Growing up, Heather “Lucky” Penney had a lot of different creative interests: She danced ballet, marched in her high school band, and took theater. But the one interest that would change her life forever was aviation.

On September 11, 2001, Penney was one of the first DC National Guard F16 pilots scrambled from Andrews Air Force Base after the attacks. Her mission was to take down the fourth hijacked plane that was en route to Washington, DC, by any means necessary. There wasn’t enough time to arm her jet with missiles; her jet was the missile.

For many years, Penney, who now works at Lockheed Martin Aeronautics Company and is working to share the story of the Women Airforce Service Pilots (WASP), never spoke publicly about her 9/11 experience. In 2011, she told the Washington Post: “I genuinely believed that was going to be the last time I took off.”

Penney was 25 at the time and the first female fighter pilot in her DC Air National Guard unit. “A young baby fighter pilot,” she told a crowd during a lecture last year at the Smithsonian National Air & Space Museum. She signed up during graduate school as soon as Congress lifted the combat restriction for women in the early 1990s.

Penney, who served in the National Guard until 2016, and her unit had just returned from training out of state. Many of her fellow guardsmen had taken off the beginning of that week to spend time with family, but she was single at the time and clocked in at work as usual. “Really, all I did that day was show up for work,” she said during her lecture.

During a morning briefing, she and other members of her unit heard the news that a plane had hit the World Trade Center. They wondered how that could have happened. It must have been one of those small, sightseeing planes, they mused. “It wasn’t anything that triggered us,” she said.

Moments later, they learned the second tower had been hit and knew this was no accident. “We saw the footage of these airliners crashing into the Trade Center and we were absolutely stunned,” Penney recalled. They immediately went into mission planning mode, despite not knowing what they were really planning for.

After the Pentagon was hit by a third plane, Penney’s commanding officers finally got the authorization to get their fighter jets airborne. Their jets could be armed with missiles within an hour, but they needed to take off right away. As she and Colonel Marc "Sass" Sasseville, her wingman, quickly pulled on their gear, he told her: “I’ll take the cockpit.”

“I knew that I would take the tail,” Penney said soberly, even though she’d only recently become combat-mission ready. United Flight 93, the Boeing 757 aircraft they were targeting, weighed nearly nearly seven times the weight of their F-16 fighter jets. (It was also the airline that Penney’s father flew for as a commercial pilot.)

“It was because I knew that if anything in my life mattered, that was it. And I could not screw it up.”

Preflight preparation usually takes about half an hour. Every pilot knows that mistakes happen when you deviate from your routine, Penney told the Smithsonian audience. She recounted how she ran up to the crew chief, dropped her things to shake his hand, and quickly flipped through the necessary forms. Sasseville yelled from his jet, “Lucky! What the hell are you doing? Get in the jet!”

“It was not because I was negligent,” Penney explained. “It was because I knew that if anything in my life mattered, that was it. And I could not screw it up.”

In the air, Penney and Sasseville never found anything. They’d learn about an hour into their mission that United Flight 93 had crashed in a field in Pennsylvania after its passengers overtook the hijackers to prevent them from reaching their target.