The STK SEET Thermal and Vehicle Temperature Model computes the mean steady-state temperature of a satellite, missile, or launch vehicle due to direct solar and reflected Earth radiation, using simple thermal balancing equations. STK SEET treats the space vehicle as a single isothermal node, where you specify bulk thermal characteristics. The temperature computations are based on models for either spherical objects, or planar objects with a specified orientation.
The three main heat sources that affect a vehicle in space are direct thermal energy from the Sun, the energy from sunlight that reflects off the Earth (albedo), and infrared energy emitted from the Earth due to its temperature. All sources contribute while the space vehicle is sunlit, but only the infrared Earthshine component contributes while it is in the shadow of the Earth. These sources of emitted and absorbed energy, along with any internal heat-dissipation, are accounted for in the space vehicle's thermal management system.
For additional background information, consult: SEET: Space Environment and Effects Tool for STK (PDF).
Options for STK SEET Thermal Model
| Option | Description |
|---|---|
| Earth Albedo |
A value between 0.1 and 0.7 representing the fraction of incident sunlight reflected by the Earth. |
| Material Emissivity | A value between zero and one representing the ratio of the total radiant energy emitted by the material relative to a blackbody at the same temperature (equal to absorptivity under thermal equilibrium). |
| Material Absorptivity |
A value between zero and one representing the fraction of the incoming radiation that is absorbed (not reflected) by the material, independent of the incident angle of the radiation with the surface. |
| Dissipation | A value between zero and 1.0e9 watts representing the heat generated by the operation of internal components of a space vehicle. |
| Cross-Sectional Area | Cross-sectional area of the shape model. For the spherical model, this value should equal Pi times the radius squared; for the plate model, this value should equal the area of the plate. |
| Shape Model | Options are:
|
| Normal Vector | Direction normal to the plate when Shape Model is Plate, specified using the Vector Geometry Tool (VGT) |