WASHINGTON -- Frank Culbertson felt like he was thrust into a Tom Clancy novel when he first saw the plume of smoke streaming away from lower Manhattan on Sept. 11 more than a decade ago.

On Sept. 11, 2001, NASA astronaut Frank Culbertson was the lone American off the planet. Culbertson and two Russian cosmonauts were orbiting the Earth aboard the International Space Station as members of the Expedition 3 crew. In this video, NASA shares footage captured by Culbertson just after the World Trade Center attacks. Credit: NASA
 
Halfway through Clancy's "The Sum of All Fears," which features a plot including a terrorist attack on the United States, Culbertson was alerted to the unfolding events of Sept. 11 by a NASA physician in Houston.

Culbertson, then a two-time space shuttle flier, was one month into a stint as commander of the International Space Station. He was joined by two Russian cosmonauts, making Culbertson the lone American away from Earth that day.

After hearing the news from mission control, Culbertson raced to a laptop computer to check the space station's flight path. Sure enough, the orbiting laboratory was just a few minutes away from flying over the East Coast of the United States.

Culbertson scurried around the space station, grabbed a video camera and found a window in the Russian service module looking toward New York City. He was stunned by what he saw.

A thick column of black smoke was rising from ground zero. Winds swept the smoke south over Brooklyn and New Jersey before the plume dissipated well offshore over the Atlantic Ocean.

"It was clear to me we were under attack," Culbertson said. "It broke my heart to see the country affected like this."

After comparing the time stamp on his photos with the chronology of events on Sept. 11, Culbertson believes he saw the aftermath of the second World Trade Center tower collapsing.

Moving through the void at more than 17,000 mph, fast enough to circle the planet in 90 minutes, the space station quickly flew over New York and the attack's grotesque scar faded from view.

But an hour-and-a-half later, the space station was back over the United States and Culbertson spotted the damaged Pentagon.

His thoughts turned to his family and friends. A quick check on his wife and children confirmed they were OK.

In this image snapped on the space station on Sept. 11, 2001, smoke pours from the World Trade Center site in lower Manhattan. Credit: NASA

"With all the people I know in the military, people I'd flown with and met through business, I figured I would know someone affected by this tragedy," Culbertson said.

One of Culbertson's Naval Academy classmates, Charles Burlingame, was one of nearly 3,000 people who perished in the Sept. 11 attacks. Burlingame, whose nickname was Chic, was captain of American Airlines Flight 77, the hijacked plane that crashed into the Pentagon.

Culbertson penned a letter to readers on Earth in the hours and days after the attacks, reflecting on the events of Sept. 11. You can read the text of the letter on NASA's website.

Last week, Culbertson visited the Naval Academy and the World Trade Center site in Manhattan to commemorate the 10th anniversary of the attacks.

One month after the terrorist strike on America, Culbertson was an eyewitness to the launch of U.S. air raids against Taliban and al Qaeda strongholds in Afghanistan.

"You could easily spot Afghanistan from orbit because it was a black hole," Culbertson said. "There are no lights."

Culbertson, now a senior vice president at Orbital Sciences Corp., described his memories to coworkers last week.

"I could see flashes of light, the cruise missiles going into Kabul, strings of B-52 bombs going off," Culbertson said. "I was seeing the invasion of Afghanistan. It was the first time I'd seen combat from space."

After 129 days in orbit, Culbertson returned from his tour aboard the space station on Dec. 17, 2001.