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Check Current Position of a Satellite ​

This workflow demonstrates how to move a point in the visualizer to a satellite's position at a specific time. The satellites are identified by their NORAD Catalog Number.

We'll use two main functions:

  • setTime to set the simulation time
  • mov2sat to position the satellite based on its TLE at that time

Here is the code that you can run directly in the integrated editor:

javascript
// Set simulation to current time and move satellite
let now = new Date();
setTime(now);
mov2sat("sat", "60562", now);

TIP

If you were following along with the previous workflow you might want to start your script with reset() which will return the state of the scene to the default one. Having it up there is particularly useful when you are iterating over your script.

Since this is just JavaScript, you can calculate dates however you prefer. For example, to see where the satellite was one hour ago:

javascript
let currentDate = new Date();
let previousHour = new Date(currentDate.getTime() - (60 * 60 * 1000));

setTime(previousHour);
mov2sat("sat", "60562", previousHour);

Or to check its position at a specific date and time:

javascript
let specificDate = new Date('2025-01-01T15:25:00Z');
setTime(specificDate);
mov2sat("sat", "60562", specificDate);

The setTime function updates time-dependent elements in the scene, specifically the Sun's position relative to Earth to match the illumination conditions at that time. Note that setTime does not move the satellite - you need to use mov2sat to position the satellite at the desired time.

WARNING

You will be fetching the most recent TLE from Celestrak. Keep in mind that the further into the future or the past with respect to now that you go the less accurate the position will be.

Finding NORAD IDs ​

You can easily find the NORAD ID of satellites on Celestrak. Simply search for the satellite by name or use other relevant categories (such as weather satellites, GPS, etc.) to find the NORAD ID.

The NORAD ID is a unique identifier assigned to each satellite, and is necessary to fetch the satellite's position in real-time.

Example Resources ​

  • Celestrak NORAD Satellite Catalog: Search for satellites and their corresponding NORAD IDs.
  • TLE Data: A text file listing current Two-Line Element (TLE) sets for satellites, which are required to calculate their positions.