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Space Station 20th: Spacewalking History


John Uri |
June 4, 2020


Assembly of the International Space Station would not have been possible without the skilled work of dozens of astronauts and cosmonauts performing intricate tasks in bulky spacesuits in the harsh environment of space. Spacewalks, or extravehicular activities (EVAs), were indispensable to the assembly of station and, today, remain important to the continued maintenance of the world-class laboratory in low-Earth orbit.

Left: Aleksei Leonov during the world’s first spacewalk in March 1965. Right: Edward White during the first American EVA in June 1965.

On June 3, 1965, astronaut Edward H. White opened the hatch to the Gemini 4 capsule and, as he floated out of the cabin, became the first American spacewalker. A few weeks earlier, on March 18, Soviet cosmonaut Aleksei A. Leonov took the world’s first spacewalk as he floated out of an airlock attached to his Voskhod 2 spacecraft. Although White’s 36-minute spacewalk appeared effortless, later spacewalkers in the Gemini program found accomplishing actual work quite challenging. Because NASA considered mastering spacewalking a critical task for the Apollo Moon-landing program, astronauts and engineers expended much effort to learn the required skills. By the final flight of the Gemini program, astronaut Edwin E. “Buzz” Aldrin proved that EVAs could be productive. His training in an underwater environment to simulate spacewalking proved to be a game-changer, and the practice has been standard ever since. 

Left: Apollo 17 astronaut Harrison H. “Jack” Schmitt during a spacewalk on the lunar surface in 1972. Middle: Skylab 4 astronaut Edward G. Gibson during the final spacewalk of the Skylab program in 1974. Right: Soviet cosmonaut Georgi M. Grechko prepares for the first EVA aboard the Salyut-6 space station in 1977.

Most spacewalks during Apollo took place on the lunar surface and extended EVA durations past seven hours through upgrades to the spacesuits, or Extravehicular Mobility Units (EMUs). Spacewalks conducted aboard Skylab in the mid-1970s proved the value of spacesuited astronauts in carrying out repairs and maintenance of the space station. Indeed, the EVA to free Skylab’s jammed solar array played a key role in saving the program. Similarly, beginning in the late 1970s, Soviet — then Russian — cosmonauts using ever-improved Orlan spacesuits proved the value of spacewalks in inspecting, maintaining, repairing and augmenting space stations.

Left: STS-6 astronauts F. Story Musgrave (left) and Donald H. Peterson during the first shuttle EVA in 1983. Middle: Mir 20 crew members Sergei V. Avdeyev (left) and ESA astronaut Thomas A. Reiter in 1995. Right: STS-125 astronauts John M. Grunsfeld and Andrew J. Feustel prepare to reenter the shuttle’s airlock after the final Hubble-servicing EVA in 2009.

Spacewalks during the space shuttle era demonstrated that astronauts during EVAs could capture, repair and redeploy satellites, test future refueling of spacecraft and evaluate assembly techniques. From the first spacewalk during STS-6 in 1983 to the last non-space-station-related shuttle EVA during STS-125, the final Hubble-servicing mission in 2009, astronauts completed 52 spacewalks — 23 of them dedicated to servicing the Hubble Space Telescope in the course of five missions. Cosmonauts aboard the Mir space station made extensive use of EVAs for construction, maintenance and scientific and technology research during 79 spacewalks during the facility’s 15-year orbital lifetime. Mir also hosted the first EVA by a non-Russian crew member, Jean-Loup Chrétien from France, in 1988.

Left: Jerry Linenger during his EVA with Vasili Tsibliev outside Mir. Right: Scott Parazynski (left) and Vladimir Titov during the STS-86 EVA at Mir.

One of the stated objectives of the Shuttle-Mir Program, also known as Phase 1 of the space station, was for the United States and Russia to learn to work together as the two former adversaries prepared to jointly build and operate the space station. One arena where this was clearly demonstrated was in spacewalking. As Phase 1 progressed, astronauts living and working aboard Mir became more involved in the station’s operations, including conducting spacewalks. On April 29, 1997, Jerry M. Linenger became the first American astronaut to perform an EVA in a Russian Orlan spacesuit with his Mir 23 Commander Vasili V. Tsibliev. C. Michael Foale and David A. Wolfe added to that experience base with their Mir Orlan EVAs later that year. Foale became the first person to perform EVAs in both the U.S.  EMU and the Russian Orlan spacesuits. 

On Oct. 1, 1997, Scott E. Parazynski and Vladimir G. Titov performed the first joint U.S.-Russian EMU EVA during STS-86 while Space Shuttle Atlantis was docked to Mir. Titov was also the first non-American to conduct a shuttle-based spacewalk.


Graphic representation of the number of station EVAs in the past 22 years.

The complex assembly of space station would have been impossible without the skilled labors of spacewalking astronauts and cosmonauts. The cumulative experience of the EVAs conducted in the years prior to the start of station assembly formed a solid basis on which to build the necessary spacewalking skills. It is of interest to note that 23 years passed between Leonov’s first daring venture into open space and the first EVA at space station, during which time 171 spacewalks were completed in low-Earth orbit, on the Moon and in deep space. In the 22 years since the first station assembly spacewalk, 227 spacewalks dedicated to station have been accomplished, plus an additional 13 during space shuttle missions unrelated to the space station, four on the Russian Mir space station and one by the People’s Republic of China.

Left: STS-88 astronauts James Newman (left) and Jerry Ross perform the very first spacewalk at station in 1988. Middle: STS-96 astronaut Tammy Jernigan moves the Strela Grapple Fixture adaptor. Right: STS-106 crew members Yuri Malenchenko (left) and Ed Lu connect cables between Zarya and Zvezda during the first joint U.S.-Russian spacewalk at the space station.

From the very first assembly mission, spacewalks proved to be essential to preparing the fledgling space station for its first occupants. Astronauts Jerry L. Ross and James H. Newman conducted the first station EVA on Dec. 7, 1988, during the STS-88 mission, to connect electrical and data cables between the station’s first two modules, Zarya and Unity. Over the course of the first five shuttle assembly missions, 12 crew members conducted 10 spacewalks prior to the Expedition 1 crew taking up residency aboard the station. During STS-96, the second assembly mission in May 1999, Tamara E. “Tammy” Jernigan became the first of many women to perform an EVA at space station. Astronaut Edward T. “Ed” Lu and cosmonaut Yuri I. Malenchenko conducted the first U.S.-Russian EVA at station during the June 2000 STS-101 mission. The two connected electrical and data cables between Zarya and the newly arrived Zvezda module. Training for that spacewalk required Russian engineers to modify the Hydrolab facility at the Gagarin Cosmonaut Training Center to accommodate the U.S. EMUs. Similarly, American engineers adapted the Neutral Buoyancy Laboratory at NASA’s Johnson Space Center to allow the Expedition 1 crew to train using both the EMU and Russian Orlan spacesuit.

Left: Expedition 2 astronaut Susan Helms during the longest EVA to date. Middle: STS-100 astronaut Chris Hadfield, the first Canadian to perform a spacewalk at station. Right: Expedition 2 crew members James Voss (left) and Yuri Usachev in the hatchway to Zvezda’s Transfer Compartment, preparing for the first Russian Segment EVA.

Following the arrival of Expedition 1 crew members William M. Shepherd, Yuri P. Gidzenko and Sergei K. Krikalev aboard the space station on Nov. 2, 2000, the pace of assembly and the number of spacewalks increased significantly. Between December 2000 and April 2003, 38 astronauts and cosmonauts completed 41 EVAs, including the first staged from station itself rather than the shuttle. On March 10, 2001, Expedition 2 astronauts James S. Voss and Susan J. Helms conducted a spacewalk during STS-102 that, at eight hours and 56 minutes, still stands as the longest EVA in history. In April 2001, Canadian Space Agency astronaut Chris A. Hadfield became the first Canadian to conduct a spacewalk at the orbiting laboratory during STS-100, the flight that brought the Canadarm2 robotics system to the space station. On June 8, Voss joined Expedition 2 cosmonaut Yuri V. Usachev for the first Russian segment EVA, an internal spacewalk in Zvezda’s Transfer Compartment to prepare it for the arrival of a new module.

Left: STS-104 astronauts Michael Gernhardt emerges to begin the first EVA from the Quest Joint Airlock. Middle: Expedition 3 cosmonauts Vladimir Dezhurov (left) and Mikhail Tyurin about to begin the first EVA from the Pirs module. Right: STS-111 crew member Philippe Perrin, the first French astronaut to perform an EVA at station.

The STS-104 mission in July 2001 brought the Quest Joint Airlock to the station, providing station a standalone EVA capability with accommodations for both the U.S. EMU and Russian Orlan suits. Michael L. Gernhardt and James F. Reilly performed the first EVA from Quest on July 20. The Pirs module arrived at station on Sept. 17, providing the Russian segment with a true airlock capability. On Oct. 8, Expedition 3 cosmonauts Vladimir N. Dezhurov and Mikhail V. Tyurin staged the first EVA from Pirs. Along with American and Russian crewmates, international partners continued to play a role in spacewalking, with Philippe Perrin becoming the first astronaut from France to perform a spacewalk at statopm during the STS-111 mission in June 2002.

Left: Expedition 8 Commander Mike Foale preparing for the first “two-person” spacewalk. Middle: STS-114 astronaut Soichi Noguchi performs the first EVA for JAXA at station. Right: Expedition 13 astronaut Thomas Reiter conducts the first EVA by an ESA crew member at station.

Following the Space Shuttle Columbia accident, station spacewalks continued, but only from the Russian segment with the added complication that with the resident crew size reduced to two, the pair of spacewalking crew members left no one inside to monitor its systems. Although this posed a slightly increased risk should something go wrong, these “two-person” spacewalks proved essential during the shuttle hiatus. Expedition 8 crew members Aleksandr Y. Kaleri and Mike Foale conducted the first such EVA on Feb. 26, 2004. Foale had prior experience with the Orlan suit, as he had completed an EVA during his long-duration stay aboard Mir in 1997. The crew had to cut the spacewalk short due to Kaleri’s suit overheating and water droplets forming inside his helmet. The crew later identified the problem as a kink in the water line in his liquid cooling garment. The incident provided a preview of a more serious problem, which would occur in an EMU during an EVA more than nine years later.

On the STS-114 shuttle Return to Flight mission, Soichi Noguchi became the first astronaut from the Japan Aerospace Exploration Agency (JAXA) to conduct an EVA at station on July 30, 2005. The first ESA (European Space Agency) astronaut to perform a station spacewalk was Expedition 13 crew member Thomas A. Reiter from Germany on Aug. 3, 2006.

Left: Close-up of the tear in the solar array. Middle: STS-120 astronaut Parazynski atop the robotic arm and boom near the site of the tear. Right: Parazynski approaches the tear to effect the repair.

Although all spacewalks carry a certain amount of risk, two examples illustrate how some are riskier than others. The objectives of the STS-120 mission in October 2007 included not only the delivery of the Harmony module to station, but also the relocation of the P6 truss segment from its location atop the Z1 truss, where it had been since December 2000, to the outboard port-side truss. During the overall reconfiguration of the station’s power systems earlier in 2007, the P6’s solar arrays were rolled up.  After the crew members relocated P6 to the outboard truss, they began to unfurl the two arrays. The first array opened without incident, but with the second array nearly unfurled, the astronauts noticed a tear in a small portion of the panel and immediately halted the deployment to prevent damaging it.  Working with the crew aboard, mission managers devised a plan to have one of the astronauts essentially suture the tear in the panel. Appropriately enough, one of the two STS-120 spacewalkers, Scott E. Parazynski, was also a physician, and he put his suturing skills to good use. Attached to a portable foot restraint, Parazynski was hoisted atop not only the station’s robotic arm, but also the shuttle’s boom normally used to inspect the orbiter’s tiles — the impromptu arrangement providing just enough reach for Parazynski to successfully repair the torn array using a newly designed tool dubbed “cufflinks.” After he secured five cufflinks to the damaged panel, crew members inside the station fully extended the array as Parazynski monitored the event.

Left: Expedition 36 astronaut Luca Parmitano during EVA 23. Right: Expedition 36 crew members Karen Nyberg (left) and Fyodor Yurchikhin assist Parmitano with removing his EMU after his safe return to the airlock.

Luca S. Parmitano, the first astronaut representing the Italian Space Agency to conduct an EVA at station, and his fellow Expedition 36 crewmate Christopher J. Cassidy began U.S. EVA 23, their second EVA together, on July 16, 2013, without incident. Forty-four minutes into the spacewalk, as the two worked on their individual tasks at different locations on station, Parmitano reported feeling water at the back of his head. Mission control advised them to halt their activities as they devised a plan of action. Cassidy came to Parmitano’s side to assess the situation, at first believing that a leaking drink bag inside the suit was the source of the water. But as Parmitano indicated that the amount of water was increasing, mission control advised them to terminate the spacewalk, directing Parmitano to head back to the airlock and Cassidy to clean up any tools and then follow his crewmate back to the airlock. As Parmitano began translating back toward the airlock, the water continued to increase, migrating from the back of his head and filling his ears so he had difficulty hearing communications and, eventually, obscuring his vision and interfering with breathing. He made his way back to the airlock mostly by memory and feel and, after Cassidy joined him inside, they repressurized the module. Expedition 36 crewmates Karen L. Nyberg and Fyodor N. Yurchikhin helped Parmitano quickly remove his helmet and towel off the estimated 1 to 1.5 liters of water. Later investigation indicated that contamination on a filter caused blockage in the suit’s water separator. Although Parmitano faced a potentially life-threatening situation, his calm response, along with quick decisions by the team in mission control, resolved the crisis successfully. He later joked during an in-flight press conference that he now had “experience what it was like to be a goldfish in a fishbowl from the point of view of the goldfish.”


Left: Preparing for the first all-woman spacewalk are Expedition 61 astronauts Jessica Meir (left) and Christina Koch. Right: The latest spacewalk on station in January 2020, performed by Expedition 61 astronauts Drew Morgan (left) and Parmitano.

The Expedition 61 crew completed a record nine spacewalks between Oct. 6, 2019, and Jan. 25, 2020.  Five involved tasks to replace batteries on the P6 truss segment and three to repair the Alpha Magnetic Spectrometer (AMS), a physics experiment not originally designed for on-orbit repairs. Of note, Christina H. Koch and Jessica U. Meir conducted the third battery-replacement EVA on Oct. 18, the first all-female spacewalk in history. The pair complete two more spacewalks in January 2020. Their fellow crewmates Andrew J. “Drew” Morgan and Luca Parmitano completed the most recent spacewalk to date, the final spacewalk to repair AMS.