When Gemma Kirby goes from zero to 60 mph, it only takes her about 15 feet.
And when she comes to a stop in an air bag 104 feet from her cannon, it's usually about 2.4 seconds after her ride began.
The Associated Press spoke with the Minnesota native who will be shot out of a cannon for the 500th time during Saturday's performance of Circus Xtreme in Philadelphia.
Circus Xtreme is an offshoot of the Ringling Brothers and Barnum & Bailey circus, featuring some of the most daredevilish acts.
According to Kirby's biography on the Circus Xtreme website, she was born in Minneapolis and had a childhood that prepared her well for a circus life because her family moved 15 times.
But the Tampa Bay Times reports the family (then living in Alaska) made the last move at Gemma's request because she wanted to train to be an aerialist at Circus Juventas in St. Paul. Kirby took 35 hours of classes per week for 5 years beginning at age 12, the Times says.
After her training at Circus Juventas, Kirby worked as a trapeze artist with several circuses, then was finishing her psychology degree at the University of Minnesota when Ringling Brothers recruited her (via a Facebook message, the Greenville Journal reports) to become a human cannonball.
Every shoot involves a host of calculations including the temperature and humidity in the arena, the AP says. And because the cannon is calibrated to her weight, Kirby can't lose or gain more than a few pounds.
There are no days off for a human cannonball – Kirby reached her "cannonversary" on her 365th straight day – and she says it's not something she'll be doing 50 years from now. But she's happy now, telling the Tampa Bay Times "It's as close as you can come to really flying."