Space Radiation Features

Personal computer modeling tool for estimating ionizing radiation environments on any orbit, and computing shielding effects, single event error rates and total dose in spacecraft systems. This edition includes the AP-8 and AE-8 trapped particle models, the JPL1991 solar proton model, an improved version of the CREME galactic and solar heavy ion models, and comprehensive help files.

List of Features

Shell Shielding Distributions

Evaluate the shielding distributions anywhere inside a spherical shell, cylindrical shell, or box. These can be used in all transport calculations. Combine with dose-depth functions to compute dose inside complex geometries.

Environment Grids

Compute latitude and longitude grids of fundamental radiation environment data. Includes magnetic field intensity and components, deviation, dip angle, L-shell parameter, magnetic cutoff, trapped proton, and trapped electron grids.

Heavy-Ion SEU Test Data Fitter (HITFIT)

Automatically fit heavy-ion test data to find the sensitive volume dimensions, funnel length, LET threshold, and Weibull parameters.


The original solar proton fluence model.

Dose-Depth Functions

Compute dose vs. aluminum shielding depth curves for trapped protons, trapped electrons, and solar protons. Combine these curves with a shielding distribution to obtain the dose inside a complex geometry.

Solar Cell Damage Equivalents

Compute the 1-MeV electron equivalents for silicon and gallium arsenide solar cells using trapped proton, solar proton, and trapped electron environments. Follows the methods prescribed in the JPL Green and Blue Books.

Instant Graphics

Display high-quality plots of all Space Radiation files (except Environment Grids). Zoom in on any area of the plot. Show orbits in 3d with fast rotational capability. All output can be printed in color or B/W, copied to the clipboard, or written in EPS format.

Heavy-Ion SEU

Standard heavy-ion SEU models. Input options include empirical (LET threshold and cross section), model (critical charge and sensitive volume dimensions), Weibull parameters, and file (measured cross section vs. LET data

Extreme Solar Proton Models

Includes several models of the most intense solar proton events including August 1972 and October 1989. Models include both peak flux and total fluence for most events.


Adds batch queue, database transfer, automated file update, and lost file recovery to Space Radiation.

Environment Paths

Compute trapped proton, trapped electron, magnetic field, L value, or cutoff at each point on any orbit. The Path Analysis tells what fraction of the mission the points fall within any bounds.

Enhanced Heavy Ion Functions

Required gateway to the new heavy ion models. Includes original CREME and SPACERAD heavy ion models, transport directly to energy spectrum or LET spectrum, and transport through shielding layers.

Solar Heavy Ions (MACREE)

MACREE model of the October 1989 solar particle event developed by Boeing for the International Space Station. These new 99% worst-case solar model replace older models in the Standard Edition.

Solid Shielding Distributions

Evaluate the shielding distributions of an infinite slab, or anywhere inside a solid sphere, cylinder, or box. These can be used in all transport calculations. Combine with dose-depth functions to compute dose inside complex geometries.

Proton Spectrum Import

Import trapped proton or solar proton spectra from other sources, for example the CRRESPRO software, into Space Radiation.

Electron Spectrum Import and Models

Import any electron spectrum from other software into Space Radiation, for example, CRRESELE. Includes the fission electron spectrum model.

Neutron Spectrum Import and Models

Import any neutron spectrum from other software into Space Radiation. Includes a number of sample neutron spectra from reactors, research sources, and weapons.

Atmospheric Neutrons (Avionics/SE)

Includes the atmospheric neutron spectrum model from Avionics/SE. Allows integration along any trajectory in mean or worst-case environments.

Neutron-Induced SEU

Standard neutron-induced SEU models. Input options include LET threshold and saturation cross section, Weibull parameters, and cross section file.

Proton-Induced SEU

Standard proton-induced SEU models. Input options include one- and two-parameter Bendel (A&B) model, Weibull parameters, and cross section file.

Solar Heavy Ions (CHIME)

CHIME models of the March and June 1991 solar particle events developed by Lockheed-Martin from CRRES mission results. These new 90% worst-case solar models replace older models in the Standard Edition.

Exact Geomagnetic Shielding

This feature incorporates all known physics into an accurate calculation of the geomagnetic shielding at a point or along an orbit. It is a breakthrough in radiation effects modeling. Using it you will obtain, for the first time, the correct shielding of galactic cosmic radiation and solar particles in your spacecraft orbit. All orbits will be affected and this feature will be of special interest for computing radiation effects in highly elliptical, geostationary and high inclination orbits.

Proton-Induced SEU II

This feature computes our best guess of the proton-induced SEU rate in space using the heavy-ion test data: LET threshold and upset cross section. It is based on a Monte Carlo model utilizing fundamental nuclear cross section data. All secondary species are incorporated into the result. This feature is best suited for rapid screening of parts to determine if they are likely to be a problem or need additional testing.

Charged Particle Trajectories

Follow the trajectories of electrons, protons and heavy ions of any energy. Display the results using Instant Graphics. Use this feature to visualize how particles are arriving at your spacecraft. You can see the various features of ionizing particles in Earth’s magnetic field including South Atlantic Anomaly, geomagnetic cutoff, east-west effect, Störmer cones, electron horns, offset dipole, and mirroring.

Complex Box Shielding

This model allows you to compute dose and error rates inside a box inside a spacecraft. The box top, sides, and bottom thickness can be specified independently. The spacecraft is idealized as a large spherical shell. This is a realistic simulation of the usual system container and allows you to explore modified shielding configurations, including adding mass to one side of a container and repositioning a part within a box.

Multiple-Bit SEU

This feature uses Edmonds’ (JPL) model to estimate the probability that a single heavy ion will pass through two bits in a device causing two or more simultaneous errors. These errors dominate in systems with error correction when bits are not separated onto different devices. Inputs are the same as Heavy-Ion SEU with the addition of the bit separation distance.