STS-104, Mission Control Center Status Report # 13 Wednesday, July 18, 2001 – 6 a.m. CDT

Six arms worked together outside the International Space Station again today to install supply tanks for the
new joint airlock, accomplishing a bonus oxygen tank installation during a 6 hour, 29 minute space walk.

Four of the arms belonged to space walkers Mike Gernhardt and Jim Reilly. Two robotic arms also were
called into service – the shuttle’s Canadarm and its big brother, the station’s Canadarm2. Station Flight
Engineers Susan Helms and Jim Voss were at the station arm’s controls, while Mission Specialist Janet
Kavandi guided the shuttle limb.

The space walk got off to a slightly delayed start at 10:04 p.m. CDT Tuesday after the station’s primary
Command and Control computer had to be restarted. The computer, needed to guide the station arm as it
lifted the high-pressure oxygen and nitrogen tanks out of the shuttle cargo bay and into position alongside
the new airlock, was back in business shortly after 8 p.m., allowing first motion of the arm by 9 a.m.

Gernhardt and Reilly, supported by their six colleagues inside the shuttle and station, latched the first two
dog house-shaped tank assemblies into place without difficulty, so shuttle and station Flight Directors Paul
Hill and Mark Kirasich decided to move ahead with installation of the third tank at 1:41 a.m.

The second space walk of the mission concluded at 4:33 a.m. CDT Wednesday. It was the 66th space walk
in shuttle program history, and the 23rd devoted to International Space Station assembly. So far, STS-104
space walks have lasted 12 hours, 28 minutes.

The crews will have an extra day to prepare for the third and final planned space walk of the flight, which
now is scheduled for Friday. Mission managers decided Tuesday to add the additional docked day to give
the joint crew adequate time to ready the new airlock for its first use.

The two crews are about half a day behind schedule due to a small water leak that occurred when the
astronauts were linking the new airlock to the station’s Moderate Temperature Loop. The crews will resume
troubleshooting a leaky air valve in an Intermodule Ventilation (IMV) unit on the rear, right side of the
station’s Unity node after wakeup scheduled for 4:04 p.m. today.

With the space walk complete, STS-104 Commander Steve Lindsey and Pilot Charlie Hobaugh, who also
was the inside coordinator for the space walk, began another hour-long series of automated steering jet
firings to reboost the station’s altitude.

The next mission status report will be issued about 6 p.m. Wednesday or as events warrant.