CAPE CANAVERAL, Fla. (AP) — The countdown began Saturday for NASA's next shuttle launch, an unusually long space station mission by Endeavour.

The shuttle's seven astronauts arrived early in the morning, delayed for hours by stormy weather between their home base in Houston and the Kennedy Space Center. The countdown clocks began ticking shortly afterward.

Commander Dominic Gorie said he and his crew were excited about getting their 16-day mission under way and were hopeful the weather would cooperate.

Endeavour is scheduled to blast off at 2:28 a.m. Tuesday.