Trapped radiation environment
The SEET trapped radiation environment component computes the expected dose rate and total dose due to energetic particle fluxes for a range of shielding thicknesses and materials. It can also compute the energetic proton and/or electron fluxes for a wide range of particle energies. These quantities are computed for a specified satellite orbit as a function of time or for a specified set of spatial of coordinates. Information on satellite dosing and incident energetic particle flux is important to satellite designers and mission planners because devices on satellites degrade over time due to the total collected dose as well as the instantaneous dose rate, both of which depend on the incident energetic particle flux. SEET allows the user to choose from AFRL CRRES or NASA standard models, or the user can allow SEET to select the best model for the specific orbit.
South Atlantic Anomaly (SAA)
SEET can compute a spacecraft's entrance and exit times through the SAA. The SAA is a region of space with an enhanced concentration of ionizing radiation due to the configuration of the Earth's magnetic field. Such radiation can damage spacecraft electronics and cause Single Event Upsets (SEU), which can impair the functioning of electronic components. The SAA Transit component also computes the energy flux and/or flux contour of SEU relative probability for altitudes between 400 and 1500 km. The model of the SAA is based on data received from the Compact Environment Anomaly Sensor (CEASE) detector flown on the Tri-Service Experiment (TSX-5) satellite during the epoch 2000 - 2006.
Untrapped radiation environment
SEET models the untrapped radiation environment by computing Galactic Cosmic Ray (GCR) differential and integral fluxes and fluences and Solar Energetic Particle (SEP) probabilistic fluences over mission lifetimes. Galactic Cosmic Rays (GCRs) can lead to a variety of satellite anomalies, especially single event effects (SEE) which can upset electronic components and software on the satellite. Solar energetic particles (SEPs) can cause similar problems, as well as other effects including increased ionizing dose, leading to long-term failure of electronic components, and damage to solar arrays, leading to loss of power to satellites. SEPs also cause other disruptions to technology such as increased radiation dose to astronauts and airline crews and passengers, as well as degraded HF radio communications. SEET provides three different options for GCR models: CREME86, ISO-15390, and Badhwar-O’Neill 2010 and three different options for SEP models: JPL-91. Rosenqvist, and Emission of Solar Protons (ESP).
SEET uses a highly customizable set of conditions to compute the local magnetic field at your satellite. The Magnetic Field component provides the total magnitude along the user-specified satellite path using a user-specified or default magnetic field model. This magnetic field data can also be computed on a specified set of spatial coordinates. Field line tracing for display and magnetic conjugacy computation is also provided. Information about the local magnetic field at the satellite is useful for satellite designers, mission planners, and operators because the local radiation (energetic particle) environment is organized by the magnetic field, and sometimes the local field direction as measured on the satellite can give information about the satellite attitude. This component provides common magnetic field functionality with current AF-GEOSpace magnetic field models, including simple, tilted and offset dipole models based on time-interpolated moments of the full IGRF field representation, full time-interpolated IGRF, and full IGRF plus Olson-Pfitzer (1977) external field models. The component can also compute dipole L, McIlwain L, and B/B0 (ratio of magnetic field strength at the current location to that at the magnetic equator) at the specified input coordinates.
The Particle Impacts component computes the total mass distribution of meteor and orbital debris particles that impact a spacecraft along its orbit during a specified time period. It can also compute the mass distribution of these particles above a user-specified satellite surface damage threshold. The impact of meteors and orbital debris can cause significant damage to space vehicles due to their high velocities. SEET users can define or select from lists of surface materials and properties, and custom-design meteor storms to build worst-case scenarios. The particle impacts algorithms are based on AF-GEOSpace meteor and debris models.
For satellite subsystem design and operations, thermal environment energy combined with any internal heat dissipation requirements must be considered. SEET determines the mean temperature of a spacecraft due to direct solar flux, Earth albedo and long-wave radiation, and internal energy dissipation using thermal balancing equations. A range of values for the Earth albedo and infrared radiation are supplied. The user may specify planar or spherical objects with particular orientation for the computation of temperature.
Specialized report and graph options
Numerous customizable reports and graphs are available. Dynamic displays and strip charts containing SEET calculations can be displayed in real time as STK animates through a scenario.