STS-104, Mission Control Center
                             Status Report # 11
                    Tuesday, July 17, 2001 - 7 a.m. CDT

 Shuttle and station crews set aside work on a leaky ventilation valve and
 pressed forward with activation of the new Quest airlock and a dry run of
 the steps they'll use for the first space walk using the new station
 doorway to space.

 The practice run included a successful lowering of the airlock's pressure
 to 10.2 pounds per square inch for the first time in space.

 Lead Flight Director Paul Hill said troubleshooting on the valve -- and
 work the day before to get air bubbles out of an airlock water cooling
 line -- have put the combined crew about half a day behind its timeline.
 Among the tasks delayed was a relocation of the hatch from the junction
 of the airlock and the Unity module to its final position between the
 airlock's crew and equipment lock sections.

 The second space walk of the flight remains on schedule for Tuesday
 night. Mission Specialists Mike Gernhardt and Jim Reilly are scheduled to
 step out of the space shuttle's airlock about 9:30 p.m. The objective of
 the 5« hour foray is to mount one high-pressure oxygen and one
 high-pressure nitrogen tank on the shell of the new airlock to provide
 consumables that would allow expeditioners to leave the station in
 American space suits for construction and maintenance work without a
 shuttle present. Russian space suits can be used from the airlock as
 well.

 The crews closed the hatches between the two spacecraft at 6:30 a.m.
 Tuesday to begin lowering Atlantis' cabin pressure to that same 10.2
 pounds per square inch mark. This measure helps purge nitrogen bubbles
 from the space walkers bloodstreams, and is augmented by the space
 walkers pre-breathing pure oxygen. All crewmembers reviewed the
 procedures for the space walk prior to closing the hatch between the
 shuttle and the station's Destiny Laboratory.

 Mission Specialist Janet Kavandi and Expedition Two Flight Engineer
 Jim Voss took the lead in troubleshooting the suspected leak in an
 Intermodule Ventilation (IMV) assembly. The series of fans and valves
 circulates air between station modules and connects the airlock to the
 station's environmental control and life support system. The pair wasn't
 able to pinpoint the problem with the valve, but did install a cap that
 stopped the leak. Should replacement be necessary, several valve
 replacement options are available to the flight control team and crew
 onboard.

 The delays have led flight managers to study the possibility for an extra
 day of docked operations and a shuttle mission extension to ensure all of
 the mission's work can be completed.

 Shuttle Commander Steve Lindsey, Atlantis’ Pilot Charlie Hobaugh and
 Station Commander Yury Usachev took time late Monday night to answer
 questions from reporters from CBS, Space.com and KNBC-TV of Los Angeles.

 The eight people on orbit are scheduled to go to bed about 8 a.m. and
 awaken at 4:04 p.m. The next mission status report will be issued about
 6 p.m. Tuesday or as events warrant.