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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 NTRS1977

Ride quality research techniques: Section on general techniques

Information is gathered about the methods currently used for the study of ride quality in a variety of transportation modes by a variety of research organizations, including universities, Federal agencies, contracting firms, and private industries. Detailed descriptions of these techniques and their strengths and weaknesses, and identifying the organizations using such methods are presented. The specific efforts of the Group's participants, as well as a variety of feasible approaches not currently in use, are presented as methodological alternatives under the three basic factors which must be considered in ride quality studies: research techniques, research environments, and choice of subjects.

Source record↗
NASA NTRS1985

Intraplate deformation due to continental collisions: A numerical study of deformation in a thin viscous sheet

A model of crustal deformation from continental collision that involves the penetration of a rigid punch into a deformable sheet is investigated. A linear viscous flow law is used to compute the magnitude and rate of change of crustal thickness, the velocity of mass points, strain rates and their principal axes, modes of deformation, areal changes, and stress. In general, a free lateral boundary reduces the magnitude of changes in crustal thickening by allowing material to more readily escape the advancing punch. The shearing that occurs diagonally in front of the punch terminates in compression or extension depending on whether the lateral boundary is fixed or free. When the ratio of the diameter of the punch to that of the sheet exceeds one-third, the deformation is insenstive to the choice of lateral boundary conditions. When the punch is rigid with sharply defined edges, deformation is concentrated near the punch corners. With non-rigid punches, shearing results in deformation being concentrated near the center of the punch. Variations with respect to linearity and nonlinearity of flow are discussed.

Cohen, S. C.↗
NASA NTRS1990

Simulation of on-orbit modal tests of large space structures

This paper describes a procedure to analytically simulate a modal test of an on-orbit large space structure (LSS), extract the modal properties, and evaluate the success of the modal test. This procedure addresses some of the major challenges to performing an on-orbit modal test of an LSS including high modal density, low frequency modes, and limitations in excitation capabilities. A finite element model of the orbiting structure is used to predict acceleration responses due to thruster excitations, time-domain modal extraction methods are used to estimate the modal properties, and comparison of frequencies and cross-orthogonality values is used to evaluate the success of the modal test. Several alternative excitation patterns and sensor arrangements were evaluated using a space station model as an example. Results of the simulations indicate that the choice of excitation functions is critical to the success of the test.

Blelloch, Paul↗
NASA NTRS1998

Helioseismic Constraints on New Solar Models from the MoSEC Code

Evolutionary solar models are computed using a new stellar evolution code, MOSEC (Modular Stellar Evolution Code). This code has been designed with carefully controlled truncation errors in order to achieve a precision which reflects the increasingly accurate determination of solar interior structure by helioseismology. A series of models is constructed to investigate the effects of the choice of equation of state (OPAL or MHD-E, the latter being a version of the MHD equation of state recalculated by the author), the inclusion of helium and heavy-element settling and diffusion, and the inclusion of a simple model of mixing associated with the solar tachocline. The neutrino flux predictions are discussed, while the sound speed of the computed models is compared to that of the sun via the latest inversion of SOI-NMI p-mode frequency data. The comparison between models calculated with the OPAL and MHD-E equations of state is particularly interesting because the MHD-E equation of state includes relativistic effects for the electrons, whereas neither MHD nor OPAL do. This has a significant effect on the sound speed of the computed model, worsening the agreement with the solar sound speed. Using the OPAL equation of state and including the settling and diffusion of helium and heavy elements produces agreement in sound speed with the helioseismic results to within about +.-0.2%; the inclusion of mixing slightly improves the agreement.

Elliott, J. R.↗
NASA NTRS2004

IPv6 Test Bed for Testing Aeronautical Applications

Aviation industries in United States and in Europe are undergoing a major paradigm shift in the introduction of new network technologies. In the US, NASA is also actively investigating the feasibility of IPv6 based networks for the aviation needs of the United States. In Europe, the Eurocontrol lead, Internet Protocol for Aviation Exchange (iPAX) Working Group is actively investigating the various ways of migrating the aviation authorities backbone infrastructure from X.25 based networks to an IPv6 based network. For the last 15 years, the global aviation community has pursued the development and implementation of an industry-specific set of communications standards known as the Aeronautical Telecommunications Network (ATN). These standards are now beginning to affect the emerging military Global Air Traffic Management (GATM) community as well as the commercial air transport community. Efforts are continuing to gain a full understanding of the differences and similarities between ATN and Internet architectures as related to Communications, Navigation, and Surveillance (CNS) infrastructure choices. This research paper describes the implementation of the IPv6 test bed at NASA GRC, and Computer Networks & Software, Inc. and these two test beds are interface to Eurocontrol over the IPv4 Internet. This research work looks into the possibility of providing QoS performance for Aviation application in an IPv6 network as is provided in an ATN based network. The test bed consists of three autonomous systems. The autonomous system represents CNS domain, NASA domain and a EUROCONTROL domain. The primary mode of connection between CNS IPv6 testbed and NASA and EUROCONTROL IPv6 testbed is initially a set of IPv6 over IPv4 tunnels. The aviation application under test (CPDLC) consists of two processes running on different IPv6 enabled machines.

Wilkins, Ryan↗
NASA NTRS2008

Compact Two-Dimensional Spectrometer Optics

The figure is a simplified depiction of a proposed spectrometer optical unit that would be suitable for incorporation into a remote-sensing instrumentation system. Relative to prior spectrometer optical assemblies, this unit would be compact and simple, largely by virtue of its predominantly two-dimensional character. The proposed unit would be a combination of two optical components. One component would be an arrayed-waveguide grating (AWG) an integrated-optics device, developed for use in wavelength multiplexing in telecommunications. The other component would be a diffraction grating superimposed on part of the AWG. The function of an AWG is conceptually simple. Input light propagates along a single-mode optical waveguide to a point where it is split to propagate along some number (N) of side-by-side waveguides. The lengths of the optical paths along these waveguides differ such that, considering the paths in a sequence proceeding across the array of waveguides, the path length increases linearly. These waveguides launch quasi-free-space waves into a planar waveguide-coupling region. The waves propagate through this region to interfere onto an array of output waveguides. Through proper choice of key design parameters (waveguide lengths, size and shape of the waveguide coupling region, and lateral distances between waveguides), one can cause the input light to be channeled into wavelength bins nominally corresponding to the output waveguides.

Hong, John↗
NASA NTRS2006

Platform for Testing Robotic Vehicles on Simulated Terrain

The variable terrain tilt platform (VTTP) is a means of providing simulated terrain for mobility testing of engineering models of the Mars Exploration Rovers. The VTTP could also be used for testing the ability of other robotic land vehicles (and small vehicles in general) to move across terrain under diverse conditions of slope and surface texture, and in the presence of obstacles of various sizes and shapes. The VTTP consists mostly of a 16-ft-(4.88-m)-square tilt table. The tilt can be adjusted to any angle between 0 (horizontal) and 25 . The test surface of the table can be left bare; can be covered with hard, high-friction material; or can be covered with sand, gravel, and/or other ground-simulating material or combination of materials to a thickness of as much as 6 in. (approx. 15 cm). Models of rocks, trenches, and other obstacles can be placed on the simulated terrain. For example, for one of the Mars- Rover tests, a high-friction mat was attached to the platform, then a 6-in.- ( 15 cm) deep layer of dry, loose beach sand was deposited on the mat. The choice of these two driving surface materials was meant to bound the range of variability of terrain that the rover was expected to encounter on the Martian surface. At each of the different angles at which tests were performed, for some of the tests, rocklike concrete obstacles ranging in height from 10 to 25 cm were placed in the path of the rover (see figure). The development of the VTTP was accompanied by development of a methodology of testing to characterize the performance and modes of failure of a vehicle under test. In addition to variations in slope, ground material, and obstacles, testing typically includes driving up-slope, down-slope, cross-slope, and at intermediate angles relative to slope. Testing includes recording of drive-motor currents, wheel speeds, articulation of suspension mechanisms, and the actual path of the vehicle over the simulated terrain. The collected data can be used to compute curves that summarize torque, speed, power-demand, and slip characteristics of wheels during the traverse.

Lindemann, Randel↗
NASA NTRS1982

Meteorological effects on laser propagation for power transmission

An examination of possible laser operating parameters for power transmission to earth from solar power satellites is presented, with particular attention paid to assuring optimal delivery at midlatitudes. The degradation of beam efficiency due to molecular scattering, molecular absorption, aerosol scattering, and aerosol absorption during beam propagation through the atmosphere can be alleviated by judicious choice of wavelength windows, elevating the receptor sites, using a vertical propagation path, or by hole boring, i.e., vaporizing the aerosol particles in the beam path. Analyses are given for the beam propagation through fog, haze, clouds, and snow using various transitions. Only weapons-quality lasers are seen as being capable of boring through clouds and aerosols, employing a CW beam with superimposed pulses at high power densities. It is concluded that further short wavelength transmission experiments be performed to demonstrate transmission feasibility with the CW/pulsed mode of beam propagation.

Beverly, R. E., III↗
NASA NTRS2012

A Comparison of Filter-based Approaches for Model-based Prognostics

Model-based prognostics approaches use domain knowledge about a system and its failure modes through the use of physics-based models. Model-based prognosis is generally divided into two sequential problems: a joint state-parameter estimation problem, in which, using the model, the health of a system or component is determined based on the observations; and a prediction problem, in which, using the model, the stateparameter distribution is simulated forward in time to compute end of life and remaining useful life. The first problem is typically solved through the use of a state observer, or filter. The choice of filter depends on the assumptions that may be made about the system, and on the desired algorithm performance. In this paper, we review three separate filters for the solution to the first problem: the Daum filter, an exact nonlinear filter; the unscented Kalman filter, which approximates nonlinearities through the use of a deterministic sampling method known as the unscented transform; and the particle filter, which approximates the state distribution using a finite set of discrete, weighted samples, called particles. Using a centrifugal pump as a case study, we conduct a number of simulation-based experiments investigating the performance of the different algorithms as applied to prognostics.

prognostics↗
NASA NTRS1986

Non-existence of dynamical perturbations of Schwarzschild with vanishing self-dual part

A recent proposal of Ashtekar (1985) for the canonical quantisation of gravity involves a new choice of a (complex) polarisation on the (real) phase space of general relativity. In order for the 'four dimensional' version of Ashtekar's proposal to be viable, it is necessary that for an arbitrary (real) background solution there exist a sufficient number of (complex) solutions of the linearised Einstein equation with perturbed Weyl spinor having vanishing self-dual part. It is shown that this is not the case by explicitly demonstrating that for the Schwarzschild spacetime, aside from stationary perturbations, there are no such linearised solutions which can be expressed as superpositions of modes of real frequencies. The viability of the '3+1 version' of Ashtekar's proposal is not affected by these considerations.

Wald, R. M.↗
NASA NTRS2005

Effects of Control Mode and R-Ratio on the Fatigue Behavior of a Metal Matrix Composite

Composite Because of their high specific stiffness and strength at elevated temperatures, continuously reinforced metal matrix composites (MMC's) are under consideration for a future generation of aeropropulsion systems. Since components in aeropropulsion systems experience substantial cyclic thermal and mechanical loads, the fatigue behavior of MMC's is of great interest. Almost without exception, previous investigations of the fatigue behavior of MMC's have been conducted in a tension-tension, load-controlled mode. This has been due to the fact that available material is typically less than 2.5-mm thick and, therefore, unable to withstand high compressive loads without buckling. Since one possible use of MMC's is in aircraft skins, this type of testing mode may be appropriate. However, unlike aircraft skins, most engine components are thick. In addition, the transient thermal gradients experienced in an aircraft engine will impose tension-compression loading on engine components, requiring designers to understand how the MMC will behave under fully reversed loading conditions. The increased thickness of the MMC may also affect the fatigue life. Traditionally, low-cycle fatigue (LCF) tests on MMC's have been performed in load control. For monolithic alloys, low-cycle fatigue tests are more typically performed in strain control. Two reasons justify this choice: (1) the critical volume from which cracks initiate and grow is generally small and elastically constrained by the larger surrounding volume of material, and (2) load-controlled, low-cycle fatigue tests of monolithics invariably lead to unconstrained ratcheting and localized necking--an undesired material response because the failure mechanism is far more severe than, and unrelated to, the fatigue mechanism being studied. It is unknown if this is the proper approach to composite testing. However, there is a lack of strain-controlled data on which to base any decisions. Consequently, this study addresses the isothermal, LCF behavior of a [0]_32 MMC tested under strain- and load-controlled conditions for both zero-tension and tension-compression loading conditions. These tests were run at 427 C on thick specimens of SiC-reinforced Ti-15-3. For the fully-reversed tests, no difference was observed in the lives between the load- and strain-controlled tests. However, for the zero-tension tests, the strain-controlled tests had longer lives by a factor of 3 in comparison to the load-controlled tests. This was due to the fact that under strain-control the specimens cyclically softened, reducing the cracking potential. In contrast, the load-controlled tests ratcheted toward larger tensile strains leading to an eventual overload of the fibers. Fatigue tests revealed that specimens tested under fully-reversed conditions had lives approximately an order of magnitude longer than for those specimens tested under zero tension. When examined on a strain-range basis, the fully reversed specimens had similar, but still shorter lives than those of the unreinforced matrix material. However, the composite had a strain limitation at short lives because of the limited strain capacity of the brittle ceramic fiber. The composite also suffered at very high lives because of the lack of an apparent fatigue limit in comparison to the unreinforced matrix. The value of adding fibers to the matrix is apparent when the fatigue lives are plotted as a function of stress range. Here, the composite is far superior to the unreinforced matrix because of the additional load-carrying capacity of the fibers.

Source record↗
NASA NTRS2021

Strategies for the Design and Operation of Resilient Extraterrestrial Habitats

An Earth-independent permanent extraterrestrial habitat system must function as intended under continuous disruptive conditions, and with significantly limited Earth support and extended uncrewed periods. Designing for the demands that extreme environments such as wild temperature fluctuations, galactic cosmic rays, destructive dust, meteoroid impacts (direct or indirect), vibrations, and solar particle events, will place on long-term deep space habitats represents one of the greatest challenges in this endeavor. This context necessitates that we establish the know-how and technologies to build habitat systems that are resilient. Resilience is not simply robustness or redundancy: it is a system property that accounts for both anticipated and unanticipated disruptions via the design choices and maintenance processes and adapts to them in operation. We currently lack the frameworks and technologies needed to achieve a high level of resilience in a habitat system. The Resilient ExtraTerrestrial Habitats Institute (RETHi) has the mission of leveraging existing novel technologies to provide situational awareness and autonomy to enable the design of habitats that are able to adapt, absorb and rapidly recover from expected and unexpected disruptions. We are establishing both fully virtual and coupled physical-virtual simulation capabilities that will enable us to explore a wide range of potential deep space SmartHab configurations and operating modes.

Space habitats↗
NASA NTRS2021

Strategies for the Design and Operation of Resilient Extraterrestrial Habitats

An Earth-independent permanent extraterrestrial habitat system must function as intended under continuous disruptive conditions, and with significantly limited Earth support and extended uncrewed periods. Designing for the demands that extreme environments such as wild temperature fluctuations, galactic cosmic rays, destructive dust, meteoroid impacts (direct or indirect), vibrations, and solar particle events, will place on long-term deep space habitats represents one of the greatest challenges in this endeavor. This context necessitates that we establish the know-how and technologies to build habitat systems that are resilient. Resilience is not simply robustness or redundancy: it is a system property that accounts for both anticipated and unanticipated disruptions via the design choices and maintenance processes, and adapts to them in operation. We currently lack the frameworks and technologies needed to achieve a high level of resilience in a habitat system. The Resilient Extra Terrestrial Habitats Institute (RETHi) has the mission of leveraging existing novel technologies to provide situational awareness and autonomy to enable the design of habitats that are able to adapt, absorb and rapidly recover from expected and unexpected disruptions. We are establishing both fully virtual and coupled physical-virtual simulation capabilities that will enable us to explore a wide range of potential deep space Smart Hab configurations and operating modes.

Space habitats↗
NASA NTRS1997

Moving-Base Simulation Evaluation of Control/Display Integration Issues for ASTOVL Aircraft

A moving-base simulation has been conducted on the Vertical Motion Simulator at Ames Research Center using a model of an advanced, short takeoff and vertical landing (STOVL) lift fan fighter aircraft. This experiment expanded on investigations during previous simulations with this STOVL configuration with the objective of evaluating (1) control law modifications over the low speed flight envelope, (2) integration of the throttle inceptor with flight control laws that provide direct thrust command for conventional flight, vertical and short takeoff, and flightpath or vertical velocity command for transition, hover, and vertical landing, (3) control mode blending for pitch, roll, yaw, and flightpath control during transition from wing-borne to jet-borne flight, and (4) effects of conformal versus nonconformal presentation of flightpath and pursuit guidance symbology on the out-the-window display for low speed STOVL operations. Assessments were made for takeoff, transition, hover, and landing, including precision hover and landing aboard an LPH-type amphibious assault ship in the presence of winds and rough seas. Results yielded Level 1 pilot ratings for the flightpath and vertical velocity command modes for a range of land-based and shipboard operation and were consistent with previous experience with earlier control laws and displays for this STOVL concept. Control mode blending was performed over speed ranges in accord with the pilot's tasks and with the change of the basic aircraft's characteristics between wing-borne and hover flight. Blending of yaw control from heading command in hover to sideslip command in wing-borne flight performed over a broad speed range helped reduce yaw transients during acceleration through the low speed regime. Although the pilots appreciated conformality of flightpath and guidance symbols with the external scene during the approach, increased sensitivity of the symbols for lateral path tracking elevated the pilots' control activity in the presence of turbulence. The pilots preferred the choice of scaling that was originally established during the display development and in-flight evaluations.

Franklin, James A.↗
NASA NTRS2006

Few-Mode Whispering-Gallery-Mode Resonators

Whispering-gallery-mode (WGM) optical resonators of a type now under development are designed to support few well-defined waveguide modes. In the simplest case, a resonator of this type would support one equatorial family of WGMs; in a more complex case, such a resonator would be made to support two, three, or some other specified finite number of modes. Such a resonator can be made of almost any transparent material commonly used in optics. The nature of the supported modes does not depend on which material is used, and the geometrical dispersion of this resonator is much smaller than that of a typical prior WGM resonator. Moreover, in principle, many such resonators could be fabricated as integral parts of a single chip. Basically, a resonator of this type consists of a rod, made of a suitable transparent material, from which protrudes a thin circumferential belt of the same material. The belt is integral with the rest of the rod (see figure) and acts as a circumferential waveguide. If the depth (d) and width (w) of the belt are made appropriately small, then the belt acts as though it were the core of a single-mode optical fiber: the belt and its adjacent supporting rod material support a single, circumferentially propagating mode or family of modes. It has been shown theoretically that the fiber-optic-like behavior of the belton- rod resonator structure can be summarized, in part, by the difference, Dn, between (1) an effective index of refraction of an imaginary fiber core and (2) the index of refraction (n) of the transparent rod/belt material. It has also been shown theoretically that for a given required value of Dn, the required depth of the belt can be estimated as d R Dn, where R is the radius of the rod. It must be emphasized that this estimated depth is independent of n and, hence, is independent of the choice of rod material. As in the cases of prior WGM resonators, input/output optical coupling involves utilization of evanescent fields. In the present case, there are two evanescent fields: one at the belt/air interface and one in the boundary region between the belt and the rest of the rod.

Savchenkov, Anatoliy↗
NASA NTRS2009

The Need for Technology Maturity of Any Advanced Capability to Achieve Better Life Cycle Cost (LCC)

Programs such as space transportation systems are developed and deployed only rarely, and they have long development schedules and large development and life cycle costs (LCC). They have not historically had their LCC predicted well and have only had an effort to control the DDT&E phase of the programs. One of the factors driving the predictability, and thus control, of the LCC of a program is the maturity of the technologies incorporated in the program. If the technologies incorporated are less mature (as measured by their Technology Readiness Level - TRL), then the LCC not only increases but the degree of increase is difficult to predict. Consequently, new programs avoid incorporating technologies unless they are quite mature, generally TRL greater than or equal to 7 (system prototype demonstrated in a space environment) to allow better predictability of the DDT&E phase costs unless there is no alternative. On the other hand, technology development programs rarely develop technologies beyond TRL 6 (system/subsystem model or prototype demonstrated in a relevant environment). Currently the lack of development funds beyond TRL 6 and the major funding required for full scale development leave little or no funding available to prototype TRL 6 concepts so that hardware would be in the ready mode for safe, reliable and cost effective incorporation. The net effect is that each new program either incorporates little new technology or has longer development schedules and costs, and higher LCC, than planned. This paper presents methods to ensure that advanced technologies are incorporated into future programs while providing a greater accuracy of predicting their LCC. One method is having a dedicated organization to develop X-series vehicles or separate prototypes carried on other vehicles. The question of whether such an organization should be independent of NASA and/or have an independent funding source is discussed. Other methods are also discussed. How to make the choice of which technologies to pursue to the prototype level is also discussed since, to achieve better LCC, first the selection of the appropriate technologies.

Robinson, John W.↗
NASA NTRS2008

Hand-Held Units for Short-Range Wireless Biotelemetry

Special-purpose hand-held radiotransceiver units have been proposed as means of short-range radio powering and interrogation of surgically implanted microelectromechanical sensors and actuators. These units are based partly on the same principles as those of the units described in "Printed Multi- Turn Loop Antennas for RF Biotelemetry" (LEW-17879-1), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 48. Like the previously reported units, these units would make it unnecessary to have wire connections between the implanted devices and the external equipment used to activate and interrogate them. Like a unit of the previously reported type, a unit of the type now proposed would include a printed-circuit antenna on a dielectric substrate. The antenna circuitry would include integrated surface-mount inductors for impedance tuning. Circuits for processing the signals transmitted and received by the antenna would be included on the substrate. During operation, the unit would be positioned near (but not in electrical contact with) a human subject, in proximity to a microelectromechanical sensor or actuator that has been surgically implanted in the subject. It has been demonstrated that significant electromagnetic coupling with an implanted device could be established at a distance of as much as 4 in. (.10 cm). During operation in the interrogation mode, the antenna of the unit would receive a radio telemetry signal transmitted by the surgically implanted device. The antenna substrate would have dimensions of approximately 3.25 by 3.75 inches (approximately 8.3 by 9.5 cm). The substrate would have a thickness of the order of 30 mils (of the order of a somewhat less than a millimeter). The substrate would be made of low-radiofrequency- loss dielectric material that could be, for example, fused quartz, alumina, or any of a number of commercially available radio-frequency dielectric composite materials. The antenna conductors would typically be made of copper or a combination of chromium and gold. The choice of metal and the thickness of the metal layer(s) would depend on the choice of substrate material. For example, on a quartz or alumina substrate, one would typically use a layer of chromium 150 A thick and a layer of gold 2 m thick. The proposed units and the implanted devices that they would interrogate or activate would be inherently safe to use. They would operate at low radiated-power levels for short interrogation times (typically, milliseconds). Hence, there would be little local heating of tissues surrounding the implanted devices and little absorption of radio energy by such sensitive body parts as the eyes and the brain. Because the implanted devices would not depend on battery power and would be activated only during short interrogation intervals and would otherwise be in the goff h state most of the time, the useful lifetimes of the implanted devices would be greater than those of comparable battery-powered implanted devices. The compactness of the hand-held transceiver units would facilitate transport and storage and would facilitate self-diagnosis by patients able to handle the units while away from medical facilities.

Miranda, Felix A.↗
NASA NTRSDate not supplied

Evaluation of the Recent Improvements of the Nowcast of Aerospace Ionizing Radiation System (NAIRAS)

The Nowcast of Aerospace Ionizing Radiation System (NAIRAS) model is a real-time, global, physics-based model used to assess radiation exposure now running in real-time and in run on request (RoR) mode at NASA Goddard’s Community Coordinated Modeling Center. NAIRAS was recently updated to extend the galactic cosmic ray (GCR) model to include ultra-heavy nuclei (Z=29-92, A=64-238) for single event effects assessment from high linear energy transfer processes, to expand the geomagnetic cutoff rigidity model to use the either the TS05 (Tsyganenko and Sitnov, 2005), T89 (Tsyganenko, 1989), or the International Geomagnetic Reference Field model (IGRF) magnetic field models, and to improve the solar energetic particle (SEP) proton spectral fitting to better represent relativist protons during ground level enhancements. Here, we evaluate the recent NAIRAS improvements for a range of conditions. First, we demonstrate the effect of choice in magnetic field model to the NAIRAS computed dosimetric quantities for a United States domestic flight and a transatlantic flight during the May 11, 2024 SEP event. Second, the effect of ultra-heavy ions on SEP dose rate is examined for two different flight trajectories during the top SEP events. Lastly, the effect of ultra-heavy ions on NAIRAS computed GCR dose rates at solar minimum and maximum is demonstrated.

Daniel B Phoenix↗