The final countdown: Shuttle Atlantis

The space shuttle Atlantis makes its maiden voyage on Oct. 3, 1985, for the Defense Department's STS-51-J mission. At 176,413 pounds, Atlantis is nearly 3.5 tons lighter than Columbia, which was the heaviest shuttle. Atlantis is the lightest shuttle of the remaining fleet, weighing 3 pounds less than the shuttle Endeavour (with the three main engines). Atlantis is also the last space shuttle to be retired.

Other statistics:
Length: 122.17 feet
Height: 56.58 feet
Wingspan: 78.06 feet

NASA's Magellan spacecraft is deployed from Atlantis' cargo bay in 1989 during the STS-30 mission. The Venus orbiter was the first interplanetary probe launched from a space shuttle. Later that year, Atlantis launched the Galileo probe to Jupiter.

NASA and the Russian space agency kicked off a new era in international space cooperation during the STS-71 mission in June 1995, when Atlantis docked with Russia's Mir space station for the first time. This historic photo of the linked spacecraft was taken from a Russian Soyuz capsule during a fly-around.

The space shuttle Atlantis begins the slow journey to Launch Pad 39A from the Vehicle Assembly Building at NASA's Kennedy Space Center in preparation for the launch of STS-79 in September 1996. This dramatic view, looking directly down onto the shuttle stack, was taken from the roof of the 525-foot-tall VAB.

Astronaut Shannon Lucid floats through the tunnel that connects Spacelab to Atlantis' cabin on Sept. 24, 1996. The Spacelab module rode in the shuttle's cargo bay and provided more space for scientific experiments. During this STS-79 mission, Atlantis linked up with Russia's Mir space station and brought Lucid back to Earth.

Atlantis streaks into the early morning sky from NASA's Kennedy Space Center on May 15, 1997, as seen in this long-exposure photo taken from Veterans Memorial Park in Titusville, Fla. Atlantis' 10-day STS-84 mission featured a docking with Russia's Mir space station and a crew transfer. Atlantis docked with Mir seven times before the space station was deorbited in 2001.

The space shuttle Atlantis went back to its assembly plant in Palmdale, Calif., for 10 months of refurbishment and upgrades in 1997-1998. This aerial photo shows Atlantis taking a piggyback ride back to Kennedy Space Center in Florida atop a modified Boeing 747 jet on Sept. 1, 1998.

Atlantis' upgraded cockpit gets a once-over in 1999 from engineers and executives, including Roy Bridges, Kennedy Space Center's director (seated at bottom left), as well as Laural Patrick, Joann Morgan and George Selina. The upgrades made Atlantis the most modern orbiter in the shuttle fleet, with a control system as advanced as those found on commercial jet airliners and military aircraft.

Izeal Battle, a worker from United Space Alliance, repairs heat-shield tiles on the belly of the space shuttle Atlantis in the Orbiter Processing Facility at Kennedy Space Center on Jan. 30, 2004.

Atlantis' astronauts leave their quarters at Kennedy Space Center and board the "Astrovan" for the ride out to Launch Pad 39B on Sept. 8, 2006, while gun-toting guards keep watch. A faulty fuel gauge grounded the shuttle for an extra day, but on Sept. 9 the shuttle lifted off on its STS-115 mission to the International Space Station. It marked Atlantis' first launch since 2002.

The space shuttle Atlantis rises on a pillar of cloud from Launch Pad 39B at Kennedy Space Center on Sept. 9, 2006. Atlantis delivered structural components to the International Space Station during its STS-115 mission, resuming an orbital construction project that was stopped following the 2003 Columbia tragedy.

The clouds of Earth provide a backdrop for Atlantis shortly after its departure from the International Space Station on Sept. 17, 2006.

Atlantis lands amid darkness at Kennedy Space Center in Florida on Sept. 21, 2006, bringing the STS-115 space station construction mission to a successful close.

Atlantis crew members Chris Ferguson and Dan Burbank look over their spaceship after landing at Kennedy Space Center on Sept. 21, 2006. Ferguson was slated to be Atlantis' commander for NASA's final space shuttle mission.

The space shuttle Atlantis' solid rocket boosters light up for launch on June 8, 2007, beginning a flight to the International Space Station. This STS-117 mission marked the 250th orbital human spaceflight.

NASA mission managers monitor Atlantis' liftoff from Firing Room 4 at Kennedy Space Center in Florida on Nov. 16, 2009. During the STS-129 mission, Atlantis delivered a payload platform and vital supplies to the International Space Station.

Nearly an hour after launch, contrails from the shuttle Atlantis' liftoff float above the Vehicle Assembly Building at Kennedy Space Center in Florida on June 8, 2007.

Spacewalkers Andrew Feustel and John Grunsfeld work on the Hubble Space Telescope on May 16, 2009, during Atlantis' STS-125 mission. This marked the final Hubble servicing mission.

Atlantis astronaut Mike Massimino writes notes on a checklist during the STS-125 Hubble servicing mission on May 18, 2009. During this mission, Massimino became the first astronaut to send a Twitter update from orbit: "Launch was awesome!!"

NASA astronaut Janet Kavandi leads President Barack Obama, First Lady Michelle Obama and their daughters Sasha and Malia beneath the shuttle Atlantis during a tour of the Orbiter Processing Facility at Kennedy Space Center on April 29, 2011. At the time, Atlantis was being prepared for its final flight.

Space shuttle Atlantis lifts off from Launch Pad 39A at NASA's Kennedy Space Center in Florida on July 8, 2011. The shuttle fleet's 135th and final mission, known as STS-135, brought supplies to the international space station.

Spectators watch the liftoff of Atlantis on its final mission at NASA's Kennedy Space Center in Florida on July 8, 2011.

The space shuttle Atlantis docks with the International Space Station for the last time on July 10, 2011. The shuttle delivered more than four tons of food, clothes and other supplies to keep the space station going in the post-shuttle era. NASA figures that this shipment will help keep the space station provisioned at least through the end of 2012.

This poster pays tribute to the shuttle Atlantis' quarter-century of spaceflight: Graphic elements include the International Space Station and Russia's Mir space station, the Hubble Space Telescope (which Atlantis visited during the last servicing mission) and Venus and Jupiter (which were the destinations for probes launched from Atlantis). Threaded through the design are the mission patches for each of Atlantis' flights. A copy of this tribute poster hangs in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida.

An unprecedented view of the space shuttle Atlantis, appearing like a bean sprout against clouds and city lights, on its way home, as photographed by the Expedition 28 crew of the International Space Station on July 21, 2011. Airglow over Earth can be seen in the background. The Atlantis returned to Earth marking the end of the space shuttle era when its wheels touched down for the last time at the Kennedy Space Centre. 'After serving the world for over 30 years, the space shuttle has earned its place in history. It's come to a final stop,' Atlantis commander Chris Ferguson replied.

Johnson Space Center employees Shelley Stortz, left, and Jeremy Rea, right, hold hands as they watch space shuttle Atlantis land on July 21, 2011, in Houston.

Space shuttle Atlantis lands at the Kennedy Space Center in Cape Canaveral, Florida, on July 21, 2011. The Atlantis glided home through a moonlit sky for its final landing at the Kennedy Space Center in Florida, completing a 30-year odyssey for NASA's shuttle fleet.