Where in the Galaxy is the Sun?

In our day-to-day lives, we don’t take much time to think about where exactly the Sun is. It’s easy to tell if it’s “out” or not, and most of us are comfortable with this level of specificity alone. However, the location of the Sun in space is crucial to many space missions. More specifically, the precise location of the sun is crucial. Not knowing where the Sun is relative to a spacecraft can lead to mission-ending thermal failures.

While there are algorithms that give approximate locations of the sun at any given moment, Systems Tool Kit (STK) provides exceptional accuracy. There is a three-step approach with STK that ensures you have access to the best estimates for your scenarios. These steps are:

1. Access high fidelity JPL ephemeris data in the inertial frame 
2. Account for aberration (the fact that light travel is not instantaneous and so by the time visual data can be recorded, the data is, itself, outdated) 
3. Convert into Earth frames 

And voila! Now you really know where the sun is. For an in-depth mathematical explanation of these steps, consult the article, ‘Sun Vector Calculation’ on our website!