Discovery Date Tied To Fishing Season In Japan

Shuttle Discovery safely reached its Kennedy Space Center launch pad Tuesday and it now faces a launch deadline dictated by congested traffic at the International Space Station and the fishing season off the coast of Japan.

Discovery and seven astronauts are tentatively scheduled to blast off at 1:36 a.m. Aug. 25 on a space station outfitting mission.

NASA still must fix a faulty booster rocket steering system, but officials think Discovery will be ready to fly on time.

"We definitely believe that with the work we know we have ahead of us right now, we can make this launch window," NASA Discovery Flow Manager Stephanie Stilson said.

But if Discovery delays past Sept. 3, NASA would yield for the debut launch on Sept. 10 of a robotic Japanese space freighter that will play a critical station resupply role after the planned 2010 retirement of NASA's shuttle fleet.

A Russian crew rotation mission will block traffic to the station between Sept. 21 and Sept. 28. So Japan only will have launch opportunities from Sept. 10 through Sept. 20, and Sept. 29 and Sept. 30, before a month long cutout for fishing season.

Japan's Tanegashima Space Center is located on Tanegashima Island at the southern end of the East Asian archipelago. In the event of launch failures, wreckage would fall into the Pacific Ocean in an area where the nation's fishing industry and its powerful unions operate. So launches from Tanegashima are limited during peak fishing seasons, one of which stretches throughout October.

The next opportunity to launch the Japanese HTV cargo carrier would come between Nov. 1 and Dec. 31.

Discovery's rollout Tuesday had been delayed a day while engineers analyzed the apparent failure of a valve on the steering system of the shuttle's left solid rocket booster.

NASA plans to swap out the valve, an associated auxiliary power unit and a hydraulic pump -- work that likely can be squeezed into an otherwise tight processing schedule.
NASA has to wedge its seven remaining shuttle missions into an increasingly intricate traffic pattern at the station.

Two Russian Soyuz crew rotation missions now will be launched each spring and fall to support an expanded crew of six. That will create four, 10-day periods each year when visiting vehicles cannot dock at the outpost.

Russia also launches up to five robotic Progress cargo carriers each year, and now both European Jules Verne and Japanese HTV cargo carriers also will be flying to the outpost.

Complicating matters, NASA encounters lengthy periods when the sun angle on the station is such that the outpost can't generate enough power to support a docked shuttle mission.

Discovery rolled out Tuesday despite a soggy crawlerway and the threat of being caught in a lightning storm in transit to launch pad 39A.

Discovery's astronauts will jet to KSC today to take part in a two-day practice countdown.

A firm launch date will be selected at a readiness review Aug. 18 here at KSC.

ABOUT THE IMAGES: Click to enlarge the NASA image (top) of shuttle Discovery after it reached Kennedy Space Center's launch pad 39A on Tuesday. Traveling on a soggy crawlerway, the shuttle's transporter was stopped several times so technicians could clear mud from its cleats and bearings. The 3.5-mile trip from the Vehicle Assembly Building took 12 hours to complete. Photo credit: NASA/Troy Cryder. The second image shows a Japanese rocket sitting on an oceanside launch pad at Tanegashima Space Center on the southern tip of Japan. Photo Credit: Japan Aerospace Exploration Agency (JAXA).