA Ames Research Center. This presentation includes sample results that may be presented or used in discussions during the various stages of the impact exercisecenter dot Some cases represent alternate scenario options that may not be used during the actual impact exercise at the PDC17 conference. Updates to these initial assessments and/or additional scenario assessments may be performed throughout the impact exercise as different scenario options unfold.

Asteroid Impact Risk↗