Workers clean the mobile launcher platform on which sits Space Shuttle Atlantis.

Workers clean the mobile launcher platform on which sits Space Shuttle Atlantis. They are standing in front of one of two tail service masts on either side of the Shuttle, in front of each wing. The masts support the fluid, gas and electrical requirements of the orbiter’s liquid oxygen and liquid hydrogen aft T-0 umbilicals. Launch on mission STS-104 is scheduled for 5:04 a.m. July 12. The launch is the 10th assembly flight to the International Space Station. Along with a crew of five, Atlantis will carry the joint airlock module as primary payload