NASA - National Aeronautics and Space Administration

The International Space Station's robot arm moves the Quest airlock into position. Credit: NASA

Expedition 9 NASA ISS Science Officer Mike Fincke works inside Quest. Credit: NASA

The Quest Airlock is a pressurized space station module consisting of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. The airlock is the primary path for International Space Station spacewalk entry and departure for U.S. spacesuits, which are known as Extravehicular Mobility Units, or EMUs. Quest can also support the Russian Orlan spacesuit for spacewalks.

The Joint Airlock acts as a stowage area for spacewalk hardware as well as a staging area for crewmembers preparing to conduct a spacewalk. A combination of the depress pump and pressure equalization valves located within the hatches accommodate the depressurization/pressurization capability of the airlock.

The addition of the airlock permits space station-based spacewalks to be performed without major loss of environmental consumables such as air. Quest was attached to the Station on July 15, 2001, on STS-104, a mission flown by space shuttle Atlantis. Five days later, Astronauts Carl Walz and Daniel Bursch were the first to perform a spacewalk through the new airlock.

The first spacewalk to be conducted from Quest without a space shuttle present was on Feb. 20, 2002.

Quest Specifications
Length	18 feet
Diameter	13.1 feet
Mass	21,877 pounds
Launch date	July 12, 2001