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How Many Satellites can STK handle?

Created by Alexander Ridgeway, Modified on Tue, 18 Jun at 3:37 PM by Alexander Ridgeway

How many satellites can STK handle?
It depends. The answer, as with many software applications, is that it depends on various factors. Let’s explore the considerations and limitations of satellite handling in STK.

If you are loading satellites directly into the scenario, into the object browser, and visualizing each one as a satellite object, the number of satellites that an STK scenario can handle is dependent on the system it runs on. As each satellite is treated as a separate entity with its own properties and calculations, the computational load increases with the number of satellites. This approach is suitable for scenarios involving a relatively small number of satellites or a relatively powerful computer. In many cases, adding satellites directly to STK is not required. In some cases, it is. If adding satellites directly to STK is required, review the ‘Tips for handling many satellite objects in STK’, and consider setting some those options BEFORE you start adding a large number of satellites (below).

To overcome the limitations posed by loading and handling individual satellites, STK provides a powerful object called the Satellite Collection object in STK Premium Space. Instead of loading each satellite individually, you can group satellites into collections, which significantly enhances scalability. With Satellite Collections, you can efficiently manage and analyze large numbers of satellites, even reaching hundreds of thousands or more. Review the 'Benefits and Considerations when using a Satellite Collection Object' for more details (below).

The number of satellites that STK can handle depends on the approach you take. If you load each satellite individually, the limit is lower and constrained by the capabilities of the system running STK. Automation and certain approaches/tips increases this limit. However, by utilizing Satellite Collection objects, STK offers a scalable solution for managing and analyzing vast constellations or swarms of satellites. Satellite Collections reduce the computational load, simplify management, and provide enhanced analysis capabilities for large satellite groups.

Tips to handling MANY satellite objects in STK

These options should be attempted BEFORE adding all the satellites to the scenario

Consider halting the rendering of graphics. Here are some tips to improve render speed or remove graphics.
1. Closing the STK 3D Graphics Window and 2D Graphics Window. Then re-open these windows when finished.
2. Do not render the Orbits
  1. In the Scenario Properties, you can tell STK that by default, do not draw Orbits. This will stop STK from rendering the 'Orbital Yarn' as seen in the image above.
  2. Scenario Properties > 2D Graphics > Global Attributes > Under: Vehicles,
    1. Disable Show Orbits/Trajectories
    2. Disable Show Ground Tracks/Routes
    3. Disable Show Ground Markers
    4. Keep Enabled Show Orbit Markers
3. Sending the connect command for “BatchGraphics”
  1. Batch Graphics * On
    1. By sending this command, this sets the graphics in STK to update when you specify, instead of immediately upon adding the object. This will delay the objects being drawn in STK until you do the following things either start, step, reset or change the animation time or you change or move the 2D/3D windows.
  2. This feature improves STK graphics performance when you're manipulating attributes for a large number of objects.
  3. For more information go to:
    https://help.agi.com/stkdevkit/index.htm#../Subsystems/connectCmds/Content/cmd_BatchGraphics.htm
4. Consider Automation: Build a GUI-less STK Engine Application.
  1. This GUI-less application allows you to run analysis without STK rendering anything:
  2. https://www.agi.com/blog/2020/06/no-need-for-graphics-no-problem
5. Make sure STK is using your high performance graphics card instead of an integrated low performance one:
  https://www.agi.com/blog/2020/08/make-stk-look-beautiful-using-your-fancy-graphics
6. Update your graphics card driver.
  1. If you have an Nvidia graphics card, you can do one of the following.
    1. You can use the Geforce Experience to always have the latest card at:
      https://www.nvidia.com/en-us/geforce/geforce-experience/
    2. You can use the Nvidia downloader at:
      https://www.nvidia.com/Download/index.aspx?lang=en-us#installing
  2. If you are using another graphics card, go to the manufacturer's website to download the latest graphics card driver.
    1. More information from Microsoft:
      https://support.microsoft.com/en-us/windows/update-drivers-manually-in-windows-ec62f46c-ff14-c91d-eead-d7126dc1f7b6
Consider the timeframe of your scenario.
1. If you only need one hours’ worth of analysis, set your scenario time to only one hour. If you do that then your satellites will propagate only for 1 hour by default.
2. LEO satellites analysis, can you run just one orbit period? then set to ~90 min.
3. GEO satellite analysis, can you run just 1 second, or one orbit period? then set to 1 day.
Consider the propagators needed, use the fastest propagator without sacrificing accuracy and other considerations.
1. HPOP & Astrogator: Full/Complex force models but slowest relative speed
  1. HPOP and Astrogator are the highest precision orbit propagator, which can take longer to propagate depending on the settings. Sometimes it takes just a few seconds for single satellite and other times a few hours depending on the complexity of the sequences and the force models used.
  2. If the highest precision is not needed, consider using a more simplistic force model for the many satellites.
2. SPG4: propagator uses a TLE file.
  1. Use the Local Database to propagate satellites instead of the Online Database.
    1. The Local Database quickly adds the satellites from the TLE.
    2. The Online Database downloads the TLE for a single satellite, one at a time.
  2. Use the “Add from TLE File” instead of “Add from Standard Object Database”
  3. TLE epoch needs to be close to the Scenario Start so the propagation can run as fast and as accurate as possible. Old TLEs can cause problems in your analysis.
3. Two-Body/J2/J4: Simplistic Force Models, fastest speed.
  1. Best to propagate many satellites quickly.
Consider Automation: Build a For-Loop in Matlab/Python/Other.
1. These loops can be used to [Add a satellite, run the analysis, generate data, delete the satellite]. This process of looping through satellites can be faster. The key is deleting the satellite once you are through with the data.
Use a Multi-Track-Object.
1. MTOS are essentially multiple ephemeris files stored in a single Object used for Visualization. If you have already completed the analysis or you just want to visualize the satellites you propagated, an MTO can be used.
2. There are some example scripts in the STK Install to create an MTO from Objects in your scenario or convert an MTO to satellite objects in your scenario. These scripts are easy to use but might not be maintained by STK Development.
  1. "C:\Program Files\AGI\STK 12\Data\HtmlUtilities\Creating and Manipulating Objects\MTO to Object Converter\MTO Converter.htm"
  2. "C:\Program Files\AGI\STK 12\Data\HtmlUtilities\Creating and Manipulating Objects\Object to MTO Converter\Objects to MTO.htm"
Work with LSAS Tec-Support Team to come up with alternative approach to handling your analysis.

Benefits and Considerations when using a Satellite Collection Object:

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There are many benefits to the Satellite Collection object but also some limitations, so please consider the following.

Reduced computational load:
1. By using Satellite Collections, STK can perform calculations and simulations more efficiently. The computational burden is significantly reduced, enabling the analysis of vast constellations of satellites.
Simplified management:
1. Satellite Collections allow you to organize and manipulate groups of satellites as a single entity. This simplifies the process of creating, modifying, and analyzing large constellations or multiple constellations.
Enhanced analysis capabilities:
1. With Satellite Collections, STK offers specialized tools for analyzing and visualizing the behavior of large satellite groups. You can study the coverage, communication links, proximity operations, and other collective behaviors of the satellite constellation.
Simplified propagation:
1. When using Satellite Collections, individual satellites within the collection are represented by simplified orbit propagation models.
2. Two Body, J2, J4, or SGP4 orbit propagators are available for the Walker Tool, and the SGP4 is available for the Database option and external ephemeris is available for the Custom Option.
3. This allows for efficient processing and reduces the memory footprint.
4. To get around this limitation, propagate the satellites using HPOP, Astrogator, or ODTK then load the ephemeris files to the Satellite Collection object as Custom.
Reduction in Data Generated.
1. Individual satellites in STK have tens of thousands of data providers. Satellite Collection does not have this many.
2. To get around this limitation, STK allows you to add an individual satellite from the Satellite Collection by right Clicking on the object and selecting Promote to Satellite.

Additional Resources for Satellite Collection Object include.

Introductions to Satellite Collection Objects:
https://www.agi.com/blog/2022/02/stk-12-4-the-one-with-the-satellite-collection
Constellation Analysis using Chains:
https://www.youtube.com/watch?v=QhaGAPcppO0

If you have any further questions or need assistance, we are here to help! Our dedicated Tec-Support team is ready to provide prompt and personalized assistance tailored to your needs. Please don't hesitate to reach out by submitting a ticket by going to https://lsas-tec.freshdesk.com/support/tickets/new. We look forward to assisting you and ensuring a positive experience.

Thanks,

LSAS Tec-Support Team