Orbital radiation analysis

Estimated time to complete: 15–20 minutes

In this tutorial, you will estimate the temperatures on the simplified model of a nanosatellite. Nanosatellites have masses between 1 to 10 kg. This tutorial presents the Simcenter 3D Space Systems Thermal solver environment.

1: Open the Simulation file

  1. On your desktop or the appropriate network drive, create a folder named nanosat.

  2. Click the link below:

    Download the part

  3. Extract the part files to your nanosat folder.

  4. Start Simcenter 3D or NX.

File

  • Open

  • Look in

    nanosat

  • Files of Type

    Simulation Files (*.sim)

  • Name

    nanosat_sim.sim

  • OK

     
2: Reset dialog box memory

The options you select in dialog boxes are preserved for the next time you open the same dialog box within a given session. Restore the default settings to ensure that the dialog boxes are in the expected initial state for each step of the activity.

File

Preferences→User Interface

  • Options

  •   Reset Dialog Memory

  • OK

     
3: Explore the FEM and Simulation files

Simulation Navigator

  • nanosat_fem.fem

  • 2D Collectors (hide)

  • Static Wireframe (Top Border bar→Rendering Style Drop-down list)

Simulation Navigator

  • 0D collectors

  • bus instrument

  • Information

Note:

The bus instruments are represented with a 1.5 kg mass made of aluminum.

  • Information window

  • Shaded with Edges (Top Border bar→Rendering Style Drop-down list)

Simulation Navigator

  • 2D Collectors

  • solar cells (show)

  • solar cells

  • Information

Tip:

The cells are modeled using a multi-layer shell. You can view the stack sequence and composition of each layer by accessing the Modeling Objects Manager in the FEM file.

  • Information window

Note:

Take a moment to observe the properties of the other collectors.

Simulation Navigator

  • Simulation Object Container

  • walls instruments htc tc (show)

  • walls instruments htc tc

  • Edit

Note:

This thermal coupling connects all walls to the 0D element (concentrated mass).

  • Cancel

     
4: Define the orbit of the nanosatellite

Analyze the model during the season with the lowest solar heat flux, under an orbit and satellite attitude with the following characteristics:

  • Sun synchronous orbit at a minimum altitude of 500 km.

  • Local time at ascending node 6 pm.

  • The sensors pointing to Earth (nadir).

  • Orbital Heating (Loads and Conditions group→ Simulation Object Type list)

  • Type

    Illuminate Selected Elements

  •  

  • Name

    LEO 500km 6pm

  •  

  • Region Illuminated on Top Side

  • Type Filter (Top Border bar)

    Polygon Face

  • Drag a box to select all faces.

  • Create Modeling Object

  • Planet

    Earth

  • Orbit Type

    Sun-synchronous

  • Spacecraft Attitude

  •  

  • Specify Vector

    XC-axis

  • Aim at

    Nadir

  • Specify Vector

    –YC-axis

  • Align with

    Velocity Vector

  • Sun Planet Characteristics

  •  

  • Sun Position

    June Solstice

  • Solar Flux

    W/m2

  • Compute

     

  • Orbit Parameters

  • Specify

    Minimum Altitude

  • Minimum Altitude

    500 km

  • Specify

    Eccentricity

  • Eccentricity

    0

  • Orbit Inclination

    97.4

  • Satellite Position

    Local Time at Ascending Node

  • Local Time at Ascending Node

    18:00:00

  • OK

     

  • Element Subdivision

    2

  • Display

     

  • OK

     

Options (Orbit Visualizer window→File Operations toolbar)

  •   Calculation Positions

  • Dismiss

     

  • + mouse move (rotate)

  • Shift

      + + mouse move (pan)

  • CTRL

      + + mouse move or (zoom)

  • Orbit Visualizer window

  • OK

     
5: Solve the model

The model should solve under 10 minutes. You are solving a steady state model of a transient phenomenon. The orbital heat loads are calculated at discreate points and then the results are averaged over time.

Simulation Navigator

  • Solution 1

  • Solve

  • OK

     

  • The Solution Monitor allows you to view the progress of the solution.

    Wait for Completed to display in the Analysis Job Monitor dialog box, before proceeding.

  • No

     Review Results dialog box

  • Information window

  • Cancel

      Analysis Job Monitor dialog box

6: Analyze the temperature results

Display the temperature results on the top and bottom faces of the multi layer shells to view the impact of the Multi-Layer Insulation (MLI)

Simulation Navigator

  • Results

Post Processing Navigator

  • Thermal→Increment 1, 0 sec

  • Temperature - Elemental

  • Feature (Results tab→Display group→Edge Style list)

  • OK

     Post View dialog box

Note:

The temperatures vary from –38 °C to 90 °C at the outer layer.

Edit Postview (Post View group)

  • Shell

    Bottom

  • OK

     
Note:

If the result set does not change, try displaying a different result set, then plot bottom shell element temperatures again.

Note:

The temperatures vary around 23 °C at the internal layer.

  • Post View 1

  • 2D Elements (hide)

Note:

The bus instruments are at an average temperature of about 23 °C.

7: Observe the incident albedo heat flux over time

Plot the transient incident albedo heat flux.

Post processing Navigator

  • 2D Elements (show)

  • Absorbed Radiative Flux, ALBEDO - Elemental under Increment 1, 0 sec

Edit Postview (Post View group)

  • Shell

    Top

  • OK

     
Note:

If the result set does not change, try displaying a different result set, then plot top shell absorbed radiative flux again.

Animate (Animation group)

  • Animate

    Iterations

    Close

      Animate dialog box

Play (Animation group)

Stop (Animation group)

8: Save and close

Save and close your files when you are finished.

File

  • Save→Save All

File

  • Close→All Parts