Weekend launch preparations for the STS-128 mission include a test of a newly installed hydraulic power unit on a solid rocket booster and closeout of systems in the aft compartment of space shuttle Discovery. Launch is targeted for Aug. 24 at 1:58 a.m. from Launch Pad 39A at NASA’s Kennedy Space Center in Florida. The seven astronauts who will conduct the mission to the International Space Station will enter quarantine early Monday morning. It’s a standard precaution taken to prevent the astronauts from getting sick. The astronauts will fly to Kennedy on Wednesday from their training base at NASA’s Johnson Space Center in Houston.