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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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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

The Probability of False Go/No-Go Determined by GOES Proton Flux: Proposed Launch Constraints for Avoiding Damaging Solar Energetic Particle Events

Most space-bound hardware needs to be designed to withstand space weather events to some degree. Long-term predictability of space weather events, such as solar flares or coronal mass ejections, are still a matter of theory so designers should assume a worst case event for their specific environment. In our analysis, we show preliminary results of the probability of encountering a false/true go/no-go based on a threshold launch and design proton environment. The goal in choosing a threshold launch environment is to avoid the chance of exceeding the design environment during vulnerable parts of the mission. Operationally, this method cannot predict damaging space weather but can aid in avoiding space weather events that are already occurring. The GOES (Geostationary Operational Environmental Satellite) proton flux database is used as a proxy for the heavy ion fluxes, which impart a greater threat because of larger single event upsets and effects. Our use of protons as a proxy for heavy ions is justified on the basis of the correlation between their fluxes shown by a qualitative comparison of GOES proton integral fluxes at greater than 10 megaelectronvolts and ACE/SIS (Advanced Composition Explorer / Solar Isotope Spectrometer) heavy ion integral fluxes.

DeStefano, Anthony M.↗
NASA NTRS2020

Space Weather Architecture Options to Support Human and Robotic Deep Space Exploration

Understanding solar energetic particle (SEP) event characteristics is critical to the proper design of human and robotic space missions. This report details a study of operational response time for monitoring space weather for crewed flights, specifically targeting lunar and Mars missions. The NESC assessment team evaluated the required minimum latency for data streams and forecasts that will directly affect mission operations using a 41-year database (i.e., European Space Agency (ESA) Solar Energetic Particle Environment Modeling (SEPEM) RSDv2.0) of SEP events. The database contained 192 SEP events that resulted in a dose increase above background levels. Of those, 10% were “multiple events,” or events that occurred in quick succession. The analysis provides probabilistic values for time to peak flux and dose rate for the duration of each event. This NESC assessment also evaluated the SEP threshold levels for exploration missions to determine the relevant energy range of required proton measurements.

Solar energetic particle↗
NASA NTRSDate not supplied

SEP Forecasting from the Lunar Gateway

The European Radiation Sensor Array (ERSA) planned to fly onboard the Gateway lunar space station will include a Standard Radiation Environment Monitor (SREM) energetic particle detector. The SREM detector has a long heritage and has flown aboard the Earth-orbiting INTEGRAL and PROBA-1 satellites, the L2 experiments Herschel and Planck, and the inner solar system mission Rosetta. SREM measures energetic protons between 11 – 250 MeV, enabling it to detect proton and electron enhancements due to solar energetic particle (SEP) events, which are potentially hazardous for humans and hardware in space. The UMASEP model, developed by Marlon Nuñez at the University of Malaga, ingests energetic particle measurements to produce forecasts of time to threshold crossing and the maximum flux expected within a certain time window. UMASEP is a mature model that has been running in real time for many years and has demonstrated forecasting skill. We plan to develop a UMASEP-Gateway >30 MeV forecast module using historical INTEGRAL/SREM data so that the model may begin forecasting as soon as ERSA begins returning real time data. UMASEP-Gateway will use the environment at the habitat to produce forecasts. This work will enable forecasting using the in situ environment at the spacecraft and will additionally act as a first step towards producing SEP forecasts directly at the vehicle where humans reside, a key capability that will be needed for exploration missions beyond the Moon.

space weather↗
NASA NTRS2012

Real Time Space Weather Support for Chandra X-ray Observatory Operations

NASA launched the Chandra X-ray Observatory in July 1999. Soon after first light in August 1999, however, degradation in the energy resolution and charge transfer efficiency of the Advanced CCD Imaging Spectrometer (ACIS) x-ray detectors was observed. The source of the degradation was quickly identified as radiation damage in the charge-transfer channel of the front-illuminated CCDs, by weakly penetrating ("soft", 100-500 keV) protons as Chandra passed through the Earth s radiation belts and ring currents. As soft protons were not considered a risk to spacecraft health before launch, the only on-board radiation monitoring system is the Electron, Proton, and Helium Instrument (EPHIN) which was included on Chandra with the primary purpose of monitoring energetic solar particle events. Further damage to the ACIS detector has been successfully mitigated through a combination of careful mission planning, autonomous on-board radiation protection, and manual intervention based upon real-time monitoring of the soft-proton environment. The AE-8 and AP-8 trapped radiation models and Chandra Radiation Models are used to schedule science operations in regions of low proton flux. EPHIN has been used as the primary autonomous in-situ radiation trigger; but, it is not sensitive to the soft protons that damage the front-illuminated CCDs. Monitoring of near-real-time space weather data sources provides critical information on the proton environment outside the Earth's magnetosphere due to solar proton events and other phenomena. The operations team uses data from the Geostationary Operational Environmental Satellites (GOES) to provide near-real-time monitoring of the proton environment; however, these data do not give a representative measure of the soft-proton (less than 1 MeV) flux in Chandra s high elliptical orbit. The only source of relevant measurements of sub-MeV protons is the Electron, Proton, and Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE) satellite at L1, with real-time data provided by NOAA's Space Weather Prediction Center. This presentation will discuss radiation mitigation against proton damage, including models and real-time data sources used to protect the ACIS detector system.

O'Dell, Stephen L.↗
NASA NTRS2012

Real Time Space Weather Support for Chandra X-Ray Observatory Operations

NASA launched the Chandra X-ray Observatory in July 1999. Soon after first light in August 1999, however, degradation in the energy resolution and charge transfer efficiency of the Advanced CCD Imaging Spectrometer (ACIS) x-ray detectors was observed. The source of the degradation was quickly identified as radiation damage in the charge-transfer channel of the front-illuminated CCDs, by weakly penetrating ( soft , 100 500 keV) protons as Chandra passed through the Earth s radiation belts and ring currents. As soft protons were not considered a risk to spacecraft health before launch, the only on-board radiation monitoring system is the Electron, Proton, and Helium Instrument (EPHIN) which was included on Chandra with the primary purpose of monitoring energetic solar particle events. Further damage to the ACIS detector has been successfully mitigated through a combination of careful mission planning, autonomous on-board radiation protection, and manual intervention based upon real-time monitoring of the soft-proton environment. The AE-8 and AP-8 trapped radiation models and Chandra Radiation Models are used to schedule science operations in regions of low proton flux. EPHIN has been used as the primary autonomous in-situ radiation trigger; but, it is not sensitive to the soft protons that damage the front-illuminated CCDs. Monitoring of near-real-time space weather data sources provides critical information on the proton environment outside the Earth s magnetosphere due to solar proton events and other phenomena. The operations team uses data from the Geostationary Operational Environmental Satellites (GOES) to provide near-real-time monitoring of the proton environment; however, these data do not give a representative measure of the soft-proton (< 1 MeV) flux in Chandra s high elliptical orbit. The only source of relevant measurements of sub-MeV protons is the Electron, Proton, and Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE) satellite at L1, with real-time data provided by NOAA s Space Weather Prediction Center. This presentation describes the radiation mitigation strategies to minimize the proton damage in the ACIS CCD detectors and the importance of real-time data sources that are used to protect the ACIS detector system from space weather events.

O'Dell, Stephen L.↗
NASA NTRSDate not supplied

The Miniaturized Electron Proton Telescope, MERiT onboard Lunar Gateway

The Lunar Gateway or the Gateway, part of NASA’s Artemis program, is a space station orbiting around the moon The cis-lunar Gateway platform provides the opportunity for Heliophysics investigations to advance our knowledge of the coupled Sun-Earth system and the opportunity better understand the radiation environment in order to support and improve crew safety and operations at the Moon and beyond. The Heliophysics Environmental and Radiation Measurement Experiment Suite (HERMES) is a suite of instruments place on the outside of the Habitation and Logistics Outpost ( HALO) monitor the Sun’s radiation environment and space weather. HERMES, led byNASA’s Goddard Space Flight Center, will monitor lower energy solar particles critical to scientific investigations of the Sun including the solar winds. Additional suite of instruments provided by ESA, the European Radiation Sensors Array (ERSA) will complement space weather studies. We report here on the energetic particle instrument, the Minaturized Electron Proton Telescope (MERiT) on board HERMES designed to measure electrons and protons in the energy range ~0.3-9. MeV and ~1-190 MeV in 11 and 20 differential energy channels respectively. MERiT is a solid state detector telescope with the two sensor heads:one looking sunward and the other anti-sunward. MERiT will help advance our understanding of solar energetic particles, low energy cosmic rays and energetic electrons in the magnetospheric tail. We will describe the instrument in details and the science topics it is expected to address. Lunar Gateway is currently expected to launch in 2024

Shri Kanekal↗
NASA NTRS2011

The Roles of Transport and Wave-Particle Interactions on Radiation Belt Dynamics

Particle fluxes in the radiation belts can vary dramatically during geomagnetic active periods. Transport and wave-particle interactions are believed to be the two main types of mechanisms that control the radiation belt dynamics. Major transport processes include substorm dipolarization and injection, radial diffusion, convection, adiabatic acceleration and deceleration, and magnetopause shadowing. Energetic electrons and ions are also subjected to pitch-angle and energy diffusion when interact with plasma waves in the radiation belts. Important wave modes include whistler mode chorus waves, plasmaspheric hiss, electromagnetic ion cyclotron waves, and magnetosonic waves. We investigate the relative roles of transport and wave associated processes in radiation belt variations. Energetic electron fluxes during several storms are simulated using our Radiation Belt Environment (RBE) model. The model includes important transport and wave processes such as substorm dipolarization in global MHD fields, chorus waves, and plasmaspheric hiss. We discuss the effects of these competing processes at different phases of the storms and validate the results by comparison with satellite and ground-based observations. Keywords: Radiation Belts, Space Weather, Wave-Particle Interaction, Storm and Substorm

Fok, Mei-Ching↗
NASA NTRS2011

Lunar Solar Origins Exploration (LunaSOX)

The Moon offers a unique vantage point from which to investigate the Sun and its interaction via the solar wind magnetic fields, plasma, and energetic particles with the geospace system including the Moon itself. The lunar surface and exosphere provide in part a record of solar coronal plasma material input and resultant space weathering over billions of years. The structure and dynamics of solar wind interactions with the Moon provide an accessible near-Earth laboratory environment for study of general solar wind interactions with the vast multitude of airless asteroidal bodies of the inner solar system. Spacecraft in lunar orbit have the often simultaneous opportunity, except when in the Earth's magnetosphere, to make in-situ compositional measurements of the solar wind plasma and to carry out remote observations from the Moon of the solar corona, potentially enabled by lunar limb occultation of the solar disk. The LunaSOX project at NASA Goddard Space Flight Center is addressing these heliophysical science objectives from and of the Moon with support from NASA's Lunar Advanced Science and Exploration Research (LASER) program: (1) specify history of solar wind parameters at and sunward of the Moon through enhanced access (http://lunasox.gsfc.nasa.gov/) to legacy and operational mission data products from the Apollo era to the present, (2) model field and plasma interactions with the lunar surface, exosphere, and wake, as constrained by the available data, through hybrid kinetic code simulations, and (3) advance mission concepts for heliophysics from and of the Moon.

Cooper, John F.↗
NASA NTRS2023

CEPS – A Compact Electron-Proton Spectrometer

Small mass/low-power sensors are needed for autonomous Moon/Mars surface ops that provide alerts to impending adverse space weather conditions. In order to use current operational forecasting tools, a sensor capable of measuring both high-energy electrons and protons is needed. By combining high-TRL Timepix technology with a CdTe layer, this project leverages known technology to fill a critical gap for surface operations. Typical space weather sensors are at least an order of magnitude higher in mass than is expected from Timepix-based devices and are deployed on robotic assets away from human crews. High fidelity measurements at the crew location and subsequent ability are needed to provide warnings to crews to shelter with a device that can easily be carried on the Lunar and Martian surfaces.​ The aim of this project is the development of compact, low power space weather sensors for crew protection based on the combination of AES flight heritage Timepix hardware with novel CdTe (Cadmium Telluride) sensors. CdTe technology has only recently matured to a point where it can be reliably used with Timepix detectors. These detectors will be able to measure electron spectra in an energy range relevant to the RELEASE model, which is used operationally by NASA to provide crew early warning of Solar Energetic Particle Events as well as protons in the energy ranges relevant to human health allowing for event ‘nowcasting’ and total event crew dose prediction. Compared to existing solutions these detectors will be compact enough to travel with crew, providing a significant advantage to space environment situation awareness. Project results indicate that CdTe-based Timepix sensors respond well to energetic electrons, and particle tracks are sufficiently distinct to be able to measure in a mixed radiation field. Detector response functions were developed for both electrons and protons. Measurement results showed response to both electrons and protons in the energy range of interest for human space flight.

Radiation↗
DOE OSTI2021

Do Impulsive Solar-Energetic-Electron (SEE) Events Drive High-Voltage Charging Events on the Nightside of the Moon?

When the Earth’s moon is in the supersonic solar wind, the darkside of the Moon and the lunar plasma wake can be very dangerous charging environments. In the absence of photoelectron emission (dark) and in the absence of cool plasma (wake), the emission or collection of charge to reduce electrical potentials is difficult. Unique extreme charging events may occur during impulsive solar-energetic-electron (SEE) events when the lunar wake is dominated by relativistic electrons, with the potential to charge and differentially charge objects on and above the lunar surface to very-high negative electrical potentials. In this report the geometry of the magnetic connections from the Sun to the lunar nightside are explored; these magnetic connections are the pathways for SEEs from the Sun. Rudimentary charging calculations for objects in the relativistic-electron environment of the lunar wake are performed. To enable these charging calculations, secondary-electron yields for impacts by relativistic electrons are derived. Needed lunar electrical-grounding precautions for SEE events are discussed. Calls are made 1) for future dynamic simulations of the plasma wake in the presence of time-varying SEE-event relativistic electrons and time-varying solar-wind magnetic-field orientations and 2) for future charging calculations in the relativistic-electron wake environment and on the darkside lunar surface.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2019

Space Radiation and Plasma Effects on Satellites and Aviation: Quantities and Metrics for Tracking Performance of Space Weather Environment Models

The Community Coordinated Modeling Center has been leading communitywide space science and space weather model validation projects for many years. These efforts have been broadened and extended via the newly launched International Forum for Space Weather Modeling Capabilities Assessment (https://ccmc.gsfc.nasa.gov/assessment/). Its objective is to track space weather models' progress and performance over time, a capability that is critically needed in space weather operations and different user communities in general. The Space Radiation and Plasma Effects Working Team of the afore mentioned International Forum works on one of the many focused evaluation topics and deals with five different subtopics (https://ccmc.gsfc.nasa.gov/assessment/topics/radiationall.php) and varieties of particle populations: Surface Charging from tens of eV to 50keV electrons and internal charging due to energetic electrons from hundreds keV to several MeVs. Single event effects from solar energetic particles and galactic cosmic rays (several MeV to TeV), total dose due to accumulation of doses from electrons (>100 keV) and protons (>1 MeV) in a broad energy range, and radiation effects from solar energetic particles and galactic cosmic rays at aviation altitudes. A unique aspect of the Space Radiation and Plasma Effects focus area is that it bridges the space environments, engineering, and user communities. The intent of the paper is to provide an overview of the current status and to suggest a guide for how to best validate space environment models for operational/engineering use, which includes selection of essential space environment and effect quantities and appropriate metrics.

Zheng, Yihua↗
NASA NTRS2023

The Living With a Star Space Environment Testbed Payload

The objectives, instrumentation, methods and data leading up to launch of the NASA Living With a Star (LWS) Space Environment Testbed (SET) payload onboard the Air Force Research Laboratory Demonstration and Science Experiments (DSX) spacecraft are described. The experiments characterize the space radiation environment and how it affects hardware performance. The payload consists of a compact space weather instrument and a carrier containing four board experiments.

Demonstration and Science Experiments (DSX)↗
NASA NTRSDate not supplied

Tools used in Space Radiation Operations

The goal of NASA's Radiation Health Program is to achieve human exploration and development of space without exceeding acceptable risk from exposure to ionizing radiation. The Space Radiation Analysis Group (SRAG) at NASA Johnson Space Center carries out this mission by following the philosophy of ALARA – As Low as Reasonably Achievable. SRAG utilizes a variety of tools to maintain awareness of space weather and to monitor the space radiation environment, both internal and external to the vehicle. SRAG develops and manages a wide variety of detectors that are located on the exterior and throughout the interior of the International Space Station and worn by crew. During Artemis I, SRAG provided detectors distributed within Orion’s interior and participated in the MARE experiment, which outfitted female phantoms with thousands of thermoluminescence detectors (TLD) and other dosimeters to better constrain the total dose accrued inside the human during a mission to the Moon. Motivated by the Artemis Exploration Class missions, SRAG and collaborators are developing forecasting capabilities for solar energetic particle (SEP) events and their biological impacts to crew. Tools that have come out of this work include the Acute Radiation Risk Tool (ARRT) and the SEP Scoreboards. This presentation will give an overview of the tools used in SRAG ops and currently under development to support our next steps in human space exploration.

space weather↗
NASA NTRS2023

Improved Space Weather Observations and Modeling for Aviation Radiation

In recent years there has been a growing interest from the aviation community for space weather radiation forecasts tailored to the needs of the aviation industry. In 2019 several space weather centers began issuing advisories for the International Civil Aviation Organization alerting users to enhancements in the radiation environment at aviation flight levels. Due to a lack of routine observations, radiation modeling is required to specify the dose rates experienced by flight crew and passengers. While mature models exist, support for key observational inputs and further modeling advancements are needed. Observational inputs required from the ground-based neutron monitor network must be financially supported for research studies and operations to ensure real-time data is available for forecast operations and actionable end user decision making. An improved understanding of the geomagnetic field is required to reduce dose rate uncertainties in regions close to the open/closed geomagnetic field boundary, important for flights such as those between the continental US and Europe which operate in this region. Airborne radiation measurements, which are crucial for model validation and improvement, are lacking, particularly during solar energetic particle events. New measurement campaigns must be carried out to ensure progress and in situ atmospheric radiation measurements made available for real-time situational awareness. Furthermore, solar energetic particle forecasting must be improved to move aviation radiation nowcasts to forecasts in order to meet customer requirements for longer lead times for planning and mitigation.

space weather↗
NASA NTRSDate not supplied

Analyzing Space Weather at Mars with MAVEN

To understand the processes driving Martian atmospheric escape to space, the MAVEN mission has been monitoring solar inputs at Mars since the spacecraft went into orbit in September 2014. MAVEN’s payload provides in situ measurements of solar wind ions and electrons, solar energetic particles, extreme ultraviolet radiation, and magnetic fields. With this comprehensive suite of instruments, the MAVEN team has monitored space weather at Mars for nearly a decade, over various parts of Solar Cycles 24 and 25. MAVEN observations have determined that space weather activity can deposit enough energy into the Martian system to enhance atmospheric escape by an order of magnitude. As the mission continues, monitoring space weather at Mars has become increasingly important to understand the Sun’s influence on the Martian environment. The MAVEN team provides regular reports of space weather activity, such as the occurrence and arrival time of coronal mass ejections as well as flare magnitude and peak times, to the Mars community when predictions suggest that a space weather-impacting event may be directed towards Mars. MAVEN provides observations of solar activity on the ‘far side’ of the Sun when Earth and Mars are near solar conjunction to augment measurements of solar observatories (e.g., SDO, STEREO, GOES, PSP, Solar Orbiter), providing a more global coverage of solar activity. Additionally, MAVEN is working closely with the Community Coordinated Modeling Center (CCMC) and the Moon to Mars (M2M) Space Weather Analysis Office, both located at NASA GSFC, to form the Mars Space Weather Collaboration. This collaboration utilizes MAVEN observations of space weather activity to facilitate model and prediction validation while creating tools that are available to the science community. These activities are in support of future human and robotic exploration as we identify needs to enhance current capabilities for analyzing space weather at Mars.

Gina A DiBraccio↗
NASA NTRS2007

Space Weather Nowcasting of Atmospheric Ionizing Radiation for Aviation Safety

There is a growing concern for the health and safety of commercial aircrew and passengers due to their exposure to ionizing radiation with high linear energy transfer (LET), particularly at high latitudes. The International Commission of Radiobiological Protection (ICRP), the EPA, and the FAA consider the crews of commercial aircraft as radiation workers. During solar energetic particle (SEP) events, radiation exposure can exceed annual limits, and the number of serious health effects is expected to be quite high if precautions are not taken. There is a need for a capability to monitor the real-time, global background radiations levels, from galactic cosmic rays (GCR), at commercial airline altitudes and to provide analytical input for airline operations decisions for altering flight paths and altitudes for the mitigation and reduction of radiation exposure levels during a SEP event. The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model is new initiative to provide a global, real-time radiation dosimetry package for archiving and assessing the biologically harmful radiation exposure levels at commercial airline altitudes. The NAIRAS model brings to bear the best available suite of Sun-Earth observations and models for simulating the atmospheric ionizing radiation environment. Observations are utilized from ground (neutron monitors), from the atmosphere (the METO analysis), and from space (NASA/ACE and NOAA/GOES). Atmospheric observations provide the overhead shielding information and the ground- and space-based observations provide boundary conditions on the GCR and SEP energy flux distributions for transport and dosimetry simulations. Dose rates are calculated using the parametric AIR (Atmospheric Ionizing Radiation) model and the physics-based HZETRN (High Charge and Energy Transport) code. Empirical models of the near-Earth radiation environment (GCR/SEP energy flux distributions and geomagnetic cut-off rigidity) are benchmarked against the physics-based CMIT (Coupled Magnetosphere- Ionosphere-Thermosphere) and SEP-trajectory models.

Mertens, Christopher J.↗
NASA NTRS2006

The Space Physics of Life: Searching for Biosignatures on Habitable Icy Worlds Affected by Space Weathering

Accessible surfaces of the most likely astrobiological habitats (Mars, Europa, Titan) in the solar system beyond Earth are exposed to various chemical and hydrologic weathering processes directly or indirectly induced by interaction with the overlying space environment. These processes can be both beneficial, through provision of chemical compounds and energy, and destructive, through chemical dissociation or burial, to detectable presence of biosignatures. Orbital, suborbital, and surface platforms carrying astrobiological instrumentation must survive, and preferably exploit, space environment interactions to reach these habitats and search for evidence of life or its precursors. Experience from Mars suggests that any detection of biosignatures must be accompanied by characterization of the local chemical environment and energy sources including irradiation by solar ultraviolet photons and energetic particles from the space environment. Orbital and suborbital surveys of surface chemistry and astrobiological potential in the context of the space environment should precede targeted in-situ measurements to maximize probability of biosignature detection through site selection. The Space Physics of Life (SPOL) investigation has recently been proposed to the NASA Astrobiology Institute and is briefly described in this presentation. SPOL is the astrobiologically relevant study of the interactions and relationships of potentially? or previously inhabited, bodies of the solar system with the surrounding environments. This requires an interdisciplinary effort in space physics, planetary science, and radiation biology. The proposed investigation addresses the search for habitable environments, chemical resources to support life, and techniques for detection of organic and inorganic signs of life in the context of the space environment.

Cooper, John F.↗
NASA NTRS2015

Solar Flare Track Exposure Ages in Regolith Particles: A Calibration for Transmission Electron Microscope Measurements

Mineral grains in lunar and asteroidal regolith samples provide a unique record of their interaction with the space environment. Space weathering effects result from multiple processes including: exposure to the solar wind, which results in ion damage and implantation effects that are preserved in the rims of grains (typically the outermost 100 nm); cosmic ray and solar flare activity, which result in track formation; and impact processes that result in the accumulation of vapor-deposited elements, impact melts and adhering grains on particle surfaces. Determining the rate at which these effects accumulate in the grains during their space exposure is critical to studies of the surface evolution of airless bodies. Solar flare energetic particles (mainly Fe-group nuclei) have a penetration depth of a few millimeters and leave a trail of ionization damage in insulating materials that is readily observable by transmission electron microscope (TEM) imaging. The density of solar flare particle tracks is used to infer the length of time an object was at or near the regolith surface (i.e., its exposure age). Track measurements by TEM methods are routine, yet track production rate calibrations have only been determined using chemical etching techniques [e.g., 1, and references therein]. We used focused ion beam-scanning electron microscope (FIB-SEM) sample preparation techniques combined with TEM imaging to determine the track density/exposure age relations for lunar rock 64455. The 64455 sample was used earlier by [2] to determine a track production rate by chemical etching of tracks in anorthite. Here, we show that combined FIB/TEM techniques provide a more accurate determination of a track production rate and also allow us to extend the calibration to solar flare tracks in olivine.

Berger, Eve L.↗