Expedition 2 was the second expedition to the International Space Station.

Crew

• Yury Usachev (4), Commander - Russia
• Susan Helms (5), Flight Engineer - U.S.A.
• James Voss (5), Flight Engineer - U.S.A.

(1) number of spaceflights each crew member has completed, including this mission.

Mission parameters

• Perigee: 384 km
• Apogee: 396 km
• Inclination: 51.6°
• Period: 92 min

• Docked: March 10, 2001, 06:38 UTC
• Undocked: August 20, 2001, 14:51:30 UTC
• Time Docked: 163 days, 8 h, 13 min, 30 s

Mission objectives

The second group of space explorers arrived at the International Space Station in March 2001. The three-member Expedition 2 crew successfully launched on March 8, 2001 on Space Shuttle Discovery during mission STS-102. They officially began their four-month tour aboard the ISS on March 18, 2001 and returned to Earth on mission STS-105, August 22, 2001 after having spent 163 days aboard the station and 167 days in space.

During this expedition, research facilities to be launched to the Space Station include a Human Research Facility, two EXPRESS (Expedite the Processing of Experiments to the Space Station) Racks, one of which contains the Active Rack Isolation System and the Payload Equipment Restraint System. Over the life of the Space Station, these facilities will support a wide range of experiments that could improve life on Earth and in space. They will also prepare the Destiny laboratory for experiments to be conducted.

A major focus will be on gaining a better understanding of how to protect crew members from radiation while working and living in space. Radiation exposure in high doses over long periods of time can damage human cells and cause cancer or injury to the central nervous system.

There are four Space Shuttle and one Soyuz missions scheduled to fly to the ISS during Expedition Two. They are:

5A.1 (STS-102, Discovery), in March 4R (Russian Soyuz), in April 6A (STS-100, Endeavour), in May 7A (STS-104, Atlantis), in June 7A.1 (STS-105, Discovery), in July

The international crew of three consisted of Commander Yury Usachev, a Russian cosmonaut; Flight Engineer James Voss a U.S. astronaut; and a U.S. astronaut and Flight Engineer Susan Helms. As a part of the STS-102 Shuttle mission, Discovery delivered the Expedition Two crew to the ISS. During their stay, the crew saw the orbital outpost increase in size and become self-sufficient. August 13, 2001 marked the end of the Expedition Two crew stay on the station.

Spacewalks

The STS-104 crew performed all spacewalks.

First spacewalk; Joint Airlock Installation

The first spacewalk focuses on airlock installation. The spacewalkers will help as Susan Helms, using the station's robotic arm, lifts the new station airlock from Atlantis' payload bay and moves it to the station's Unity module. During much of the almost seven-hour spacewalk, Jim Reilly will work from a foot platform attached to the end of the shuttle's robotic arm, operated by Janet Kavandi. After the spacewalk, crewmembers inside the Station will attach connections to the airlock to prevent thermal damage.

Second spacewalk

The second spacewalk will last about 5½ hours. The internal hatches between the shuttle and station will be closed at the end of Flight Day 6 so Atlantis' cabin pressure can be lowered in preparation for the second spacewalk. The major objective is to attach and connect an oxygen and a nitrogen tank. Susan Helms will operate the station arm to lift the tanks from the shuttle's payload bay and maneuver them to the new airlock. At the airlock, Mike Gernhardt and Jim Reilly will latch the tanks in place and connect cables and hoses.

Third spacewalk

The third spacewalk will be the first exiting through the new Space Station airlock. It may include a new protocol, developed by former commercial diver Mike Gernhardt, to purge nitrogen from the spacewalkers' bodies -- essentially exercising while breathing oxygen. Primary objective is to install the final two tanks -- one oxygen and one nitrogen -- outside the airlock.