On Wednesday, Jan. 4, 2012, NASA captured stunning images
of the International Space Station (ISS) in Earth orbit passing directly in front of the moon. This unique alignment provided for some spectacular perspectives of the space station against the lunar backdrop.
Curious to know from where this image was taken, I quickly re-created the transit with STK
. The entire process took 15 minutes!
Only knowing the approximate location (near Houston) I used STK’s Vector Geometry Tool
to identify the path where the line between the moon’s center and the ISS intersected the Earth’s surface in the Houston area. Interestingly enough, that line passed right through Johnson Space Center.
Based on my analysis, the photographer was standing somewhere just East of that line. I determined this from the fact that the ISS passes just above the moon’s center in the captured images that I was able to re-create by quickly moving the viewer location. STK provides a great platform for prediction and forensic analysis of sensor collections like this.
You can build this simple scenario yourself in 10 easy steps with STK
1) Create a new STK scenario from Jan. 3-5, 2012
2) Add a Facility at Houston from the City Database
3) Add the ISS satellite from the Satellite Database
4) Add the Moon to the scenario as a planet object
5) Add a Vector from the Moon to the ISS
6) Add a Point that projects the Moon-ISS Vector to the local Houston XY plane
7) Use 3D editing to move the facility along the path of the ISS-Moon Vector Intersection
8) Add a 0.5 degree rectangular sensor to the Houston Facility pointing at the moon
9) Calculate Access from the sensor to the ISS to identify the times when the ISS passes through the sensor
10) Set a 3D Window to replicate the sensor view and further refine the facility location