Flashing the ISS

In case you missed this story from earlier this week, I wanted to point out an interesting historical event.

For years, people have wondered if the astronauts aboard the International Space Station could see a flashlight, or perhaps laser pointer, pointed at it from the Earth’s surface. While it was theoretically possible and tried a number of times, it had never been done successfully… until March 4, 2012.

Texan amateur astronomers of the San Antonio Astronomy Association and the Austin Astronomy Society put together a plan to prove the possibility. On March 4, these amateur astronomers implemented their experiment. They left the urban lights for dark skies (and as importantly, a dark ground from the vantage point of the ISS) at the Lozano Observatory. There, they set up a one-watt blue laser and a pair of bright spotlights, complete with a simple, yet effective, system to strobe the spotlights: people holding wooden boards. Timing had to be calculated precisely for a couple of reasons. Not only did the ISS have to pass their dark location overhead at night, but it had to be such that the ISS had a view of the Earth without the Sun blinding their view; after all, it is the bright sunlight reflecting off of the ISS that makes is so bright and visible to us on Earth.

Their timing, and a few months of planning, paid off. As the ISS came overhead of the anxious amateur astronomers, they flipped on the laser and began alternating the spotlights on-and-off in two-second intervals. ISS Expedition 30 Flight Engineer, Don Pettit, had been involved in the planning of the experiment and had been communicating with the group in the days leading up to the attempt. At the time that the ground crew began their attempts to flash the space station, Pettit was situated in the ISS Cupola, eyes peeled with his camera snapping pictures. The ISS pass was complete within a few minutes, and the group had to anxiously await feedback from Pettit. The next day, their confirmation came.
Image showing the flash experiment from the ISS.

(Click image for larger size / Image Credit: Don Pettit/Fragile Oasis)

Success! According to Keith Little, Marketing Director of the San Antonio Astronomical Association, Don Pettit told him that not only could he see the spotlights, but easily saw the laser by itself!

It’s wonderful when astronauts orbiting the Earth can work together with amateur astronomers to collaborate on experiments such as this, and its icing on the cake when they make history in the process.

For more information about the event, you can view a video of the experiment from the ground here and listen to an episode of 365 Days of Astronomy pertaining to the event.