CAPE CANAVERAL, Fla. – Atlantis' six astronauts did some last-minute studying for their 11-day mission Tuesday as the weather forecast for Wednesday's space shuttle launch continued to look good.
The shuttle's commander, Brent Jett, and pilot, Chris Ferguson, used a Gulfstream jet to simulate landing the shuttle, while other crew members reviewed the complicated construction tasks ahead of them.
The astronauts will resume building the space station for the first time since the Columbia disaster 3 1/2 years ago, adding a 17 1/2-ton truss to the orbiting outpost. Their mission includes three spacewalks.
Forecasters said there was only a 30 percent chance that weather would prohibit the shuttle from blasting off as planned at 12:28 p.m., a slight worsening of the outlook from the previous day. But the launch window opens before Florida's afternoon summer thunderstorms normally blow through.
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No major technical problems were reported a day before launch. Technicians had noticed a slightly hazardous reading of gaseous oxygen in the rear of the shuttle, but they considered it the result of a bad connection during fueling of the spacecraft's power cells and said they were not concerned.
"The first couple of inches is the hardest part of the whole flight," said LeRoy Cain, chairman of the mission management team. "Anxious anticipation is how I would describe it."
Atlantis originally was scheduled for liftoff Aug. 27 but was delayed, first by a lightning strike at the launch pad, then by Tropical Storm Ernesto.
NASA had started to move Atlantis back to the hangar because of Ernesto but changed course last week. By sending the shuttle back to the launch pad, NASA gained enough time to prepare for a launch this week.
If Atlantis doesn't get up in the air this week, the next chance probably won't come until the end of October.
The Russians plan on Sept. 18 to launch a Soyuz capsule ferrying two new station crew members and the space station's first female tourist, Dallas-area entrepreneur Anousheh Ansari. Officials with both space agencies did not want the shuttle and Soyuz at the space station simultaneously, for fear it would create a traffic jam.