STK SEETSpace Environment
and Effects Tool (SEET)
evaluates the effects ofthe space environment
on spacecraft.
Spacecraft designers, analysts, andoperators rely on SEET to calculate
spacecraft exposure to ionizing particles,
thermal radiation, and space debris
throughout the orbit, which is especiallycritically due to higher levels of manmade debris and increasingly energetic
natural phenomena, such as the sun’ssolar flare activities.

Key components
SEET’s functionality is provided by six
key components consisting of scientificmodels of the space environment. Thesecomponents are seamlessly integrated
into the STK user interface.
• Trapped radiation environment• South Atlantic Anomaly (SAA)• Untrapped radiation environment• Particle impacts• Vehicle temperature• Magnetic field

Trapped radiation environment
Information on vehicle dosing and incident
energetic particle flux is important because
devices on satellites degrade over time dueto the total collected dose as well as theinstantaneous dose rate.
•	Computes expected dose rate and total
dose due to energetic particle fluxes for ashielding thickness and materials.
•	Computes the energetic proton and/orelectron fluxes.
•	Computes for a specified space vehicle asa function of time or for a specified set of
spatial coordinates.
•	Choose from AFRL CRRES or NASAstandard models, or allow SEET to selectthe best model for the specific orbit.

South Atlantic Anomaly(SAA) component

passengers, as well as degraded HF
radio communications.

SAA radiation can damage spacecraft
electronics and cause Single Event Upsets(SEU), which can impair the functioning ofelectronic components.

•	Computes probabilistic fluences overmission lifetimes.

•	Computes entrance and exit times throughSAA. SAA Transit component computes
the energy flux and/or flux contour of SEU
relative probability for altitudes between
400 and 1500 km.
•	SAA model is based on data from theCompact Environment Anomaly Sensor(CEASE) detector.

Untrapped radiation environment
component
Galactic Cosmic Ray (GCR). GCRs can leadto a variety of satellite anomalies, especiallysingle event effects (SEE).
•	Computes differential and integral fluxes
and fluences.
•	Provides three different options for GCR
models: CREME86, ISO-15390, andBadhwar-O’Neill 2010.
Solar Energetic Particle (SEP). SEPs cancause problems similar to GCR, as well asother effects including increased ionizing
dose. SEPs also cause other disruptions
to technology, such as increased radiationdose to astronauts and airline crews and•	Provides three different options for SEP
models: JPL-91, Rosenqvist, and Emissionof Solar Protons (ESP).

Particle impacts component
Define or select from lists of surface
materials and properties that may bedamaged by high-velocity impact withmeteors and orbital debris.
•	Computes the total mass distribution ofmeteor and orbital debris particles that
impact a spacecraft along its orbit during a
specified time period.
•	Computes the mass distribution of theseparticles above a user-specified satellite
surface damage threshold.
•	The particle impacts algorithms are
based on AF-GEOSpace meteor anddebris models.

Vehicle temperature component
For vehicle sub-system design andoperations, thermal environment energy
combined with any internal heat dissipation
requirements must be considered.
•	Computes the mean temperature of aspace vehicle, due to direct solar flux,
reflected and infrared Earth radiation, and162110

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the dissipation of internally-generated heat
energy using thermal balancing equations.
•	Specify spherical objects or planar objects
with particular orientation, and material
emissivity and absorptivity.

Magnetic field component

SEET environment graphics

SEET constraints•	SEET can display magnetic-field contour
lines for a satellite, missile, or launchvehicle in both the 2D map and 3D globe.

STK SEET constraints enable you to
impose access constraints on a satellite,
missile, or launch vehicle based on theeffects of the space environment. You canalso opt to exclude time intervals thatsatisfy a given constraint.

•	SEET can also display contours of theSouth Atlantic Anomaly (SAA) in 2D and3D graphics windows.

SEET uses a highly customizable set of
conditions to compute the local magnetic
field at the current location. Information
about the local magnetic field at the satellite
is useful because these measurements canhelp give information about vehicle attitude.
•	Computes total magnitude along thevehicle path or on a specified set of
spatial coordinates using a chosen
magnetic field model.
•	Computes field-line tracing for display andmagnetic conjugacy.
•	Computes dipole L, McIlwain L, and B/Beq (ratio of magnetic field strength
at the current location to that at themagnetic equator).
•	Provides common magnetic field
functionality with current AF-GEOSpace
magnetic field models, including simply
tilted dipole models based on timeinterpolated moments of the full IGRF field
representation, full time-interpolated IGRF,
and full IGRF plus Olson-Pfitzer (1977)
external field models.

Specialized report andgraph optionsNumerous customizable reports and graphs
are available. Dynamic displays and strip
charts containing SEET calculations canbe displayed in real time as STK animates
through a scenario.

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