In the Operations and Checkout Building, the Joint Airlock Module, now in vertical position, is ready to be moved into a vacuum chamber for testing. The module is the gateway from which crew members aboard the International Space Station (ISS) will enter and exit the 470-ton orbiting research facility. The airlock is a critical element of the ISS because of design differences between American and Russian spacesuits. The Joint Airlock Module is specially designed to accommodate both suits, providing a chamber where astronauts from every nation can suit up for space walks to conduct maintenance and construction work or to do science experiments outside the Station. The Space Shuttle Atlantis will carry the airlock to orbit on mission STS-104, the 10th International Space Station flight, currently targeted for liftoff in May 2001. The Shuttle crew will secure the airlock to the right side of Unity, the American-built connecting node that currently comprises one-third of the current Space Station, along with the Russian modules Zarya and Zvezda KSC-00pp1403

The Space Shuttle program was the United States government's manned launch vehicle program from 1981 to 2011, administered by NASA and officially beginning in 1972. The Space Shuttle system—composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank— carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). When its mission was complete, the orbiter would re-enter the Earth's atmosphere and lands as a glider. Although the concept had been explored since the late 1960s, the program formally commenced in 1972 and was the focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. It started with the launch of the first shuttle Columbia on April 12, 1981, on STS-1. and finished with its last mission, STS-135 flown by Atlantis, in July 2011.

Space Shuttle Atlantis was a space shuttle that was operated by NASA as part of the Space Shuttle program. It was the fourth operational shuttle built, and the last one to be built before the program was retired in 2011. Atlantis was named after the first research vessel operated by the Woods Hole Oceanographic Institution, and it made its first flight in October 1985. Over the course of its career, Atlantis completed 33 missions and spent a total of 307 days in space. Its last mission was STS-135, which was the final mission of the Space Shuttle program. Atlantis is now on display at the Kennedy Space Center Visitor Complex in Florida. Space Shuttle Atlantis (Orbiter Vehicle Designation: OV-104) was one of the four first operational orbiters in the Space Shuttle fleet of NASA, the space agency of the United States. (The other two are Discovery and Endeavour.) Atlantis was the fourth operational shuttle built. Atlantis is named after a two-masted sailing ship that operated from 1930 to 1966 for the Woods Hole Oceanographic Institute. Atlantis performed well in 25 years of service, flying 33 missions.