Live at KSC: Weather only obstacle for Endeavour

LIVE IMAGES: The images above are from live video feeds in the Launch Complex 39 area at Kennedy Space Center, where shuttle Endeavour is being readied for launch Saturday. They will automatically refresh to the most up-to-the-minute image every 30 seconds.

Space shuttle Endeavour's countdown to a 7:39 p.m. Saturday launch is proceeding smoothly, NASA officials said this morning.

"Our launch countdown preparations are proceeding on schedule and without any significant issues," said Steve Payne, NASA test director.

Weather remains the primary concern.

"We are expecting thunderstorms to affect the countdown, especially in the afternoon," said Todd McNamara, shuttle weather officer for the Air Force's 45th Weather Squadron.

Those storms are expected to diminish closer to launch time, McNamara said, but there remains a 60-percent chance that isolated storms could keep Endeavour grounded during a 10-minute launch window opening at 7:34 p.m.

The storms are not expected to be a problem for the start of fueling at 10:14 a.m. Saturday.

NASA believes a recent tanking test proved it has solved hydrogen gas leaks that scrubbed countdowns on June 13 and June 17.

Barring any new problems, Endeavour's crew of seven astronauts, led by commander Mark Polansky, would begin strapping into their seats in the orbiter at 4:19 p.m.

If Saturday's launch scrubs, the odds of bad weather decrease to 40 percent Sunday and 30 percent Monday.

The Air Force's Eastern Range, which tracks vehicles launching from the Space Coast and makes sure they don't endanger populated areas, has warned boaters to stay out of a specified launch hazard area off Cape Canaveral between 5 p.m. and 8:45 p.m. Saturday. Violations carry penalties of up to six years in prison and fines up to $250,000.

Check out this map showing the hazard area, and read the release here.

Also see this KSC press release detailing local airspace, road, bridge and waterway closures on launch day.

Endeavour's crew will deliver to the International Space Station the final piece of Japan's Kibo science lab, a nearly 8,400-pound "front porch" that will expose experiments to space.

Spare parts including six new batteries for the station's oldest solar array wing will also be delivered.

Those parts will be installed and stowed over the course of five spacewalks during a planned 16-day mission.

If able to launch Saturday, Endeavour would target a 12:20 p.m. July 27 landing at KSC.

IMAGE NOTE: Click to enlarge the images taken this morning by Florida Today's Mike Brown near launch pad 39A at Kennedy Space Center. News photographers were setting up remote cameras in advance of Endeavour's planned 7:39 p.m. liftoff.