Astronaut Frank Culbertson watched from the Space Station as the attacks unfolded on the ground.

When astronauts describe the feeling of sailing around space, looking at our planet from hundreds of miles above, they often invoke the phrase "orbital perspective," a shorthand for the emotional, psychological, and intellectual effects of seeing "the Earth hanging in the blackness of space." This experience is characterized by not merely awe, but, as astronaut Ron Garan puts it, "a sobering contradiction. On the one hand, I saw this incredibly beautiful, fragile oasis -- the Earth. On the other, I was faced with the unfortunate realities of life on our planet for many of its inhabitants."

This tension was particularly poignant on 9/11, when the effects of violence on Earth were actually visible from space, as captured in the photograph above. At the time, three people were not on Earth: Russian cosmonauts Mikhail Tyurin and Vladimir Dezhurov, and American Frank Culbertson, making Culbertson the only American not on Earth during the 9/11 attacks.

Over the course of that night and into the following few days, Culbertson wrote a letter to those at home, and his words echo that orbital perspective Garan describes. "It's horrible to see smoke pouring from wounds in your own country from such a fantastic vantage point," he wrote. "The dichotomy of being on a spacecraft dedicated to improving life on the earth and watching life being destroyed by such willful, terrible acts is jolting to the psyche."

Culbertson told of how the day had unfolded on the Space Station:

I had just finished a number of tasks this morning, the most time-consuming being the physical exams of all crew members. In a private conversation following that, the flight surgeon told me they were having a very bad day on the ground. I had no idea...

He described the situation to me as best he knew it at ~0900 CDT. I was flabbergasted, then horrified. My first thought was that this wasn't a real conversation, that I was still listening to one of my Tom Clancy tapes. It just didn't seem possible on this scale in our country. I couldn't even imagine the particulars, even before the news of further destruction began coming in.

Vladimir came over pretty quickly, sensing that something very serious was being discussed. I waved Michael into the module as well. They were also amazed and stunned. After we signed off, I tried to explain to Vladimir and Michael as best I could the potential magnitude of this act of terror in downtown Manhattan and at the Pentagon. They clearly understood and were very sympathetic.

I glanced at the World Map on the computer to see where over the world we were and noticed that we were coming southeast out of Canada and would be passing over New England in a few minutes. I zipped around the station until I found a window that would give me a view of NYC and grabbed the nearest camera. It happened to be a video camera, and I was looking south from the window of Michael's cabin.

The smoke seemed to have an odd bloom to it at the base of the column that was streaming south of the city. After reading one of the news articles we just received, I believe we were looking at NY around the time of, or shortly after, the collapse of the second tower.

As he signed off, Culbertson reflected, "I miss all of you very much."