CHOSHI, Japan (AP) ? The best part of being on the ocean for weeks at a time, says Sonya Baumstein, is the stars. The worst? Being wet, all the time.
Baumstein, an athlete from Orlando, Florida, waited for weeks to set out in her custom-designed rowboat from Choshi, a port east of Tokyo, headed for San Francisco. With a few last-minute adjustments to her supplies and a brief call to her parents, she rowed out of the marina on Sunday, a tiny sliver on the glittering horizon,
hoping to finish the 6,000-mile (9,600-kilometer) journey by late September and become the first woman to row solo across the Pacific. 
Only three other rowboats have made the journey, and no woman has ever done it alone.
Having already rowed the Atlantic to the Caribbean, the 29-year-old has a pretty clear idea of what all those weeks at sea will be like. With relatively clear skies, she may get the peaceful, starry night she was hoping for.
"It's very cool to see wildlife, but to watch the passing of the stars, because I row all night if it's good weather. To see the complete Milky Way," she said.
It's the paradox of modern-day adventuring that with new, extra-lightweight materials, solar panels and high-tech telecommunications, explorers and other extreme athletes can skate ever closer to survival's edge, under skeins of stars most of us rarely see.
Baumstein's rowboat, the "Icha," short for an Okinawan phrase meaning "once we meet we're family," is a lime-green, 23-foot (7-meter) -long vessel that weighs less than 660 pounds (300 kilograms). It has no motor or sail.
When the weather allows, she plans to row 14-16 hours a day, breaking her sleep to check her location ? she hopes to stay within the 100-kilometer (62-mile) -wide Kuroshio current that arcs across the Pacific, at least for the first part of the journey.
Baumstein rowed competitively in high school and at the University of Wisconsin, but was sidelined by a bad car accident. After recovering, she joined three men in rowing the mid-Atlantic from the Canary Islands to Barbados in January 2012. She has kayaked from Washington state to Alaska, stand-up paddle-boarded across the Bering Strait and bicycled 1,800 miles (2,900 kilometers) from the Mexican border to Seattle.
She likens the Pacific challenge to "climbing K-12 without oxygen."
But she's determined.
US woman sets out on 6,000-mile Pacific crossing by rowboat