Satellite Database TLE Source

Specifies the satellite database source. Choose from one of the following options:

• Import from Online Source. Select an online database source:
• • AGI Server - You must be connected to the internet to utilize this source.
  • Space Track Server -You must be connected to the internet, and will have to log into Space Track to utilize this source.
• Import from File. Browse to the TLE file to be used as the source.
• Use Default Satellite Database. Uses the default Satellite database as the source.

Switching Method. Defines when to switch between TLE sets:

Epoch. Switch between TLE sets based on the epoch of the TLE.

Mid-Point. Switch between TLE sets based on the mid-point between two TLE epochs.

TCA. Switch between TLE sets based on the time of closest approach. Calculated by propagating the first and second TLE sets over the time period between their respective epochs, and then determining the point at which the two paths are nearest each other. This option provides the smoothest possible switch between two TLE sets.

Additional Options

To allow the satellite's designated TLEs to be automatically updated from the selected source prior to each propagation, select On propagation, automatically retrieve elements.

To apply your changes to the propagator defaults, select Update SGP4 TLE Source preferences.

Search results may be further filtered by TLE availability. Normally, if there is not a TLE associated with an SSC number meeting the search criteria, then that object is not displayed in the results table. However, if you wish to see these objects listed, turn off Filter search results by TLE availability. Note that you cannot create a Satellite for an object with no TLEs.

Note: If the TLE source is a file and contains TLEs for SSCs that are not listed in the satellite database file (i.e., the *.sd file), then these SSCs will be added to the results table. This allows you to choose any SSC in a TLE file whether or not the satellite database file has an entry for it. This functionality replaces that of the obsolete Insert Satellite from TLE File tool.