Tools / Beam and test / Radiation environment in 3D
Where does the radiation come from that your parts must survive?
The Sun, Earth's belts, the Moon, Mars and the planets with a magnetic field of their own, Mercury, Jupiter, Saturn, Uranus and Neptune, in three dimensions, with NASA's spacecraft models on their orbits and at their landing sites. Every environment of the rate tools on this site is tied to its orbit or place, to a real mission and to what reaches it.
3D16 rate-tool environments18 missionsan airliner and a car under the airmeasured maps, skylines and panoramas from the groundparticle labruns in your browser
Drag to turn, scroll or pinch to zoom. The Missions button of the view opens an orbit or a landing site; the list below does the same.About 8 MB for the scene, then 16 MB of spacecraft models.
The environments of the rate tools
The single-event rate tools of this site integrate a cross section against a spectrum. Each built-in spectrum belongs to an orbit or a place. The entries below name that orbit, a real mission as an example, and what the table holds; each opens in the view above and in the tools with that environment selected. The tables are CREME96 runs of September 2026 behind 100 mils of aluminum unless an entry says otherwise, and a design case such as the worst week carries no probability of occurrence.
Geostationary orbit
Cosmic rays at solar minimum: GEO and interplanetary
At geostationary orbit and beyond, Earth's field keeps out almost nothing: cosmic rays arrive nearly as in interplanetary space. Solar minimum is the case with the most of them, because a quiet solar wind holds fewer off.
Examples: GOES at geostationary orbit; TESS and a cruise to Mars see the same particles. In the tools (GCR_SolMin / ProGCRGEO): The table is the solar-quiet spectrum with no geomagnetic cutoff. Outer-belt electrons, which set the dose and the charging at this orbit, are not part of a single-event rate.
Under most of the belts, and far enough from the poles that Earth's field keeps out the slower cosmic rays. Trapped protons are met in the South Atlantic Anomaly.
Example: the International Space Station. The tool's run is for 400 km; the station flies between about 400 and 420 km. In the tools (ISS / ProISS): Cosmic rays through the quiet-time geomagnetic transmission of this orbit, and AP8MIN protons with them in the proton table.
The same orbit during a geomagnetic storm, when the disturbed field lets particles in at lower latitudes. In the tool's tables the heavy-ion flux above LET 3 MeV cm²/mg is about 1.4 times the quiet one.
Example: the International Space Station during a storm. The tool recommends this case as the conservative bound for low-inclination orbits too. In the tools (ISS_STORMY / ProISSStormy): The CREME96 stormy (disturbed) geomagnetic transmission in place of the quiet one; everything else as in the quiet case.
At 28.5 degrees the orbit never reaches high magnetic latitudes, so the cutoff stays high and the quiet-time table holds no heavy ions above LET 20 MeV cm²/mg. The South Atlantic Anomaly is still crossed several times a day.
Example: the Hubble Space Telescope, at 28.5 degrees and about 570 km (ESA fact sheet). 28.5 degrees is the latitude of Cape Canaveral. In the tools (LEO_LOW / ProLEOLow): The missing flux above LET 20 is an effect of the quiet-time cutoff, not of the part; the tool points to the stormy station case as a conservative bound.
Much like the station's orbit, a little higher and a little more inclined. The height matters: the protons of the anomaly grow quickly with altitude, to roughly four times the station's proton rate in the tool's own tables.
Example: the first Starlink shell, about 550 km at 53 degrees (eoPortal). In the tools (LEO_CONST / ProLEOConst): Cosmic rays through the quiet-time transmission of this orbit, AP8MIN protons in the proton table.
Near-polar: every turn crosses both polar caps, where the cutoff falls to almost nothing, and the horns of the outer belt. The anomaly is crossed on some turns.
Example: Landsat 8, shown here, flies a similar orbit about 100 km higher (705 km, 98.2 degrees). In the tools (SSO / ProSSO): Cosmic rays through the quiet-time transmission of this orbit, AP8MIN protons in the proton table. Solar protons reach the polar part of the orbit during an event; the tool has them as separate cases.
Twice as high as the sun-synchronous case and nearly over the poles. At 1,200 km the orbit reaches into the lower edge of the inner belt, so trapped protons are met well outside the anomaly: more than ten times the proton rate of the 600 km case in the tool's tables.
Example: the OneWeb constellation, at about 1,200 km in near-polar planes (eoPortal). In the tools (POLAR / ProPolar): Cosmic rays through the quiet-time transmission of this orbit, AP8MIN protons in the proton table.
In the outer electron belt, far above the protons of the inner belt. Cosmic rays arrive almost unhindered; the electrons set the dose and the charging of insulators.
Example: the GPS satellites, in six planes at 55 degrees and about 20,200 km, one turn in 12 hours (NASA). In the tools (MEO_NAV / ProMEONav): Cosmic rays at solar minimum through the quiet-time transmission of this orbit, with the small AP8MIN contribution in the proton table. Outer-belt electrons are not part of a single-event rate.
From 200 km to geostationary height and back in about ten and a half hours, through the inner proton belt and the outer electron belt on every turn.
Example: the transfer orbit of a geostationary satellite launched from Cape Canaveral. The Van Allen Probes, shown here, flew a similar path (about 600 by 30,600 km at 10 degrees). In the tools (GTO / ProGTO): Cosmic rays averaged over the orbit, and the AP8MIN protons of the inner-belt crossings in the proton table.
No field and no air: cosmic rays as in interplanetary space, from the half of the sky the Moon does not cover.
Examples: the Apollo landers; the Artemis surface systems. In the tools (LUNAR_SURF): The interplanetary solar-minimum spectrum behind 100 mils of aluminum, halved for the half of the sky the ground covers. Secondaries from the ground are not in it.
No global field, but air: about 20 g/cm² of carbon dioxide overhead, and the ground covering the lower half of the sky.
Examples: Curiosity, Perseverance and the other landers of this page. In the tools (MARS_SURF): The interplanetary solar-minimum spectrum through 2,700 mils of aluminum (18.5 g/cm²) standing for the air, halved for the ground. By the Bethe ranges of this page that aluminum stops the same protons as 16.2 g/cm² of carbon dioxide, less than the 20 to 22.5 g/cm² of the air here, which stop protons like 22.8 to 25.6 g/cm² of aluminum: the aluminum passes protons above about 142 MeV where the air passes them above 160 to 172 MeV, and it is thinner against nuclear collisions as well, so it generally lets more primaries through than the air does. Secondaries made in the air and the ground are not in it.
The CREME96 worst week: the flux averaged over the 180 hours from 13:00 UT on 19 October 1989, at geostationary orbit, on top of the cosmic rays. It is a design case and carries no probability of occurrence.
Example: what a GOES satellite measured in October 1989. In the tools (WorstWeek / ProFlareGEO): Used for the events expected over one whole solar particle event. Inside the magnetosphere the field keeps part of it out; the tool's tables are for geostationary orbit.
The CREME96 worst day: the flux averaged over the 18 hours from 13:00 UT on 20 October 1989, the largest enhancement of that month, when an interplanetary shock passed. A design case with no probability of occurrence.
Example: what a GOES satellite measured on 20 October 1989. In the tools (WorstDay / ProFlareWDGEO): Used where the rate during the peak of an event matters, for example for error correction and availability.
The CREME96 peak flux: the highest five-minute average that GOES saw in October 1989. Heavy ions could not be measured that fast and are scaled from the worst day. A design case with no probability of occurrence.
Example: the peak of the October 1989 events at geostationary orbit. In the tools (Peak5min / ProFlareP5): Used for the highest rate a system must ride through.
Composite mission: cosmic rays with worst-week events
A mission at geostationary orbit or beyond, as the two latchup tools count it: cosmic rays at solar minimum all the time and, on top of them, a chosen number of worst-week solar events a year, each lasting seven days.
Example: a geostationary satellite over several years; GOES is the craft shown. In the tools (COMPOSITE): The two tables are not mixed into one spectrum. The rate is averaged over the mission, R = R(cosmic rays) + R(worst week) × 7 days × events per year / 365.25, which keeps the expected number of events exact, since Poisson exposures add. It is in the SEL test-LET tool and the proton proxy tool only.
Well inside the lower edge of the inner belt: trapped protons on every turn, far more than at the height of the station.
No example is named: the table is a legacy one of the proton tools. In the tools (Pro1470): An AP-8 table kept as delivered; it was not part of the CREME96 reruns of September 2026.
Each mission is told in six short chapters: where it flies, what arrives there, what the magnetic field or the air keeps out, what passes the walls, what happens in a part, and what that means for the system.
Cosmic rays do not stop at the edge of space. In the air a cosmic ray starts a shower, and what reaches an aircraft or the ground is what the shower leaves: above all neutrons, which generally set the rate of soft errors in electronics there. The view tells both in the same six chapters, with the air as the gate and one shower drawn in it; its Spectra panel gives the neutrons by energy at the place, beside the reference of JEDEC for New York City.
Computed in the page: orbits as two-body ellipses; the places of the planets from mean elements; the cruise of Europa Clipper as three two-body arcs between its flybys, which is not the navigated trajectory; the vertical geomagnetic cutoff in a tilted dipole along each Earth orbit, and the cutoff of a dipole of Jupiter's strength along the orbit drawn there; in the views of Mercury, Jupiter, Saturn, Uranus and Neptune the drift and the bounce of trapped particles in each planet's dipole with its published tilt and offset, the cutoff in that dipole, the magnetopause and the bow shock for the pressure of the wind, and the turning of the planet and of its moons; particle speed and rigidity; the slowing of the chosen proton or iron nucleus by the Bethe formula, layer by layer through the air, the structure and the package of the part, and its LET in silicon on arrival; the chance of a nuclear collision on the way, from a stated mean free path; the charge that LET frees in a made-up part, and whether it passes the critical charge; a Hamming code. In the Spectra drawer of a mission, the flux of cosmic-ray nuclei above each LET in silicon: the nuclei from hydrogen to nickel of the ISO 15390 model as modified at DLR (Matthiä et al. 2013), through the cutoff along the orbit, the air of Mars and two layers of aluminum, where they are slowed, lost in nuclear collisions and replaced in part by the lighter nuclei that those collisions leave; cosmic rays only, and no rate. Measured data in the picture: the maps of Earth, the Moon and Mars, the AP-8 proton map of the South Atlantic Anomaly, the AE-8 profile of the outer belt, the skylines of the landing sites from the laser altimeters, the panoramas that Perseverance, Curiosity, Spirit and the crew of Apollo 17 took on the spot (Jezero crater, sol 3; Mount Sharp, sol 3481; the Columbia Hills, sols 814 to 932; the landing site at Taurus-Littrow), the cosmic-ray proton spectrum of AMS-02 and, for the two Voyagers, published fits to the interstellar spectra of protons, helium, carbon and oxygen beyond the heliopause (Bisschoff et al. 2019) with the points Voyager 1 measured there (Cummings et al. 2016). For the airliner and the car: the column of air above (US Standard Atmosphere 1976), the vertical cutoff from a map, and the neutrons, protons, muons, electrons, positrons and photons of the air showers at the place by energy, from PARMA 4 of the Japan Atomic Energy Agency (Sato 2015, 2016), an analytical model fitted to computed air showers; the page carries the parameters of that model under the terms of JAEA for non-commercial use.
Shown, not computed: the number, the paths and the timing of the particles; the secondary that can be followed in the walls scene, and the particle drawn in a scene that the chosen one did not reach, both marked as demonstrations; the brightness of the belts, and at Jupiter, Saturn, Uranus and Neptune the evenly spread dots that mark the shells on which belts were measured or to which the belt models reach, which are no map of flux; the hours at which Mercury's electron belt, which comes and goes, is drawn; where each moon of these planets is on its orbit; the shape of the boundaries of Uranus and Neptune; the shapes of the boundaries of the heliosphere and the directions of the two Voyagers; the relief and the stones near a lander, which are drawn by published size laws and are not a map of the place; in the panoramas, the ground where the rover itself stood in the picture, which is copied in from elsewhere in the same picture, and the hill behind the place of the real lunar module, which was taken out of the lunar panorama. No dose, no event rate and no effect of shielding follows from these pictures. A rate generally takes the spectrum at the part and the measured response of the part, which is what the tools are for. The shower in the air scene of the airliner and the car is drawn by rule and is no result; the street, the cloud and the sea of those two entries are scenery. In a mission the tracks beside the craft are illustrations too, but how many of a kind are drawn follows the place: cosmic rays by the share of the measured proton spectrum (AMS-02) above the cutoff, trapped particles in a low orbit by the AP-8 and AE-8 maps of the main scene at 420 km; that is a share of the tracks and no flux, and the flashes where a track meets the craft are no count of hits. The bright tracers of Earth's belts circle their field lines with the circle enlarged (7 times for a proton of 30 MeV, 70 times for an electron of 1 MeV) and with far fewer turns than in nature.
The sources of each number are named in the view itself, under Orbits, sources and model credits, and behind Show the physics in each scene.
Models, maps and credits
Spacecraft models: NASA 3D Resources and NASA Science, reduced in detail for this page. Four craft that the rate tools name as examples of an orbit (Hubble, Starlink, OneWeb, GPS III) are simplified drawings made for this page; they are not NASA models, and the view says so. Planet maps and elevation: NASA (Blue Marble, the CGI Moon Kit of the Scientific Visualization Studio, the Mars Orbiter Laser Altimeter, and the 3D models of Mercury, Venus, Jupiter, Saturn, Uranus and Europa). Their use does not imply endorsement by NASA. The credit of each model and each data set is given in the view where it is used. The airliner and the car are drawn for this page from simple solids and are the model of no make.
