Ionizing Radiation from the South Atlantic Anomaly (SAA) Using STK SEET

Problem Statement

Space Environment and Effects Tool (SEET), STK Professional, and Coverage.

Satellite designers and mission planners need to be able to quantify the amount of exposure to high levels of ionizing radiation over the course of satellite missions. The data can be used to minimize exposure and to design adequate shielding in order to prevent single event upsets and failures of sensitive instrumentation. The SAA (South Atlantic Anomaly) feature of STK SEET supports this need by computing entry and exit times and duration of exposure to selectable levels of ionizing radiation emanating from the South Atlantic Anomaly.

The results of the tutorial may vary depending on the user settings and data enabled (online operations, terrain server, dynamic Earth data, etc.). It is acceptable to have different results.

Break It Down

The following information should be determined before developing a Vehicle Temperature model scenario using STK:

  • Note the altitudes covered by the SAA database range from 400-1700 kilometers. Orbits outside this range will have limited exposure to ionizing radiation originating from the South Atlantic Anomaly.
  • You will design an orbit with a semi-major axis of 7000 km.
  • You will do a historical study from Jul 1 2016 - Jul 2 2016.
  • Select one of four proton energy channels to be analyzed (23, 38, 66, or 94 MeV), based on the nature and sensitivity of on-board instrumentation and anticipated duration of exposure.

Solution

For a given vehicle configuration and orbit, determine the amount of exposure to high levels of ionizing proton radiation over the course of its mission lifetime due to satellite interaction with the SAA. Generate a report to show this data.

Create a Scenario

  1. Create a new scenario by using the New Scenario Wizard. You can also extend the File menu and select New...
  2. Rename your scenario SEET_SSA.
  3. Set the analysis period to the following:
    OptionValue
    Analysis Start Time01 Jul 2016 16:00:00.000 UTCG
    Analysis End Time02 Jul 2016 16:00:00.000 UTCG

Add a Satellite

Add a satellite that will traverse the South Atlantic Anomaly region in altitude, as well as, latitude and longitude.

  1. Insert a new satellite using the following method:
    2. Option Value
    Select an Object to be Inserted: Satellite
    Select a Method Orbit Wizard
  2. Click the Insert button.
  3. Set the following options in the Orbit Wizard.
    4. Option Value
    Name SAA_Leo
    Type Orbit Designer
    Semi-major axis 7000 km
    Eccentricity 0.03
    Argument of Perigee 0.0
    Inclination 75 degrees
    RAAN 100 deg
    True Anomaly 0.0
  4. Click OK.
  5. Close the STK Insert Objects tool.

Set the South Atlantic Anomaly

  1. Open SAA_Leo's () properties ().
  2. Select the Basic - SEET Environment page.
  3. Locate the South Atlantic Anomaly panel.
  4. Leave the default setting of >23MeV.
  5. Set the Flux Level to Tenth of Peak.
  6. Click Apply.

View the SAA Flux Contours at a Selectable Altitude

  1. Select the 2D Graphics - SEET Environment.
  2. Enable the Show 2D and Show 3D options in the South Atlantic Anomaly Contour field.
  3. Enable the Fill option.
  4. Enable the Show At Vehicle Altitude option.
  5. Click OK.

Animate the Scenario

  1. Play () the scenario. You will see the satellite crossing the SAA. You will also notice that the contours change with the satellite altitude.
  2. Reset () the scenario when finished.

Create a Report Detailing SAA-induced Ionizing Radiation Exposure

  1. Open the Report & Graph Manager ().
  2. Click the New Report () button.
  3. Enter a name for the report like SAA_IonRadiation.
  4. Double-click the SEET SAA Crossing Times Data Provider. This will move all of those contents to Report Contents field of the report.
  5. Click OK.
  6. Generate the SAA_IonRadiation report.

Report and Analysis

A report window will be displayed containing the data selected for the report. Examine the report to determine the amount of exposure to proton radiation over the time interval of interest.

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