STS-135 (Atlantis / final Shuttle flight)

Background

By the summer of 2011, the Space Shuttle program had been flying for three decades, surviving two catastrophic losses and carrying more than 350 individual astronaut flights across 134 missions. The decision to retire the orbiter fleet had been formalised under the Vision for Space Exploration in 2004 and reaffirmed by the Obama administration in 2010, which redirected NASA's human spaceflight ambitions toward commercial crew vehicles and, eventually, deep-space exploration. With the ISS now dependent on Russian Soyuz spacecraft for crew rotation, one final logistics flight was deemed essential: a mission to deliver a full year's worth of supplies to the station before the fleet stood down for good.

Atlantis was chosen to fly that mission, designated STS-135. Originally conceived as a contingency flight to be held in reserve in case STS-134 suffered a problem requiring rescue, it was formally manifested as a standalone mission after program managers satisfied themselves that the orbiter could be readied on schedule. Congress approved the necessary funding in late 2010. Because no rescue flight was possible — Atlantis herself was the last orbiter capable of flight — the four-person crew was sized to fit aboard a Soyuz lifeboat if an emergency stranded them at the station.

Commander Christopher Ferguson had previously commanded STS-115 and STS-126. Pilot Douglas Hurley, a Marine aviator and test pilot, would go on to command the first crewed Dragon mission a decade later. Mission specialists Sandra Magnus and Rex Walheim both brought deep ISS experience; Magnus had spent more than four months aboard the station on a previous long-duration stay.

Launch and Ascent

At the Kennedy Space Center, public anticipation for the final launch drew an estimated crowd of several hundred thousand people along the nearby causeways and beaches — an extraordinary turnout for an era in which Shuttle launches had long since become routine to many. Weather, which had threatened to scrub the attempt, ultimately cooperated.

At the moment of ignition on 8 July 2011, Atlantis lifted clear of Launch Complex 39A for the 135th and final time. The main engines and solid rocket boosters performed nominally, and approximately eight and a half minutes after liftoff — at mission elapsed time T+00:08:30 — Atlantis reached orbit, its main engines shutting down as the external tank was jettisoned. The crew, watching the tank tumble away against the black of space, knew they were the last Shuttle crew who would ever see that sight.

Operations at the International Space Station

Atlantis's primary payload was the Raffaello Multi-Purpose Logistics Module, a pressurised Italian-built container loaded with more than 4.5 tonnes of food, spare parts, science equipment, and clothing — roughly a year's worth of provisions for the station's resident crew. The docking with the ISS occurred at T+55:33:20, at which point the hatches were opened and a period of intensive cargo transfer began. Working alongside the station's Expedition 28 crew, Ferguson, Magnus, Walheim, and Hurley shifted equipment through the connecting tunnel in what amounted to one of the largest single cargo transfers the program had accomplished.

During the docked phase, Atlantis's robotic arm and the station's own Canadarm2 were used to support inspections of the orbiter's heat shield and facilitate the transfer of the Raffaello module's contents. The crew also returned a failed pump module to Earth for engineering analysis, conducted a late inspection of the thermal protection system, and participated in a farewell ceremony with the Expedition 28 crew — a moment of evident weight given the historic circumstances.

Final undocking from the station came at T+250:00:00. After the standard separation and fly-around inspection, Atlantis drew away from the complex that it had visited so many times, and the crew turned toward home.

Return and the End of an Era

With deorbit burn completed at T+305:33:20, Atlantis descended through the atmosphere on a heading toward the Shuttle Landing Facility at Kennedy Space Center in Florida. The night approach — the vehicle crossing the terminator in the predawn darkness of 21 July 2011 — was tracked by thousands who had gathered at the facility and along adjacent roads. The familiar twin sonic booms rolled across the Florida coast, and then the distinctive delta silhouette of Atlantis appeared against a dark sky, its landing lights visible as it flared for the runway.

Wheels stop came at T+306:28:00. As the orbiter rolled to a halt, Commander Ferguson's words were transmitted to Mission Control: "Mission complete, Houston." The response from the ground, and from the assembled crowds, carried the weight of thirty years of spaceflight history.

It was the 26th and final flight of Atlantis, and the 135th flight of the Space Shuttle program. The crew stepped off the orbiter to cheers from workers who had spent careers keeping the fleet flying — technicians, engineers, flight controllers, and managers for whom the moment was professional culmination and personal farewell in equal measure.

Legacy

STS-135 marked the close of a program that had defined American human spaceflight for a generation. The Space Shuttle had deployed the Hubble Space Telescope and serviced it five times; it had assembled the International Space Station piece by piece; it had carried out landmark science and commercial satellite deployments; and it had borne the weight of two national tragedies — Challenger in 1986 and Columbia in 2003 — from which the program had recovered and continued.

Atlantis was subsequently placed on display at Kennedy Space Center's Visitor Complex, where it remains one of four orbiters preserved as museum artifacts alongside Discovery, Endeavour, and the prototype Enterprise. The ISS continued operations with crews arriving aboard Soyuz spacecraft until commercial crew vehicles — vehicles whose development was partly enabled by the Shuttle program's retirement — began regular flights in 2020.

The mission demonstrated that an ending could itself be a form of achievement. In closing out thirty years of Shuttle operations with a clean, successful flight, the crew of STS-135 ensured that the program's final chapter was written as it had begun: with Atlantis, lifting off from Kennedy Space Center and returning safely to Earth.