Spin about sun vector with initially set attitude

Information

 
QuestionHow can I spin my satellite about the sun vector with a unique, initially set attitude?
Answer
Please reference our help page for information on the 'spinning' attitude profile.

To further explain the 'spinning' predefined attitude type, we need to know the difference between the body axes and the inertial axes.
  • The body axes defines the initial rotation of the satellite
  • The inertial axes are referenced off the central body's inertial axes and define the vector that the satellite will rotate about.

You can set these axes with a few methods including Cartesian, spherical, Euler angles, and pitch/roll. In the following example, we are using Cartesian to set these values.

I have my 'Fixed in Axes' satellite with the body axes and sun vector enabled in the 3D Graphics window.
  1. Right-click your 'Fixed in Axes' satellite and Copy (User-added image) and paste (User-added image) it.
  2. Rename the new satellite, Spinning.
  3. Right-click your Fixed in Axes satellite and open the Report and Graph Manager (User-added image).
  4. Create a new report style and call it Sun Vector.
  5. In the Properties window, look for the Vector Choose Axes type and select the Time, x, y, and z option.
  6. Move (User-added image) them over to the right and click OK.
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Generate the Sun Vector Report

  1. Generate the Sun Vector report and when the window appears, select the 'Fixed in Axes' body frame.
  2. Generate the Sun Vector report again and this time select the 'Fixed in Axes' ICRF frame. Make sure you keep track of which report is which.

Set the Attitude Type

  1. Open 'Fixed in Axes' properties (User-added image).
  2. Select the Basic - Attitude page.
  3. Set the Type to Spinning.
  4. Set the types for Body and Inertial to Cartesian.
  5. Enter the X, Y, and Z values from the Fixed in Axes body report in the Body field.
  6. Enter the X, Y, and Z values from the Fixed in Axes ICRF report in the Inertial field.
  7. Click Apply.
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Create a New Angle in Analysis Workbench

  1. Open Analysis Workbench (User-added image).
  2. Create a new angle with the following properties. 
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Display the New Angle

  1. Select the 3D Graphics - Vector properties of the 'Spinning' satellite.
  2. Click Add and find the Fixed in Axes SpinOffset angle you just made.
  3. Enable the Show angle value option and click Apply. Make sure you are at the beginning of your scenario time. You'll see the angle value in the 3D Graphics window.
  4. Select the Basic - Attitude properties in your satellite and enter the angle value in the Spin Offset field.
  5. Click Apply and your Spinning satellite body axes now aligns with the Fixed in Axes body axes and it rotates about the sun vector as you animate.
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