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For the complete documentation index, see llms.txt.
Generate OEM (Orbit Ephemeris Message) files from state vectors. OEM files contain predicted satellite positions over a specified time range, useful for mission planning, conjunction analysis, or sharing with external systems. Access: Click Generate Ephemerides on the State Vectors page top-right corner. The Generate Ephemerides modal guides you through four steps: Ephemerides Generation

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Step 1: State Vector Selection

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Select Spacecraft

Choose a spacecraft from the dropdown. The list shows spacecraft names with colored satellite icons.

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Select State Vector

After selecting a spacecraft, choose a state vector from the dropdown. Each option shows the state vector ID and epoch date/time. Empty State: If no state vectors are available for the selected spacecraft in the last 30 days, you can:
  • Click Import State Vector to open the import dialog
  • Click Run Orbit Determination to configure OD

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Include Covariance Data

Toggle whether to include covariance matrix in the OEM file:

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Step 2: Time Range Configuration

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Time Step

Use the slider to set the interval between data points (1–60 minutes).
  • Smaller step = more data points, larger file
  • Larger step = fewer data points, smaller file

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Start Date & Time

Select the start date from the 7-day calendar (use arrows to navigate weeks) and enter the start time in 24-hour UTC format (e.g., “08:30”). Default: 00:00 UTC

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End Date & Time

Select the end date and enter the end time. Default: 23:59 UTC
Dates are limited to ±30 days from the state vector epoch. Total duration cannot exceed 30 days.

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Step 3: Reference Frames

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Time System

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Ephemerides Reference Frame

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Covariance Reference Frame

Only available when covariance is enabled in Step 1.

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Step 4: Review & Generate

Review your configuration before generating: State Vector Card
  • Spacecraft name
  • State Vector ID
  • Epoch date and time
Time Range Card
  • Start and end date/time (UTC)
  • Time step in minutes
  • Calculated number of data points
Reference Frames Card
  • Time system
  • Ephemerides frame
  • Covariance frame (if enabled)
Click the Edit button (pencil icon) on any card to jump back to that step.

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Generate OEM

Click Generate OEM to create and download the file. Loading states:
  1. “Sending request to server…”
  2. “Downloading file…”
On success:
  • Toast notification: “OEM generated successfully”
  • File downloads automatically
  • Modal closes
  • Step tabs: Click any step name to jump directly to it
  • Next: Validates current step and proceeds
  • Back: Returns to previous step (hidden on Step 1)
  • Cancel: Closes modal without generating

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Error Handling

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Output

Format: OEM (Orbit Ephemeris Message), CCSDS standard text format Filename: oem_{stateVectorId}_{timestamp}.txt

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Constraints