Deliverables and access to the Integrated Radiation Design Tools fill identified gaps documented in the Human Research Program (HRP) Integrated Research Plan (HRP-47065, Rev. A) to support the evaluation of effective shielding options by the engineering community:

· Cancer - 11: What are the most effective shielding approaches to mitigate cancer risks?

· Cancer - 13: What are the most effective approaches to integrate radiation shielding analysis codes with collaborative engineering design environments used by spacecraft and planetary habitat design efforts?

· Acute - 6: What are the most effective shielding approaches to mitigate acute radiation risks, how do we know, and implement?

IRADT will specifically address the limitations associated with simplified geometry description (equivalent aluminum, three-layer transport interpolation, random orientation) and straight ahead transport. The design tools increases fidelity by incorporating common spacecraft and user specified materials in the geometry description with ray-by-ray transport to minimize the uncertainties due to range-scaling of material thicknesses and material ordering. Ray-by ray transport also establishes the basis to calculate the forward/backward neutron generation within vehicle/lunar surface geometries. The back-scattered neutron environment will be calculated from the opposite sides of the vehicle for a crew member’s specific orientation at specific tissue locations. This will increase our ability to evaluate the effectiveness of shielding systems. In supporting the closure of these gaps, the Design Tool Project tools and models will support specification, implementation, verification, and monitoring of Spaceflight Human Systems Standard, Vol. 2 (NASA STD 3001, Vol. 2) radiation design and operational requirements with improved uncertainty quantification.

The integrated tools and models will be supplied to the user community via a website called OLTARIS (On-Line Tool for the Assessment of Radiation in Space), which can be accessed at https://oltaris.nasa.gov .

The Matthia 2013 GCR (galactic cosmic ray) model (Matthiä, D., Berger, T., Mrigakshi A. , T., Reitz G., A Ready-to-Use Galactic Cosmic Ray Model, Adv. in Space Res. 51 (2013) pp. 329-338) was added for freespace, Earth orbit, and surface environments. The model can be defined one of three ways, by selecting an historic solar min/max, by entering specific dates, or by entering a fitting parameter. A comprehensive comparison of the various GCR models was published by Slaba, et. al. (see publications) and it showed that the Matthia model was on par with the Badhwar-O'Neill 2010 model in terms of uncertainty for space radiation calculations. The Badhwar-O'Neill 2010 and 2004 models are also still available.

The linear energy transfer (LET) response has now been activated for all geometry and project types. It was previously only available for interpolation-based, thickness distribution jobs for free-space environments. Both the integral and differential flux/fluence vs. LET is computed and the target material can be specified as either tissue or silicon.

A new atmosphere model has been added for Mars surface environments. The Mars Climate Database (MCD, http://www-mars.lmd.jussieu.fr/ ) is a database of atmospheric statistics compiled from state-of-the-art simulations of the Martian atmosphere. It is a much more refined model than MarsGRAM and takes into account the surface location (latitude and longitude), the Martian seasons (Solar longitude) and the time of day (Local solar time).

OLTARIS ( https://oltaris.nasa.gov/ ) currently has 223 active accounts, which is an increase of 53 accounts over the current reporting period. 81 accounts are government (including NASA, Oak Ridge National Laboratory, Jet Propulsion Laboratory, Air Force Research Laboratory, and Federal Aviation Administration), 86 are university professors/researchers/students, and 56 are industry (including Boeing, Space X, Lockheed-Martin, Alliant Techsystems Inc., Northrup Grumman, and Bigelow Aerospace).

There have been nearly 4000 jobs run through OLTARIS during the current reporting period and 14,500 since counting began in November 2009.

Deliverables and access to the Integrated Radiation Design Tools fills identified gaps documented in the HRP Integrated Research Plan (HRP-47065, Rev. A) to support the evaluation of effective shielding options by the engineering community:

· Cancer - 11: What are the most effective shielding approaches to mitigate cancer risks?

· Cancer - 13: What are the most effective approaches to integrate radiation shielding analysis codes with collaborative engineering design environments used by spacecraft and planetary habitat design efforts?

· Acute - 6: What are the most effective shielding approaches to mitigate acute radiation risks, how do we know, and implement?

IRADT will specifically address the limitations associated with simplified geometry description (equivalent aluminum, three-layer transport interpolation, random orientation) and straight ahead transport. The design tools increases fidelity by incorporating common spacecraft and user specified materials in the geometry description with ray-by-ray transport to minimize the uncertainties due to range-scaling of material thicknesses and material ordering. Ray-by ray transport also establishes the basis to calculate the forward/backward neutron generation within vehicle/lunar surface geometries. The back-scattered neutron environment will be calculated from the opposite sides of the vehicle for a crew member’s specific orientation at specific tissue locations. This will increase our ability to evaluate the effectiveness of shielding systems. In supporting the closure of these gaps, the Design Tool Project tools and models will support specification, implementation, verification, and monitoring of Spaceflight Human Systems Standard, Vol. 2 (NASA STD 3001, Vol. 2) radiation design and operational requirements with improved uncertainty quantification.

The integrated tools and models will be supplied to the user community via a website called OLTARIS (On-Line Tool for the Assessment of Radiation in Space), which can be accessed at https://oltaris.nasa.gov .

The capability to create a LEO environment from a user-uploaded trajectory was added. User trajectories may either be analyzed as before (by integrating the environment over the trajectory) or on a point-by-point basis. When the job is submitted as an averaged trajectories, the external environment (boundary condition) is computed at each trajectory point and integrated to obtain an average environment. The average environment is then run as a single computation to provide total response quantities (and averaged per-day rates) for the entire trajectory. When the job is submitted as a point-by-point trajectory, the external environment is computed at each trajectory point and run as a separate job. The results are then combined and returned as a function of time along the trajectory.

The capability to run ray-by-ray transport for vehicle thickness distributions was added. In this analysis, the transport is run along each ray in the thickness distribution and includes backward neutron transport (like slab calculations). This allows thickness distributions to have up to 100 different materials, in any order, along each ray.

The Badhwar-O'Neill 2010 GCR model was added for freespace, Earth orbit, and surface environments. The user can still select the older Badhwar-O'Neill 2004 as well but the site now defaults to the 2010 model.

The lunar surface environment has been updated to add the neutron albedo. Jobs that are submitted as an interpolation-based run will have the neutron albedo applied to surface-pointing rays, while the rest of the rays will receive the free-space environment. The GCR albedo is computed without the vehicle. The SPE albedo is considered negligible since the vehicle would shield the lunar surface in the 1-D transport, thus it is set to zero. In the case of ray-by-ray transport, an appropriate amount of lunar regolith is added to the surface pointing rays, which will automatically account for the neutron albedo in the bi-directional transport along each ray.

Generalized spheres can now be created and used for project geometries. These spheres are defined similarly to slabs and can contain any number of layers and materials. These jobs are run using forward-only transport and effective dose calculations use an orientation-averaged, or spinning astronaut, phantom position.

Mars surface environments (for SPE and GCR) have been added. The Mars environments can only be used with vehicle thickness distributions and are always executed using ray-by-ray transport. A surface-local-vertical vector needs to be defined to indicate which hemisphere is up and exposed to the atmosphere. The opposite hemisphere is assumed to be regolith. A Field-of-View (FOV) response has also been added for Mars surface projects to aid in comparisons to particle telescope-type instruments.

OLTARIS currently has 170 active accounts. 70 accounts are government (including NASA, ORNL, JPL, AFRL, and FAA), 54 are university professors/researchers/students, and 46 are industry (including Boeing, Space X, Lockheed-Martin, ATK, Northrup Grumman, and Bigelow Aerospace).

There have been 10,900 jobs run through OLTARIS since counting began in November 2009.

Deliverables and access to the Integrated Radiation Design Tools fills identified gaps documented in the HRP Integrated Research Plan (HRP-47065, Rev. A) to support the evaluation of effective shielding options by the engineering community:

· Cancer - 11: What are the most effective shielding approaches to mitigate cancer risks?

· Cancer - 13: What are the most effective approaches to integrate radiation shielding analysis codes with collaborative engineering design environments used by spacecraft and planetary habitat design efforts?

· Acute - 6: What are the most effective shielding approaches to mitigate acute radiation risks, how do we know, and implement?

IRADT will specifically address the limitations associated with simplified geometry description (equivalent aluminum, three-layer transport interpolation, random orientation) and straight ahead transport. The design tools increases fidelity by incorporating common spacecraft and user specified materials in the geometry description with ray-by-ray transport to minimize the uncertainties due to range-scaling of material thicknesses and material ordering. Ray-by ray transport also establishes the basis to calculate the forward/backward neutron generation within vehicle/lunar surface geometries. The back-scattered neutron environment will be calculated from the opposite sides of the vehicle for a crew member’s specific orientation at specific tissue locations. This will increase our ability to evaluate the effectiveness of shielding systems. In supporting the closure of these gaps, the Design Tool Project tools and models will support specification, implementation, verification, and monitoring of Spaceflight Human Systems Standard, Vol. 2 (NASA STD 3001, Vol. 2) radiation design and operational requirements with improved uncertainty quantification.

The integrated tools and models will be supplied to the user community via a website called OLTARIS (On-Line Tool for the Assessment of Radiation in Space), which can be accessed at https://oltaris.nasa.gov .

The Solar Particle Event (SPE) environments were updated to allow the user to define their own spectrum using a variety of fitting functions. The user can still select from historical events or define their own using the Weibull, exponential in energy, exponential in rigidity, or Band function fits. The Galactic Cosmic Ray (GCR) environments were also updated to allow the user to define an environment based on the solar modulation parameter, in addition to selecting an historic solar min/max or by entering dates. The developers are currently working on giving the user the ability to upload trajectories for Earth orbit environment, and that capability should be available in the next reporting period.

Complex geometries are evaluated by the user ray-tracing their vehicle at a specific location and then uploading the thickness distribution via an XML file. Until now, the thickness distributions were limited to three materials - aluminum, polyethylene, and tissue. This capability has been greatly enhanced by allowing the user to use any three-material combination they wish. The user first defines their material(s) via the OLTARIS materials page, then once the material cross sections have been computed, the user can reference their custom materials in the vehicle thickness distribution. This same methodology will eventually be expanded so that the user can define and use any number of materials.

The design environments for the joint NASA/ESA missions to the moons of Jupiter were added (trapped electrons, protons, and heavy ions) along with an integrated electron transport capability. The user can now select from 4 mission scenarios and evaluate dose in silicon for both complex and slab geometries.

Deliverables and access to the Integrated Radiation Design Tools fills identified gaps documented in the HRP Integrated Research Plan (HRP-47065, Rev. A) to support the evaluation of effective shielding options by the engineering community:

• Cancer - 11: What are the most effective shielding approaches to mitigate cancer risks?

• Cancer - 13: What are the most effective approaches to integrate radiation shielding analysis codes with collaborative engineering design environments used by spacecraft and planetary habitat design efforts?

• Acute - 6: What are the most effective shielding approaches to mitigate acute radiation risks, how do we know, and implement?

The design tools methods will specifically address the limitations associated with simplified geometry description (equivalent aluminum, three-layer transport interpolation, random orientation) and straight ahead transport. The design tools increases fidelity by incorporating common spacecraft and user specified materials in the geometry description with ray-by-ray transport to minimize the uncertainties due to range-scaling of material thicknesses and material ordering. Ray-by ray transport also establishes the basis to calculate the forward/backward neutron generation within vehicle/lunar surface geometries. The back-scattered neutron environment will be calculated from the opposite sides of the vehicle for a crew member’s specific orientation at specific tissue locations. This will increase our ability to evaluate the effectiveness of shielding systems. In supporting the closure of these gaps, the Design Tool Project tools and models will support specification, implementation, verification, and monitoring of Spaceflight Human Systems Standard, Vol. 2 (NASA STD 3001, Vol. 2) radiation design and operational requirements with improved uncertainty quantification.

[Ed. note: added to Task Book 5/3/2011 when received project information]