Atlantis continues to prep, with a practice countdown today. STS-115 promises to be among the most challenging shuttle missions to date, particluarly with regard to a tight timeline.
"With three planned spacewalks - two of them back-to-back - alongside shuttle heat shield inspections and the deployment of new solar panels outside the ISS, Atlantis' 11-day mission promises to be a challenging one for its astronaut crew. ...NASA managers have called the STS-115 mission the most challenging to date for the shuttle program, though subsequent flights are expected to only increase in complexity."
Atlantis will deliver a 17 ton segment to the space station, along with a new set of solar arrays to provide power to the ISS. Liftoff is scheduled for Aug. 27.