Hubbry Logo
Extravehicular activityExtravehicular activityMain
Open search
Extravehicular activity
Community hub
Extravehicular activity
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Extravehicular activity
Extravehicular activity
Extravehicular activity
View on Wikipedia
from Wikipedia

Cosmonaut Sergey Volkov works outside the International Space Station on August 3, 2011.
Stephen Robinson riding the Canadarm2 while conducting the first in-flight repair of the Space Shuttle during STS-114 on August 3, 2005. The landmass in the backdrop is the Bari region of Somalia.

Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA includes spacewalks and lunar or planetary surface exploration (commonly known from 1969 to 1972 as moonwalks). In a stand-up EVA (SEVA), an astronaut stands through an open hatch but does not fully leave the spacecraft.[1] EVAs have been conducted by the Soviet Union/Russia, the United States, and China; astronauts from Canada, Japan, Brazil, the United Arab Emirates, and the European Space Agency have also participated in EVAs conducted by those nations.

On March 18, 1965, Alexei Leonov became the first human to perform a spacewalk, exiting the Voskhod 2 capsule for 12 minutes and 9 seconds. On July 20, 1969, Neil Armstrong became the first human to perform a moonwalk, outside his lunar lander on Apollo 11 for 2 hours and 31 minutes. In 1984, Svetlana Savitskaya became the first woman to perform a spacewalk, conducting EVA outside the Salyut 7 space station for 3 hours and 35 minutes. On the last three Moon missions, astronauts also performed deep-space EVAs on the return to Earth, to retrieve film canisters from the outside of the spacecraft. American Astronauts Pete Conrad, Joseph Kerwin, and Paul Weitz also used EVA in 1973 to repair launch damage to Skylab, the United States' first space station.

EVAs may be either tethered (the astronaut is connected to the spacecraft; oxygen and electrical power can be supplied through an umbilical cable; no propulsion is needed to return to the spacecraft), or untethered. Untethered spacewalks were only performed on three missions in 1984 using the Manned Maneuvering Unit (MMU), and on a flight test in 1994 of the Simplified Aid For EVA Rescue (SAFER), a safety device worn on tethered U.S. EVAs.

Development history

[edit]

NASA planners invented the term extravehicular activity (abbreviated with the acronym EVA) in the early 1960s for the Apollo program to land humans on the Moon, because the astronauts would leave the spacecraft to collect lunar material samples and deploy scientific experiments. To support this, and other Apollo objectives, the Gemini program was spun off to develop the capability for astronauts to work outside a two-person Earth orbiting spacecraft. However, the Soviet Union was fiercely competitive in holding the early lead it had gained in crewed spaceflight, so the Soviet Communist Party, led by Nikita Khrushchev, ordered the conversion of its single-pilot Vostok capsule into a two- or three-person craft named Voskhod, in order to compete with Gemini and Apollo.[2] The Soviets were able to launch two Voskhod capsules before U.S. was able to launch its first crewed Gemini.

The Voskhod's avionics required cooling by cabin air to prevent any kind of overheating, therefore an airlock was required for the spacewalking cosmonaut to exit and re-enter the cabin while it remained pressurized. Unusually, and by contrast, the Gemini avionics did not require air cooling, allowing the spacewalking astronaut to exit and re-enter the depressurized cabin through an open hatch. Because of this, the American and Soviet space programs developed different definitions for the duration of an EVA. The Soviet (now Russian) definition begins when the outer airlock hatch is open and the cosmonaut is in vacuum. An American EVA began when the astronaut had at least their head outside the spacecraft.[3] The U.S. has changed its EVA definition since.[4][5]

First instance

[edit]
Alexei Leonov performs the first spacewalk during Voskhod 2.

The first EVA was performed on March 18, 1965, by Soviet cosmonaut Alexei Leonov, who spent 12 minutes and 9 seconds outside the Voskhod 2 spacecraft. Carrying a white metal backpack containing 45 minutes' worth of breathing and pressurization oxygen, Leonov had no means to control his motion other than pulling on his 15.35 m (50.4 ft) tether. After the flight, he claimed this was easy, but his space suit ballooned from its internal pressure against the vacuum of space, stiffening so much that he could not activate the shutter on his chest-mounted camera.[6]

At the end of his space walk, the suit stiffening caused a more serious problem: Leonov had to re-enter the capsule through the inflatable cloth airlock, 1.2 m (3 ft 11 in) in diameter and 2.5 m (8 ft 2 in) long. He improperly entered the airlock head-first and got stuck sideways. He could not get back in without reducing the pressure in his suit, risking "the bends". This added another 12 minutes to his time in vacuum, and he was overheated by 1.8 °C (3.2 °F) from the exertion. It would be almost four years before the Soviets tried another EVA. They misrepresented to the press how difficult Leonov found it to work in weightlessness and concealed the problems encountered until after the end of the Cold War.[6][7]

Project Gemini

[edit]
Ed White performs the first American spacewalk during Gemini IV.

The first American spacewalk was performed on June 3, 1965, by Ed White from the second crewed Gemini flight, Gemini IV, for 21 minutes. White was tethered to the spacecraft, and his oxygen was supplied through a 25-foot (7.6 m) umbilical, which also carried communications and biomedical instrumentation. He was the first to control his motion in space with a Hand-Held Maneuvering Unit, which worked well but only carried enough propellant for 20 seconds. White found his tether useful for limiting his distance from the spacecraft but difficult to use for moving around, contrary to Leonov's claim.[6] However, a defect in the capsule's hatch latching mechanism caused difficulties opening and closing the hatch, which delayed the start of the EVA and put White and his crewmate at risk of not getting back to Earth alive.[8]

No EVAs were planned on the next three Gemini flights. The next EVA was planned to be made by David Scott on Gemini VIII, but that mission had to be aborted due to a critical spacecraft malfunction before the EVA could be conducted. Astronauts on the next three Gemini flights (Eugene Cernan, Michael Collins, and Richard Gordon), performed several EVAs, but none was able to successfully work for long periods outside the spacecraft without tiring and overheating. Cernan attempted but failed to test an Air Force Astronaut Maneuvering Unit which included a self-contained oxygen system.

On November 13, 1966, Edwin "Buzz" Aldrin became the first to successfully work in space without tiring during Gemini XII, the last Gemini mission. Aldrin worked outside the spacecraft for 2 hours and 6 minutes, in addition to two stand-up EVAs in the spacecraft hatch for an additional 3 hours and 24 minutes. Aldrin's interest in scuba diving inspired the use of underwater EVA training to simulate weightlessness, which has been used ever since to allow astronauts to practice techniques of avoiding wasted muscle energy.

First crew transfer

[edit]

On January 16, 1969, Soviet cosmonauts Aleksei Yeliseyev and Yevgeny Khrunov transferred from Soyuz 5 to Soyuz 4, which were docked together. This was the second Soviet EVA, and it would be almost another nine years before the Soviets performed their third.[6]

Apollo missions

[edit]
Buzz Aldrin walks on the Moon during the pioneering Apollo 11 mission in 1969.

American astronauts Neil Armstrong and Buzz Aldrin performed the first EVA on the lunar surface on July 21, 1969 (UTC), after landing their Apollo 11 Lunar Module spacecraft. This first Moon walk, using self-contained portable life support systems, lasted 2 hours and 36 minutes. A total of fifteen Moon walks were performed among six Apollo crews, including Charles "Pete" Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charles Duke, Eugene Cernan, and Harrison "Jack" Schmitt. Cernan was the last Apollo astronaut to step off the surface of the Moon.[6]

Charles Duke with a hammer on the lunar surface

Apollo 15 command module pilot Al Worden made an EVA on August 5, 1971, on the return trip from the Moon, to retrieve a film and data recording canister from the service module. He was assisted by Lunar Module Pilot James Irwin standing up in the Command Module hatch. This procedure was repeated by Ken Mattingly and Charles Duke on Apollo 16, and by Ronald Evans and Harrison Schmitt on Apollo 17.[6]

Post-Apollo

[edit]

The first EVA repairs of a spacecraft were made by Charles "Pete" Conrad, Joseph Kerwin, and Paul J. Weitz on May 26, June 7, and June 19, 1973, on the Skylab 2 mission. They rescued the functionality of the launch-damaged Skylab space station by freeing a stuck solar panel, deploying a solar heating shield, and freeing a stuck circuit breaker relay. The Skylab 2 crew made three EVAs, and a total of ten EVAs were made by the three Skylab crews.[6] They found that activities in weightlessness required about 21⁄2 times longer than on Earth because many astronauts suffered spacesickness early in their flights.[9]

After Skylab, no more EVAs were made by the United States until the advent of the Space Shuttle program in the early 1980s. In this period, the Soviets resumed EVAs, making four from the Salyut 6 and Salyut 7 space stations between December 20, 1977, and July 30, 1982.[6]

When the United States resumed EVAs on April 7, 1983, astronauts started using an Extravehicular Mobility Unit (EMU) for self-contained life support independent of the spacecraft. STS-6 was the first Space Shuttle mission during which a spacewalk was conducted. Also, for the first time, American astronauts used an airlock to enter and exit the spacecraft like the Soviets. Accordingly, the American definition of EVA start time was redefined to when the astronaut switches the EMU to battery power.[10]

Numerous EVAs were conducted during the assembly of the ISS, often using the Quest Joint Airlock, designed to support both U.S. EMUs, and Russian Orlan space suits.

By China

[edit]
Astronaut Fei Junlong performing a spacewalk on the Tiangong Space Station

China became the third country to independently carry out an EVA on September 27, 2008, during the Shenzhou 7 mission. Chinese taikonaut Zhai Zhigang completed a 22-minute spacewalk wearing the Chinese-developed Feitian space suit, with taikonaut Liu Boming wearing the Russian-derived Orlan space suit assisting him in the process. Zhai completely exited the craft, while Liu stood by at the airlock, straddling the portal.

Since 2021, China has carried out several more EVAs lasting several hours for the construction of the Tiangong space station. In December 2024 China's Cai Xuzhe and Song Lingdong set the current record for the longest EVA at 9 hours and six minutes.[11][12]

By SpaceX

[edit]

American company SpaceX conducted the first private sector-financed EVA on September 12, 2024. Entrepreneur Jared Isaacman and SpaceX engineer Sarah Gillis briefly ventured outside a Dragon capsule, for a stand-up EVA (SEVA) during the Polaris Dawn mission to conduct spacesuit mobility testing.[13] The other two crew members were exposed to the vacuum of space in the capsule, but did not leave it.[14] SpaceX plans to launch at least two more missions involving an EVA,[15] including one that involves SpaceX's still-in-development Starship launch vehicle.[16]

Milestones

[edit]

Capability milestones

[edit]


Untethered U.S. astronaut Bruce McCandless uses a manned maneuvering unit. Photo taken by Robert "Hoot" Gibson.
Capture of Intelsat VI in 1992 on STS-49. This hand-capture of a satellite is the only EVA to date to be performed by three astronauts.

Personal cumulative duration records

[edit]

National, ethnic and gender firsts

[edit]
International Space Station assembly EVA made during the STS-116 mission. Robert Curbeam (with red stripes) together with Christer Fuglesang over Cook Strait, New Zealand.
Anatoly Solovyev holds the record for time spent during spacewalks: 82+ hours over 16 separate outings, seen here performing an EVA outside Mir space station in 1997.

Commemoration

[edit]

The first spacewalk, made by Soviet cosmonaut Alexei Leonov, was commemorated in 1965 with several Eastern Bloc stamps (see Alexei Leonov#Stamps). Since the Soviet Union did not publish details of the Voskhod spacecraft at the time, the spaceship depiction in the stamps was purely fictional.

The U.S. Post Office issued a postage stamp in 1967 commemorating Ed White's first American spacewalk. The engraved image has an accurate depiction of the Gemini IV spacecraft and White's space suit.[31]

Alexei Leonov, Voskhod 2, First Spacewalk
U.S.S.R. commemorative issue of 1965
Accomplishments in Space
U.S. Commemorative Issue of 1967

Designations

[edit]

NASA "spacewalkers" during the Space Shuttle program were designated as EV-1, EV-2, EV-3 and EV-4 (assigned to mission specialists for each mission, if applicable).[32][33]

Camp-out procedure

[edit]

For EVAs from the International Space Station, NASA employed a camp-out procedure to reduce the risk of decompression sickness.[34] This was first tested by the Expedition 12 crew. During a camp-out, astronauts sleep overnight in the airlock prior to an EVA, lowering the air pressure to 10.2 psi (70 kPa), compared to the normal station pressure of 14.7 psi (101 kPa).[34] Spending a night at the lower air pressure helps flush nitrogen from the body, thereby preventing "the bends".[35][36] More recently astronauts have been using the In-Suit Light Exercise protocol rather than camp-out to prevent decompression sickness.[37][38]

See also

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Extravehicular activity

View on Grokipedia
from Grokipedia
Extravehicular activity (EVA), commonly known as a spacewalk, is any activity performed by an outside the protective confines of a while in space, requiring a specialized spacesuit to provide in the vacuum environment. The first EVA in history occurred on March 18, 1965, when Soviet cosmonaut exited the for approximately 12 minutes, marking the initial human venture into the vacuum of space. The first American EVA followed on June 3, 1965, during the mission, when H. White II spent about 20 minutes floating tethered to the capsule, using a hand-held maneuvering unit. EVAs have since become indispensable for , enabling tasks such as spacecraft repairs, satellite servicing, scientific experiments, and the assembly of large structures like the (ISS). As of October 2025, 277 EVAs have supported ISS construction and maintenance, involving both U.S. Extravehicular Mobility Units (EMUs) and Russian Orlan suits, with activities staged from airlocks like the . These operations demand meticulous planning due to inherent risks, including exposure to extreme temperatures, micrometeoroids, and the physiological challenges of microgravity, all mitigated by advanced spacesuit systems that supply oxygen, regulate pressure, and facilitate communication. Notable advancements in EVA technology continue to evolve, with NASA's Extravehicular Activity and Surface Mobility Program focusing on next-generation suits for lunar and Martian missions, emphasizing enhanced mobility, durability, and integration with robotic systems to support future deep-space endeavors.

Overview

Definition and types

Extravehicular activity (EVA), also known as a spacewalk, refers to any activity conducted outside a or planetary in the of , where astronauts exit the protective pressurized environment to perform tasks such as maintenance, exploration, or scientific experiments. This includes orbital spacewalks around and surface-based EVAs on celestial bodies like the , where individuals traverse extraterrestrial terrain while suited against harsh conditions. The term "spacewalk" gained popularity following the first such event by Soviet cosmonaut on March 18, 1965, during the mission, but formally designated these operations as extravehicular activities (EVA) starting with Edward White's excursion on June 3, 1965, aboard , to emphasize their technical scope beyond mere walking. EVAs are categorized by mobility and location. Tethered EVAs involve astronauts connected to their spacecraft or station via safety tethers and umbilicals that supply power, oxygen, and communications, ensuring restraint in microgravity and preventing drift into space. In contrast, untethered EVAs allow free-floating movement using self-contained propulsion units, such as the Manned Maneuvering Unit (MMU) first demonstrated in 1984, providing greater independence for tasks like satellite repair. Stand-up EVAs represent a limited form where an astronaut partially emerges through an open hatch—standing but not fully egressing—to observe or deploy equipment, as conducted during Apollo missions for geological surveys. Surface EVAs, exemplified by lunar traverses during the Apollo program, involve mobility across planetary surfaces in partial gravity, often supported by rovers or handheld tools for sample collection and habitat setup. A key distinction exists between EVAs and intravehicular activities (IVA), the latter encompassing work inside the pressurized cabin without exposure to , typically in lighter clothing or partial suits for routine operations. Performing any EVA demands specialized pressurized spacesuits integrated with systems to deliver breathable oxygen, regulate temperature, remove , and shield against micrometeoroids and radiation, enabling survival in the hostile .

Significance in space exploration

Extravehicular activities (EVAs) serve essential purposes in space exploration, including the repair and maintenance of , the construction of orbital structures, the conduct of scientific experiments, satellite servicing, and the preparation for future deep-space missions. These operations allow astronauts to perform tasks that cannot be accomplished from inside a , such as installing hardware or retrieving samples in the of space. For instance, the assembly of the (ISS) has relied on 277 EVAs as of October 2025 to connect modules, deploy trusses, and outfit the facility with critical systems. EVAs have made pivotal contributions to major missions by enabling on-orbit repairs and upgrades that extend the lifespan and functionality of key assets. Notable examples include the multiple servicing missions to the , where EVAs facilitated the replacement of instruments and corrective optics across five shuttle flights, restoring and enhancing its scientific output. Similarly, EVAs have supported the installation of advanced solar arrays on the ISS, such as the roll-out solar arrays (iROSAs) added in recent years to boost power generation by up to 30 percent without replacing the original arrays. These activities also test technologies for deep-space exploration, like habitat assembly techniques that inform lunar and Martian outposts. In 2024, the first commercial EVA was conducted during the SpaceX mission, marking a new era in private spaceflight capabilities. Beyond direct mission support, EVAs advance human spaceflight capabilities by demonstrating the feasibility of extended human presence in space and fostering international collaboration. They inspire public interest in science and engineering, drawing millions to follow live spacewalks and educational outreach efforts. Additionally, EVA development drives technological spin-offs, such as advanced materials from spacesuits adapted for medical applications, including isolation garments for infectious disease treatment and sensor systems for remote patient monitoring that improve healthcare accessibility. As of 2025, more than 500 EVAs have been conducted worldwide across all space programs, accumulating over 5,000 hours of extravehicular time that underscore the scale of human ingenuity in orbit.

Historical development

Early experiments and first EVAs

Prior to human spaceflight, both the Soviet Union and the United States conducted animal experiments to assess the physiological effects of high-altitude exposure and to test early pressure suit designs, laying groundwork for future extravehicular activity (EVA) capabilities. In the early 1950s, the U.S. Air Force launched successful high-altitude balloon flights carrying mammals, such as monkeys and dogs, to evaluate pressure suits and the impacts of reduced atmospheric pressure on living organisms. These tests reached altitudes exceeding 30 kilometers, simulating near-space conditions and providing data on suit integrity and animal survival in low-pressure environments. Similarly, Soviet researchers in the 1950s developed pressure suits for dogs as part of high-altitude ejection tests, exposing the animals to vacuum-like conditions in balloons and chambers to study respiratory and circulatory responses relevant to suited operations outside a spacecraft. The first uncrewed tests of EVA hardware occurred in the during the mid-1960s, focusing on the Berkut spacesuit designed for the Voskhod program. In 1964, engineers conducted trials at facilities like the TBK-60, where the Berkut suit—equipped with a life-support system—was subjected to simulated space conditions to verify mobility, pressurization, and thermal control without a human occupant. These ground-based experiments, using mannequins and instrumented dummies, identified initial issues with suit flexibility and oxygen flow, informing adjustments before crewed flights. The achieved the first crewed EVA on March 18, 1965, during the mission, when cosmonaut exited the for approximately 12 minutes. Connected to the vehicle by a 5.5-meter umbilical , Leonov demonstrated basic mobility in vacuum while tethered to the , marking humanity's initial venture outside a . The Berkut suit, pressurized at 0.27 atmospheres, supported this brief excursion, during which Leonov captured photographs and observed from orbit. The followed closely with its inaugural EVA on June 3, 1965, as part of the mission, where Edward White spent about 20 minutes outside the capsule. White used a hand-held maneuvering unit (HHMU), a pressurized oxygen thruster providing short bursts for , allowing him to float up to 6 meters from the while remaining tethered by an 8-meter umbilical. This device, weighing 1.2 kilograms, enabled controlled movements and represented an early step in untethered EVA concepts, though White relied primarily on the tether for return. Early EVAs revealed significant challenges in suit design and human factors, including stiffness, overheating, and psychological strain. Leonov's Berkut ballooned in the , increasing its volume and rigidity, which made re-entry into the narrow difficult; he had to partially depressurize the suit to regain flexibility, nearly exhausting his oxygen supply in the process. Overheating plagued both missions due to metabolic exertion in insulated suits—Leonov sweated profusely from physical effort, risking heat stress, while White's fogged from , impairing visibility and contributing to fatigue upon re-entry. Psychologically, the isolation and unexpected suit behaviors induced stress; Leonov later described moments of near-panic during re-pressurization, highlighting the mental demands of operating in an unforgiving environment without prior human precedent. These issues underscored the need for improved suit materials and to mitigate risks in subsequent operations.

Gemini and Apollo programs

The Gemini program marked a critical phase in the development of U.S. extravehicular activity (EVA) capabilities, building on earlier experiments by focusing on extended operations and equipment testing in . During in June 1966, Eugene Cernan conducted the mission's EVA, lasting 2 hours and 9 minutes, during which he evaluated the use of a hand-held maneuvering unit (HHMU) and performed tasks outside the . However, the EVA highlighted significant challenges, including severe fatigue from the physical demands of maneuvering without adequate restraints, overheating due to the suit's cooling system overload, and fogging that impaired visibility. These issues underscored the need for improved restraint systems and thermal management in future missions. Gemini 8, planned for March 1966 with as pilot, included preparations for up to three EVAs to test an and demonstrate untethered mobility, but the mission was abbreviated early due to a thruster malfunction before any EVA could occur. This preparation phase contributed valuable insights into EVA planning, including the integration of the environmental chestpack, which informed subsequent program designs. Overall, the Gemini EVAs demonstrated the feasibility of human operations but revealed limitations in duration and efficiency that directly influenced Apollo training protocols. For the , introduced innovative training methods to prepare astronauts for lunar EVAs, beginning with underwater simulations in 1966 to replicate the weightless environment and low- conditions of the . These simulations, conducted in facilities like the Neutral Buoyancy Laboratory, allowed crews to practice suited mobility, tool handling, and task sequences in a controlled setting that mimicked reduced gravity through adjustments. This approach, refined from Gemini experiences, became a cornerstone of EVA preparation, enabling realistic rehearsals of complex surface operations and reducing risks associated with unfamiliar terrain and equipment. The Apollo lunar EVAs began with in July 1969, where and conducted the first human exploration of the lunar surface, lasting approximately 2.5 hours as they deployed scientific instruments, collected samples, and tested mobility in the 1/6th gravity environment. Across Apollo missions 11 through 17 (excluding the aborted landing), astronauts performed a total of 14 lunar surface EVAs, enabling extensive geological surveys, sample collection, and experiment deployments that advanced scientific understanding of the . The longest single EVA occurred during Apollo 17's third moonwalk in December 1972, spanning 7 hours and 37 minutes, during which Eugene Cernan and traversed significant distances and gathered diverse samples from the Taurus-Littrow valley. In aggregate, these EVAs accumulated over 80 hours on the lunar surface, with a precise total of 80 hours, 44 minutes, and 8 seconds, representing a monumental achievement in human . Key technological advancements during these EVAs included the introduction of the Portable Life Support System (PLSS), a backpack unit worn by astronauts starting with to provide independent oxygen supply, , , and communications for up to 7-8 hours of untethered activity on the . The PLSS enabled greater mobility compared to umbilically tethered systems, supporting tasks like sample collection and instrument setup without constant spacecraft connection. Additionally, on , 16, and 17, crews deployed the Lunar Roving Vehicle (LRV) during the first EVA of each mission, unfolding and activating the electric-powered rover from its stowed position on the lunar module descent stage to extend traverse ranges up to 20 miles and access remote geological sites. These tools transformed lunar EVAs from short, localized outings into extended traverses, maximizing scientific returns while demonstrating reliable human-robotic integration in extraterrestrial environments.

Space Shuttle era

The marked a significant evolution in extravehicular activity (EVA), shifting focus from lunar exploration to orbital satellite maintenance, repairs, and the initial assembly of large-scale structures in . EVAs during this era, spanning from 1981 to 2011, emphasized precision tasks in microgravity, leveraging the shuttle's payload bay as a for operations. Astronauts performed these activities to deploy, retrieve, and service satellites, demonstrating the versatility of for on-orbit interventions. The inaugural Space Shuttle EVA occurred on April 7, 1983, during mission STS-6 aboard Challenger, conducted by mission specialists and Donald Peterson. Lasting approximately 4 hours and 17 minutes, this untethered spacewalk tested the shuttle's airlock and payload bay mobility, marking the first U.S. EVA since the missions a decade earlier. The activity involved evaluating the new (EMU) spacesuit, which replaced modified versions of the Apollo-era A7L suit to better accommodate shuttle-specific requirements like repeated use and modular sizing. Developed in the late 1970s by under contract, the EMU provided enhanced mobility through a hard upper torso and semi-rigid design, supporting up to 8 hours of independent via its portable backpack system. A key innovation in shuttle EVAs was the (MMU), a nitrogen-propelled backpack enabling untethered astronaut flight. First demonstrated on in February 1984 by , who traveled up to 100 meters from Challenger without safety tethers, the MMU allowed precise positioning for satellite inspections and retrievals. Its final operational use came during in November 1984, where astronauts Joseph Allen and Dale Gardner successfully captured and secured two malfunctioning satellites, Palapa B-2 and Westar 6, using the device for approach and stabilization. Although retired after four missions due to safety concerns over potential propellant depletion, the MMU exemplified early advancements in astronaut autonomy during EVAs. Prominent shuttle EVAs included the servicing of the on in December 1993, where the crew of Endeavour executed five back-to-back spacewalks over five days. These EVAs, totaling more than 35 hours, involved installing corrective optics, replacing solar arrays, and upgrading instruments to address the telescope's flawed primary mirror, restoring its scientific productivity. Another milestone was in December 1998, the first assembly mission for the (ISS), during which three EVAs connected the U.S.-built Unity node to the Russian Zarya module and prepared docking ports. These 21-hour efforts laid the foundational framework for subsequent station construction. Over the program's lifespan, crews conducted 158 EVAs, with the majority supporting satellite operations and contributing approximately 80% of the assembly tasks for the ISS through hardware installation and outfitting. This extensive EVA experience refined procedures for complex orbital construction, influencing future architectures.

Mir and early ISS

Extravehicular activities on the Soviet space station began shortly after its core module launch in February 1986, with the first EVA conducted in December 1986 by cosmonauts Leonid Kizim and Vladimir Solovyov during the mission, focusing on external inspections and equipment testing. Over the station's 15-year operational life, a total of 78 two-person EVAs were performed by 36 male cosmonauts, totaling approximately 358 hours of extravehicular time and supporting module additions, repairs, and scientific experiments. Cosmonaut set records with 16 EVAs, accumulating 77 hours and 46 minutes, primarily using the spacesuit for tasks like solar array deployments and structural reinforcements. The spacesuit, introduced in the late 1970s as a semi-rigid system for Soviet EVAs, became the standard for operations starting in the 1980s, featuring a backpack life support unit and improved mobility over earlier soft suits for prolonged station-based work. Its design allowed cosmonauts to perform complex tasks, such as the 1988 EVA by French cosmonaut Jean-Loup Chrétien—the first non-Soviet spacewalk from —installing the RAPAN spectrometer on the Kvant-1 module. These EVAs highlighted the suit's reliability in microgravity, though early missions faced issues with thermal regulation during extended exposures. International collaboration advanced with the first U.S. spacewalk at in 1996 during STS-76, when astronauts Linda Godwin and Michael Clifford conducted a 6-hour EVA to test compatibility and . This paved the way for subsequent joint EVAs, enabling shared procedures for future station work despite initial language and protocol differences between and . Transitioning to the (ISS), early assembly EVAs commenced with in December 1998, where astronauts Jerry Ross and James Newman completed three spacewalks to attach the U.S.-built Unity node to the Russian Zarya module, establishing the station's foundational structure after Zarya's November 1998 launch. Expeditions 1 through 6 (2000–2002) involved 41 EVAs by international crews, integrating the Zvezda service module in July 2000 via , where Edward Lu and connected power and data cables during their spacewalk. These activities, blending Extravehicular Mobility Units with suits, focused on outfitting systems and preparing for permanent habitation. Challenges in Mir and early ISS EVAs included elevated radiation exposure during unshielded spacewalks, with cosmonauts and astronauts receiving doses up to 10 times higher than intra-station levels, necessitating strict monitoring to limit cumulative risks. Coordination between and required harmonizing training protocols and real-time communication, as differing operational philosophies occasionally led to delays in joint tasks, though bilateral agreements ensured execution.

Modern ISS EVAs

Following the completion of the core (ISS) structure in the early 2000s, extravehicular activities (EVAs) shifted toward maintenance, upgrades, and scientific installations, marking the mature operational phase of the station from 2003 onward. These EVAs, primarily conducted by and crews using the Quest and Pirs/Poisk airlocks, respectively, supported enhancements to power systems, laboratory modules, and experimental payloads, ensuring the ISS's longevity and research capabilities. By this period, procedures had evolved to emphasize efficiency, with EVAs often lasting 6 to 8 hours and focusing on tasks that could not be achieved robotically. A notable example of international collaboration occurred during NASA's mission in February 2008, when astronauts Rex Walheim and Stanley Love performed EVA-1 to assist in the installation of the European Space Agency's Columbus laboratory module to the node, including the connection of power and cables after robotic berthing. Similarly, in May 2011, during , astronauts Mark and executed multiple EVAs to install the Alpha Magnetic Spectrometer-02 (AMS-02) particle physics detector on the ISS's Destiny module, securing it with bolts and umbilicals to enable cosmic ray observations for and research. Solar array maintenance dominated EVAs in the 2000s and 2010s; for instance, in November 2007 during , Scott Parazynski and Douglas Wheelock repaired a 10-meter tear in the P6 solar array using improvised and wire ties, restoring critical power generation without fully retracting the damaged panels. Later, in 2013, Expedition 35 crew members and conducted EVAs to lubricate the starboard Solar Alpha Rotary Joint (SARJ), addressing bearing degradation that had reduced power output by up to 25 percent. Russian contributions to modern ISS EVAs included installations supporting the Roscosmos segment, such as the 2009 Expedition 21 EVA by cosmonauts Fyodor Yurchikhin and Oleg Kotov to prepare the Poisk mini-research module for docking, involving antenna deployments and cable routing from the Pirs airlock. In 2010, Expedition 23 cosmonauts Oleg Kotov and Alexander Skvortsov performed an EVA to connect the newly docked Rassvet module to the Zarya functional cargo block, installing electrical and communication lines to expand docking ports and storage capacity. These activities, conducted in spacesuits, complemented U.S. efforts by focusing on the , with EVAs often prioritizing structural integrity and propulsion system checks. Recent developments from 2023 to 2025 centered on power system enhancements through the Installation of Roll-Out Solar Arrays (iROSA) program, which aimed to augment the original solar arrays' output by 20-30 percent to support increased electrical demands. In June 2023, NASA astronauts Stephen Bowen and Warren Hoburg completed two EVAs (U.S. EVA 87 and 88) to deploy and secure the sixth iROSA on the 1A power channel of the starboard truss, involving robotic arm assistance and manual pinning. The program paused in June 2024 after U.S. EVA 90 was aborted early due to a water leak in the Extravehicular Mobility Unit (EMU) cooling umbilical on astronaut Tracy Dyson's suit, leading to a six-month hiatus for suit inspections and repairs. Operations resumed in January 2025 with U.S. EVA 91, where Nick Hague and Suni Williams replaced a rate gyro assembly and conducted X-band antenna repairs, followed by additional iROSA installations later that year to complete the upgrades. By November 2025, the ISS had hosted over 280 EVAs since its inception, with and sharing duties roughly equally— conducting about 60 percent from the Quest and the remainder from Poisk—totaling more than 1,800 hours of extravehicular time. This collaborative framework has sustained the station's operations amid aging infrastructure. Looking ahead, is preparing for the transition to commercial spacesuits, with Space's AxEMU design contracted to replace the legacy by the early 2030s, offering improved mobility and thermal regulation for continued ISS until deorbit.

Chinese space program

China's involvement in extravehicular activity (EVA) began with the Shenzhou 7 mission on September 27, 2008, when astronaut Zhai Zhigang performed the nation's first spacewalk, lasting approximately 20 minutes outside the spacecraft at an altitude of about 340 kilometers. This milestone made China the third country to conduct an EVA, following the Soviet Union and the United States, and demonstrated the maturity of its human spaceflight capabilities. The Feitian extravehicular spacesuit, developed by the China Manned Space Engineering Office starting in the early 2000s, has been the standard for all Chinese EVAs since its debut on Shenzhou 7. Drawing brief inspiration from Soviet Orlan suits for its semi-rigid design and life support systems, the Feitian suit provides mobility, thermal protection, and up to 8 hours of standalone operation, with second-generation models extending in-orbit service life to three years and supporting over 15 uses per suit. These suits have enabled increasingly complex tasks, including equipment transfers and structural modifications, while adhering to China's self-reliant engineering approach. EVAs expanded significantly with the , beginning with the mission in November 2021, when and conducted the first station-based spacewalk, lasting 6 hours and 13 minutes to test suit functionality and integration. By 2025, had completed over 20 EVAs, evolving from capability demonstrations to maintenance and expansion operations. Key achievements include the installation of a 7-meter on the during and subsequent expansions to airlocks on the Wentian and Mengtian modules for improved extravehicular access. Notable recent EVAs highlight ongoing enhancements to Tiangong's resilience. During Shenzhou 18 in July 2024, astronauts and Li Cong performed the 16th national spacewalk, a 7-hour activity focused on installing debris shielding panels on the to protect against micrometeoroids and orbital junk. In June 2025, the Shenzhou 20 crew—Chen Dong and Chen Zhongrui—completed their second EVA, a 6.5-hour operation to further fortify station structures and integrate new support systems. An August 2025 EVA by the same crew advanced airlock fortifications, reinforcing entry points and external cabling for long-term habitability. These activities underscore China's independent space program, developed in response to U.S. restrictions under the that barred collaboration with the since 2011, fostering indigenous technologies like the Feitian suits and Tiangong's modular design. By prioritizing self-reliance, China has achieved a cumulative EVA duration exceeding 100 hours by mid-2025, supporting ambitions for sustained orbital presence and future lunar missions.

Commercial spaceflight

The emergence of commercial extravehicular activity (EVA) began in the with private companies exploring , such as Virgin Galactic's test flights of , which demonstrated pressure suits and high-altitude operations but did not involve full EVAs due to the short-duration profiles. These efforts marked initial involvement in technologies, focusing on safety and environmental exposure testing without transitioning to orbital or vacuum-based activities. SpaceX advanced commercial EVA capabilities in the 2020s, starting with the introduction of intravehicular activity (IVA) suits for Crew Dragon missions, debuted during the Demo-2 flight in May 2020, which provided pressure protection and mobility for crew inside the spacecraft. A key milestone came with the mission, launched on September 10, 2024, where commander and mission specialist conducted the first commercial spacewalk on September 12—a stand-up EVA from the Crew Dragon lasting 1 hour and 46 minutes, during which they tested suit performance in vacuum conditions at an altitude of approximately 700 km. This event represented the first EVA without government astronauts, validating non-NASA operations in . The EVA suit used in , evolved from the IVA design, was developed in just 2.5 years and featured enhanced mobility through novel joint designs and materials, a helmet-mounted heads-up display (HUD) for real-time suit metrics and mission timing, integrated cameras, and improved thermal management for exposure. These innovations prioritized scalability and manufacturability, aiming for to support future long-duration missions beyond government programs. Looking ahead, plans to enable private astronauts to participate in EVAs on the as part of missions starting in 2025, leveraging their contract for low-Earth orbit suit development and certification to support commercial operations. is pursuing orbital capabilities through its vehicle, with intentions to incorporate EVA technologies in future private missions to expand commercial access to activities. Overall, these commercial EVAs are driving down costs through reusable designs and private funding while accelerating innovation in suit technology and procedures, fostering a more diverse for independent of traditional government-led efforts.

Equipment

Spacesuits

Spacesuits are essential personal protective systems for extravehicular activity (EVA), providing pressure containment, thermal regulation, mobility, and in the vacuum of space. Early designs focused on basic pressurization and short-duration operations, evolving from soft, inflatable suits to more rigid, modular systems capable of extended EVAs. These suits must withstand extreme temperatures ranging from -250°F to 250°F, impacts, and while allowing astronauts to perform complex tasks. The Soviet Berkut suit, introduced in 1965 for the Voskhod 2 mission, was an early EVA design modified from the Vostok Sokol suit, featuring an inflatable structure for flexibility but plagued by cooling system inadequacies that caused overheating during the first spacewalk by Alexei Leonov. In the United States, the G4C suit, developed by the David Clark Company for the Gemini program and first used in 1965, improved upon Mercury-era designs with enhanced comfort, a breathing and cooling hose connected via an umbilical, and better forward-bending mobility through a chest-mounted strap, enabling the first American EVA on Gemini 4. The Apollo A7L suit, deployed from 1969, represented a major advancement with its multi-layered thermal micrometeoroid garment for protection against lunar conditions, including dust abrasion, and an integrated Portable Life Support System (PLSS) backpack that provided independent oxygen, cooling, and CO2 removal for up to 7-8 hours without umbilicals. NASA's Extravehicular Mobility Unit (EMU), operational since the 1980s for Space Shuttle and International Space Station (ISS) EVAs, is a semi-rigid, two-piece suit pressurized to 4.3 psia, supporting up to 8 hours of activity with a PLSS for oxygen, thermal control, and communications. It includes the Simplified Aid for EVA Rescue (SAFER) jetpack for self-rescue in case of tether failure. The Russian Orlan series, semi-rigid suits first used in 1977 on Salyut 6 and refined through versions like Orlan-M and Orlan-MKS since the 1980s, offer up to 9 hours of EVA time with a rear-entry design for easier donning, supporting operations on Mir, the ISS, and similar stations. China's Feitian suit, debuting in 2008 during Shenzhou 7, adopts a hybrid design inspired by Orlan but with indigenous flexible limb joints for improved mobility across user heights of 1.60 to 1.80 meters, enabling EVAs on Tiangong. In the commercial era, SpaceX's Polaris suit, tested in 2024 for the mission, features integrated liquid cooling, a 3D-printed with anti-glare visor and heads-up display (HUD) for real-time , and built-in cameras for enhanced during private EVAs. Space's AxEMU, developed for the Artemis III lunar mission now scheduled for no earlier than mid-2027, emphasizes lunar-specific mobility with articulated knees for kneeling and working on uneven surfaces, advanced thermal protection, and modular components building on prototypes. Common components across EVA spacesuits include a pressure bladder, typically made of urethane-coated to maintain internal at around 4.3 psi against the ; a (LCVG) with embedded tubes circulating water to regulate body temperature; and helmets with multi-layered visors for UV protection, anti-fogging, and visibility. These elements ensure physiological safety and operational efficiency, with designs continually refined for longer durations and diverse environments.

Tools and support systems

Manual tools used during extravehicular activities (EVAs) include specialized devices designed for precision tasks in the harsh space environment. The Pistol Grip Tool (PGT), a battery-powered, microprocessor-controlled with a 3/8-inch drive, enables astronauts to apply torque to mechanical interfaces on structures like the and the (ISS), supporting repairs and assembly without requiring physical strain from manual tightening. Tether kits, consisting of and equipment tethers with hooks, secure astronauts and tools to the to prevent drift in microgravity, with each crewmember equipped with two tethers at the waist for continuous attachment during translation. Sample collection bags, lightweight and sealable containers, facilitate the gathering and storage of small materials or for scientific analysis, often clipped to suits or carriers for easy access. Mobility aids enhance navigation and safety outside the . The (SAFER), a self-contained with 24 thrusters, provides controlled for untethered movement, allowing an to return to the station if detached; first tested in 1994 during STS-64, it serves as a successor to the earlier (MMU) by offering simpler, emergency-only functionality without the need for complex piloting. Support systems ensure operational efficiency and resource management during EVAs. Airlock depressurization in the ISS , which includes crewlock and equipment lock compartments, prepares astronauts for exposure by gradually venting atmosphere to , typically taking 30-40 minutes to reach EVA conditions. EVA carts, such as the Tool Caddy, transport and organize tools and equipment from the airlock to worksites, mounted on the station's or carried by for tasks like hardware reconfiguration. Umbilical tethers supply supplemental power and cooling to suits or tools when needed, though modern EVAs primarily rely on self-contained systems; these connect via the Service and Cooling Umbilical (SCU) for pre-EVA checks or extended operations. Robotic systems augment human capabilities by handling heavy payloads and intricate manipulations. Canadarm2, the Space Station Remote Manipulator System (SSRMS) operational since 2001, is a 17-meter articulated arm that supports EVA tasks by positioning astronauts, moving equipment up to 116,000 kg, and berthing spacecraft, often used in tandem with the Mobile Base System for traversal along the ISS truss. Dextre, or the Special Purpose Dexterous Manipulator (SPDM), deployed in 2008, features two 3.5-meter arms that grip and operate tools like wire cutters or socket wrenches, enabling maintenance such as battery replacements without crew exposure to risks. The Tianhe core module's robotic arm, a 10-meter manipulator launched in 2021 as part of China's , assists EVAs by maneuvering astronauts and payloads, as demonstrated during the Shenzhou-12 mission for station construction support. Recent advancements include specialized tools for iROSA (ISS Roll-Out Solar Array) installations from 2021 to 2025, where astronauts used modified PGTs and torque multipliers to secure array brackets with eight bolts per unit on the ISS , upgrading power generation capacity by over 20 kilowatts per array without interrupting station operations.

Procedures and training

Preparation and denitrogenation

Preparation for extravehicular activity (EVA) prioritizes astronaut safety through denitrogenation, the process of purging nitrogen from body tissues to mitigate , commonly known as the bends, which can occur when transitioning from higher cabin pressures to the lower pressure of a spacesuit. Astronauts achieve this by 100% pure oxygen, typically for durations exceeding 24 hours in early protocols, though modern methods incorporate exercise or reduced-pressure exposure to shorten the timeline while maintaining safety margins. NASA's camp-out procedure, a key element of denitrogenation, requires the EVA crew to spend approximately eight hours overnight in the Quest Joint Airlock pressurized to 10.2 psi (70 kPa), initiating nitrogen washout in a controlled environment while allowing the rest of the crew to continue station operations. This approach originated as a time-efficient alternative during the Space Shuttle era and became the standard for International Space Station (ISS) EVAs starting in September 2006, enabling over 140 person-EVAs without reported decompression sickness incidents by 2010. Once denitrogenation is underway via camp-out, the suit-up process commences directly in the to minimize contamination risks and streamline egress. Crew assistants, often the non-EVA crew members, aid in donning the (EMU) by first fitting the , followed by the communications carrier assembly, maximum absorption garment, and the full suit components including the lower torso assembly and hard upper torso. With suits donned, the EVA crew performs pressurization to 4.3 psi, conducts integral leak checks using soap bubble tests on seals and joints, and verifies communication systems and biomedical telemetry before final mask prebreathe of pure oxygen for about 50 minutes. Astronaut training for these preparation phases emphasizes procedural proficiency and hazard recognition through simulations at NASA's Neutral Buoyancy Laboratory (NBL), a 40-foot-deep, 202-foot-long pool filled with 6.2 million gallons of water where suited trainees experience near-weightlessness to rehearse donning, leak checks, and operations. Complementing NBL sessions, (VR) training in the Virtual Reality Laboratory allows immersive practice of task-specific sequences, such as suit interface checks and communication protocols, using hardware-in-the-loop systems for realistic feedback without physical strain. International protocols vary to accommodate different spacesuit designs; for Russia's suits, preparation occurs in the Poisk with a condensed denitrogenation of roughly two hours of pure oxygen , enabled by the suit's higher operating of 5.8 psi (40 kPa), which reduces the decompression gradient compared to NASA's EMU.

Execution of EVA

Once the airlock is fully depressurized, the lead extravehicular crewmember (EV1) initiates egress by opening the outer hatch and exiting the on the , followed closely by the second crewmember (EV2) to maintain visual contact and coordination. Upon exiting, both crewmembers immediately attach their tethers to designated points on the or adjacent to prevent uncontrolled drift in microgravity. Initial station checks are then conducted, including verification of suit mobility, primary and secondary oxygen systems, and environmental sensors, ensuring all systems are nominal before proceeding to tasks. Task performance during the EVA involves controlled translation along the station's truss and module structures using handrails, foot restraint platforms, and occasionally the Simplified Aid for EVA Rescue (SAFER) jetpack for untethered movement if required. Crewmembers deploy tools from integrated caddies or portable carriers, such as the pistol grip tool for bolt tightening or cable cutters for routing and securing electrical harnesses, executing repairs or installations with precision to minimize time outside. These activities prioritize efficiency, with EV1 typically leading complex maneuvers while EV2 provides support, such as holding components or photographing work sites for documentation. Communication is maintained continuously between the extravehicular crew, the intravehicular crewmember (IV) monitoring from inside the station, and ground control at NASA's via the S-band system, which relays voice, , and video data in real time. This setup allows for immediate procedure adjustments, task confirmations, and troubleshooting, with the IV serving as a direct liaison to relay instructions or warnings. Contingency procedures are integral to EVA execution; for instance, if a tool is lost, the crew reports its description, location, and potential hazard to control, then assesses whether to improvise with available alternatives or abort the affected task to avoid risks. Emergency return protocols dictate an immediate ingress to the if critical issues arise, such as suit leaks or power failures, with the EV2 assisting the EV1 if needed and the IV preparing the for repressurization. EVA duration is managed to typically last 6 to 8 hours, beginning from hatch opening and ending at ingress, with ongoing monitoring of crew fatigue through verbal reports and biometric to ensure operational and prevent overexertion.

Post-EVA activities

Upon completing the extravehicular tasks, astronauts initiate ingress by returning to the through the outer hatch, a process that typically takes about 15 minutes. Once inside, the outer hatch is secured, and the is repressurized to match the spacecraft's cabin pressure, requiring approximately another 15 minutes to equalize safely and prevent decompression issues. Following repressurization, the crew enters the habitable volume, where suit doffing begins; this involves disconnecting systems, removing the (EMU) components, and stowing items like the SAFER jetpack, altogether spanning around 25 minutes. Medical checks commence immediately after doffing to monitor for and physiological stress. The Crew Medical Officer conducts evaluations within 24 hours of suit removal, including assessment (temperature, blood pressure, respiration), ear examinations for , eye checks for pressure-related effects, and neurological reviews; blood draws may be performed to analyze gas bubble formation indicative of decompression. Hydration recovery is prioritized through fluid intake protocols to counteract from sweat loss during the EVA. Debrief sessions follow medical evaluations, lasting 90 to 105 minutes as part of overall post-EVA processing. These involve the EVA crew reviewing tasks with onboard team members and ground control via audio logs and telemetry data, discussing performance, anomalies, and to refine future operations; for instance, missions emphasize assessing crew autonomy, decision protocols, and integration of science inputs during debriefs. Issues encountered, such as tool functionality or communication delays, are logged for procedural updates. Equipment maintenance is conducted promptly to ensure readiness for subsequent EVAs. Spacesuits undergo to remove from sweat and , to eliminate particulates, contaminants, and metabolic wastes like or topical residues using compatible materials, and comprehensive checkouts lasting 115 to 185 minutes. Tools are sterilized, inspected for damage, and stowed, while the is cleaned of ; consumables replenishment, such as and , takes 60 to 120 minutes. To address EVA-induced fatigue, crewmembers enter a readaptation phase with dedicated rest periods, typically avoiding back-to-back EVAs and enforcing a minimum of 4 to 5 days between outings on the . This recovery time, often 24 to 48 hours of reduced activity initially, allows for physical recuperation from metabolic demands and , with monitoring to prevent overexertion.

Risks and safety measures

Physiological hazards

Extravehicular activity (EVA) exposes astronauts to (), a condition arising from the formation of bubbles in tissues and when transitioning from higher to lower pressure environments if pre-breathing protocols are insufficient to eliminate dissolved inert gases. This risk is particularly acute during EVAs, where the suit pressure is maintained at about 4.3 psi, roughly one-third of sea-level , potentially leading to symptoms such as joint pain, numbness, or more severe neurological effects if bubbles embolize. studies have documented DCS incidence rates of around 17% in simulated EVA exposures, with precordial Doppler detecting venous gas emboli in up to 42% of cases, underscoring the need for rigorous denitrogenation to mitigate bubble formation. Radiation exposure during EVAs is significantly elevated compared to intra-vehicular activities due to the lack of spacecraft shielding against solar and galactic s, resulting in doses that can be 2 to 5 times higher per hour. Astronauts face increased risks of cancer, cataracts, and damage from , with 's career exposure limits set to constrain the risk of exposure-induced fatal cancer to no more than 3% above baseline for the general population. For context, a single 6-hour EVA might deliver 1-5 mSv, contributing notably to lifetime dose limits, especially during when cosmic ray flux peaks. Exposure to the vacuum of space, if a suit breach occurs, induces , where the low pressure causes bodily fluids to vaporize and form gas bubbles in tissues, leading to swelling, particularly in the skin and mucous membranes. This process, combined with rapid hypoxia from oxygen deprivation, can cause unconsciousness within 10-15 seconds and death within 1-2 minutes without intervention, as the lungs expel air and saliva begins to boil at body temperature. Historical vacuum chamber tests, including simulations, have shown that unprotected exposure above 63,000 feet altitude triggers , with survivors of brief exposures reporting severe pain and vision loss from ruptured blood vessels in the eyes. Microgravity during EVAs exacerbates physiological challenges, including (SAS), which affects up to 70% of astronauts with symptoms like , , and disorientation due to conflicting sensory inputs from the . Prolonged microgravity also accelerates bone mineral density loss at rates of 1-2% per month in bones, increasing fracture risk, while spaceflight-associated neuro-ocular syndrome (SANS) causes vision impairment in approximately 70% of long-duration mission astronauts through changes and from cephalic fluid shifts. These effects compound during EVAs, where physical exertion in zero gravity heightens fatigue and cardiovascular strain. Thermal extremes in the pose additional hazards, with surface temperatures fluctuating from -250°F (-157°C) in shadow to +250°F (121°C) in direct due to the absence of atmospheric conduction and . During EVAs in , astronauts can experience rapid temperature swings as they move between sunlit and shadowed regions, potentially leading to or if thermal regulation fails, though suits are designed to maintain internal comfort. These extremes stress the body's thermoregulatory systems, increasing metabolic demands and risks during physical tasks.

Technical risks and incidents

Extravehicular activities (EVAs) involve significant technical risks stemming from equipment malfunctions and harsh space environments, which can jeopardize astronaut safety and mission objectives. One early example of suit failure occurred during the 1965 mission, when cosmonaut Alexei Leonov's Berkut spacesuit inflated in the vacuum of space, reducing its flexibility and complicating re-entry into the ; Leonov had to manually vent excess pressure from the suit to restore mobility. More recent issues with the (EMU) have included leaks in the cooling system, such as during U.S. EVA 90 on June 24, 2024, when a leak in astronaut Tracy C. Dyson's suit service and cooling umbilical unit caused to spray and freeze, leading to mission termination after 31 minutes and a subsequent hiatus in U.S. segment spacewalks until January 2025. Tether failures pose additional hazards by risking uncontrolled drift into space, though astronaut tethers are designed with redundancies like the (SAFER) jetpack as a backup. Tools and equipment losses during EVAs highlight this vulnerability; for instance, during Space Shuttle mission in 2007, micrometeoroid impacts were noted on EVA tools, underscoring the potential for tether-related detachment in dynamic orbital conditions. Notable incidents illustrate these risks in action. In 2013, during U.S. EVA 23, Italian astronaut experienced a helmet intrusion of approximately 1.5 liters of water from a blocked fan motor in his EMU's cooling loop, which accumulated behind his head, impaired his vision, and nearly caused drowning before the EVA was aborted after 43 minutes. A more recent scrub occurred on June 13, 2024, when U.S. EVA 90 preparations were halted due to spacesuit discomfort reported by astronaut , preventing the planned activities with Tracy C. Dyson. Environmental threats further compound technical challenges. and orbital debris punctures remain rare for spacesuits, with no documented cases of rapid depressurization during EVAs, thanks to multi-layer thermal garments; however, the risk persists, as impacts can degrade suit integrity over multiple outings. Solar flares can interrupt EVAs by elevating levels to unavoidable hazards for exposed astronauts, prompting mission controllers to monitor forecasts and potentially curtail activities during severe events. In response to these incidents, safety measures have evolved with enhanced redundancies, such as improved water separation systems and backup cooling loops in following the 2013 and 2024 leaks. By 2025, implemented upgrades to aging suits, including better maintenance protocols and integration of advanced pressure garments, enabling resumption of spacewalks in January 2025 while transitioning toward next-generation designs like the ; no major incidents have been reported as of November 2025.

Milestones and records

Technical milestones

The development of extravehicular activity (EVA) technology has been marked by significant engineering advancements that enhanced astronaut mobility, endurance, and operational efficiency in space. One pivotal milestone was the first untethered EVA, achieved by astronaut during the mission on February 7, 1984, using the (MMU), a nitrogen-propelled that allowed independent propulsion and precise control without tethers to the ; this 5-hour, 55-minute activity demonstrated unprecedented freedom of movement, reaching up to 100 meters from the spacecraft. Advancements in suit design and systems enabled longer-duration EVAs, exemplified by the record-setting spacewalk of James Voss and on March 11, 2001, during ISS Expedition 2, which lasted 8 hours and 56 minutes as they installed struts and handrails on the station's exterior to prepare for the Destiny laboratory module. This achievement highlighted improvements in the (EMU) suit's thermal regulation and oxygen supply, allowing sustained productivity in microgravity without the fatigue limitations of earlier designs. In 2024, the mission pushed the boundaries of altitude and commercial involvement with the first private EVA following a peak mission altitude of approximately 1,400 km above Earth but conducted at about 700 km, by civilian astronauts and from the Resilience capsule; this 1 hour and 46 minute activity, supported by custom EVA suits, marked the highest-altitude human spacewalk since the mission in 1966 and validated untethered procedures in a radiation-heavy environment beyond . Robotic assistance has further revolutionized EVA efficiency by reducing astronaut exposure to hazards and enabling complex tasks. The first operational support using Dextre, the Special Purpose Dexterous Manipulator on the ISS, occurred during in March 2008, where astronauts installed and tested the robot's dual arms during multiple EVAs to perform fine maintenance on station components, minimizing the need for human intervention in high-risk areas. In a parallel development, China's saw its inaugural robotic arm-assisted EVA on November 7, 2021, during the mission, when astronauts and used the 10-meter manipulator to install equipment and cameras, showcasing integrated human-robotic coordination for station expansion. Spacesuit mobility has evolved dramatically from the rigid, limited-range designs of the , such as the Gemini G3C suit with its straight-jointed shoulders restricting arm movement to about 90 degrees, to modern prototypes emphasizing flexibility and dexterity. By 2025, Space's AxEMU suits for NASA's feature soft-material joints and articulated shoulders providing over 180 degrees of motion, tested in neutral buoyancy labs to simulate lunar gravity, thereby enhancing task performance for extended surface operations.

Duration and participation records

The record for the most cumulative time spent on extravehicular activities is held by Russian cosmonaut , who completed 16 EVAs totaling 82 hours and 22 minutes during missions in the late 1980s and 1990s. This remains the overall record as of 2025. Among U.S. astronauts, Michael Lopez-Alegria holds the national lead with 10 EVAs and 67 hours 40 minutes accumulated across Shuttle and ISS missions in the early 2000s. For women, astronaut set a previous benchmark in the 2000s with 10 EVAs and 60 hours 21 minutes, a record later surpassed in 2025 by , who reached 62 hours 6 minutes over 9 EVAs.
AstronautAgencyNumber of EVAsTotal TimePeriod
1682h 22m1988–1997
Michael Lopez-Alegria1067h 40m1995–2007
1060h 21m2002–2017
962h 6m2006–2025
Single-mission records highlight the intensity of specific operations. The lunar mission in 1972 achieved the longest total surface EVA time for a single flight, with three EVAs summing 22 hours 4 minutes conducted by Eugene Cernan and . On the , Expedition 13 in 2006 featured three EVAs totaling over 20 hours, involving crew members Pavel Vinogradov, Jeffrey Williams, and Thomas Reiter to install equipment and prepare for future assembly tasks. As of 2025, more than 260 unique individuals from 12 nations have performed EVAs, reflecting broad international collaboration on programs like the ISS and 's Tiangong station. Among them, 23 women have conducted spacewalks, underscoring gradual progress in gender representation during these high-risk activities. Nationally, the leads in total EVA hours with approximately 4,300 accumulated as of 2024 since the across Gemini, Apollo, Shuttle, and ISS missions. follows with about 1,500 hours as of 2024, primarily from Salyut, , and ISS operations since the 1970s. has logged roughly 100 hours as of 2024 since its first EVA in 2008, with recent missions contributing significantly to Tiangong construction.

Diversity achievements

Extravehicular activity (EVA) has historically been dominated by male participants, but significant strides in diversity have been made, particularly in gender, ethnicity, and nationality representation. The first woman to perform an EVA was Soviet cosmonaut , who conducted a 3-hour, 35-minute spacewalk on July 25, 1984, outside the Salyut 7 space station during the Soyuz T-12 mission. This milestone was followed three months later by astronaut , who became the first American woman to complete an EVA on October 11, 1984, during the mission aboard the , where she tested satellite refueling equipment for 3 hours and 29 minutes. In terms of ethnic diversity, astronaut made history as the first African American to perform an EVA on February 9, 1995, during the mission on the . His 4-hour, 38-minute spacewalk involved testing tools for future assembly. Harris's achievement highlighted the gradual inclusion of underrepresented ethnic groups in high-risk space operations. National firsts have expanded EVA participation globally. Chinese taikonaut Zhai Zhigang became the first person from his country to conduct a spacewalk on September 27, 2008, during the Shenzhou 7 mission, spending about 20 minutes outside the orbital module to test equipment and demonstrate extravehicular capabilities. More recently, astronaut achieved a regional milestone as the first Arab to perform an EVA on April 28, 2023, alongside astronaut Steve Bowen during on the ; the 7-hour, 1-minute spacewalk focused on upgrading station power systems. Recent developments underscore accelerating diversity in commercial and gender contexts. In September 2024, SpaceX engineer Sarah Gillis participated in the first commercial EVA during the Polaris Dawn mission, a private spaceflight led by Jared Isaacman, where she and Isaacman conducted a 1-hour, 46-minute "stand-up" spacewalk from the Dragon capsule to test new suits and procedures. On the gender front, the first all-female EVA occurred on October 18, 2019, when NASA astronauts Christina Koch and Jessica Meir replaced batteries on the ISS for 7 hours and 17 minutes, marking a breakthrough after decades of mixed or male-only walks. By May 2025, NASA had completed its fifth all-female spacewalk, with astronauts Anne McClain and Nichole Ayers preparing the ISS for new solar arrays during a nearly 6-hour EVA. Overall, EVA participation has progressed from exclusively male crews in the 1960s Gemini and Apollo programs to greater inclusivity, with women now accounting for an increasing share of spacewalkers—rising from zero to over 10% by the mid-2020s—and enabling all-female teams that demonstrate the feasibility of diverse crews in extravehicular operations.

Future directions

Advanced suits and technologies

Advancements in extravehicular activity (EVA) suits are focusing on enhanced mobility, durability, and integration of cutting-edge technologies to support extended operations in lunar and Martian environments beyond 2025. NASA's Exploration Extravehicular Mobility Unit (xEMU), developed in partnership with Axiom Space, is slated for debut during the Artemis III mission targeted for mid-2027, with potential delays to 2028, featuring dust-resistant materials to mitigate the abrasive effects of lunar regolith on suit integrity. The AxEMU design incorporates a regenerable carbon dioxide scrubbing system and advanced cooling to enable up to eight hours of lunar surface activity, with provisions for kneeling and improved flexibility over Apollo-era suits. Axiom Space is also advancing suits for low-Earth orbit operations, including a next-generation EVA system under NASA's xEVAS contract to replace aging suits, with initial capabilities targeted for integration around 2028. This system emphasizes commercial scalability and for prolonged station maintenance tasks. Technological integrations in these suits include AI-assisted task guidance to streamline astronaut procedures during EVAs. NASA's developments in AI for spacesuit design and procedure management enable real-time support, such as object detection and step-by-step instructions via interfaces, reducing in complex environments. Haptic feedback gloves enhance dexterity by providing tactile sensations through pressurized layers, allowing astronauts to better manipulate tools and sense surface textures without compromising suit integrity. Additionally, 3D-printed components facilitate custom-fit elements like joints and connectors, enabling and on-demand repairs for deep-space missions. Enhanced systems are pivotal for longer-duration EVAs, with closed-loop CO2 scrubbing technologies recycling exhaled into usable oxygen, minimizing resupply needs. These systems, evolved from prototypes, aim to support EVAs exceeding 16 hours by integrating efficient sorbents and humidity control. Robotic assistants complement human EVAs, with NASA's designed for Mars preparation tasks such as habitat setup and equipment handling in hazardous areas. Standing 1.8 meters tall and fully electric, operates autonomously or via to perform EVA-like functions, reducing crew exposure to and dust. In the commercial sector, is developing EVA suits tailored for missions to the Moon and Mars, with vacuum and environmental testing planned from 2026 onward to validate performance in partial gravity. These suits build on prototypes, incorporating integrated life support and mobility features for multi-day surface operations.

Lunar and planetary EVAs

The plans to conduct the first lunar surface extravehicular activity (EVA) since the Apollo era during the Artemis III mission, targeted for mid-2027, with potential delays to 2028, at the Moon's region. This mission will involve two astronauts descending from to the surface for scientific exploration, including sample collection and technology demonstrations, marking humanity's return to the lunar surface. The crew is expected to spend approximately one week on the surface, enabling up to five EVAs outside the lander to support objectives like resource prospecting in permanently shadowed craters. These lunar EVAs will utilize the Exploration Extravehicular Mobility Unit (xEMU) spacesuit, designed for enhanced mobility and durability during extended surface operations. The xEMU supports missions with stays of about 6.5 to 8 days, incorporating features to mitigate environmental hazards while allowing astronauts to traverse rugged terrain near the . NASA's plans for Mars exploration in the include crewed EVAs to conduct scientific fieldwork, habitat construction, and resource utilization, with missions relying on autonomous operations due to significant communication challenges. One-way communication delays between and Mars can reach up to 22 minutes, necessitating self-reliant EVA protocols without real-time ground support. Pressurized rovers will serve as mobile habitats, providing rest, recharge, and protection during multi-day excursions, with pre-deployed rovers enabling initial mobility for early EVAs. Conceptual studies extend EVA capabilities to other celestial bodies, including potential operations in the and Venus halo orbits, where the xEVA system is designed for microgravity to partial-gravity environments. For Venus, has explored floating platforms in the upper atmosphere as habitats for prolonged missions, potentially allowing EVAs in a high-altitude, buoyant environment to study cloud chemistry and atmospheric dynamics. Key challenges for these planetary EVAs include lunar regolith's abrasive properties, which can damage suit seals, mechanisms, and visors through electrostatic cling and mechanical wear. On Mars, global dust storms can reduce visibility, erode equipment, and prolong particle suspension due to the planet's 38% gravity, complicating safe traversal. Low-gravity adaptations are critical, with developing simulation systems like the Active Response Gravity Offload to train for altered gait patterns and physiological effects, as partial gravity on the (16% ) and Mars may not fully mitigate or balance issues during EVAs. NASA's 2025 Extravehicular Activity Technology Roadmaps outline a progression from lunar demonstrations to Mars operations under the Moon-to-Mars strategy, prioritizing suits and tools for extended surface mobility. These roadmaps target EVAs lasting over 100 hours on planetary surfaces, incorporating dust-resistant materials, radiation shielding, and autonomous to enable risk-reduced across diverse environments.

International and commercial expansion

The expansion of extravehicular activity (EVA) beyond traditional government-led programs on the (ISS) involves increasing contributions from international space agencies, focusing on orbital operations in (LEO) and collaborative frameworks. The (ESA) is enhancing its Columbus laboratory module through upgrades that support ongoing ISS EVAs while preparing for post-ISS LEO activities, including potential integrations with commercial destinations to maintain European access to spacewalks for research and maintenance. Similarly, the Japan Aerospace Exploration Agency () continues to utilize its Kibo module for external platform operations that enable EVAs, with plans to sustain these capabilities through the ISS's operational life into the late 2020s, facilitating international crew activities in microgravity. , Russia's space agency, is developing post-ISS orbital infrastructure, including a new national space station targeted for deployment after 2028, which will incorporate EVA capabilities for assembly, repairs, and scientific experiments independent of the ISS partnership. Commercial entities are poised to drive significant growth in orbital EVAs, leveraging private spacecraft and stations for crewed spacewalks starting in the mid-. SpaceX's vehicle, with planned crewed missions from 2026 onward, will support EVAs during orbital assembly and maintenance tasks, utilizing next-generation suits designed for enhanced mobility in LEO. Origin's station, a mixed-use commercial platform in development for the late , anticipates routine EVAs for module expansions, deployments, and tourism-related activities, fostering a environment in orbit. Axiom Space's private station, scheduled for full operations in the 2030s after detaching from the ISS, includes dedicated modules to enable independent EVAs for commercial , private missions, and station upkeep. International collaborations are expanding EVA opportunities through multilateral agreements that promote shared standards and access. The , signed by 60 nations as of November 2025, establish principles for cooperative space activities, including orbital EVAs on future LEO destinations, to ensure interoperability among partners. has invited international partners to join operations on its , offering opportunities for joint EVAs and experiments, building on its successful series of over 24 spacewalks conducted since 2008 as of November 2025. Key challenges in this expansion include the need for of EVA suits and procedures to enable seamless multinational and commercial operations, as varying designs could complicate missions and increase risks. Regulatory frameworks for private space activities remain evolving, with the U.S. updating guidelines for occupant to address commercial EVAs, though international harmonization lags behind. Projections indicate that commercial entities will account for a substantial portion of orbital EVAs by 2040, driven by the growth of the space economy to approximately $1 trillion annually, enabling expanded and research without relying solely on government .

References

  1. https://www.nasa.gov/learning-resources/for-kids-and-students/what-is-a-spacewalk-grades-k-4/
  2. https://ntrs.nasa.gov/api/citations/20120011735/downloads/20120011735.pdf
  3. https://www.nasa.gov/image-article/americas-first-spacewalk/
  4. https://www.nasa.gov/suits-and-rovers/
  5. https://www.nasa.gov/johnson/exhibits/extravehicular-activities/
  6. https://www.nasa.gov/international-space-station/space-station-spacewalks/
  7. https://www.sciencedirect.com/topics/physics-and-astronomy/extravehicular-activity
  8. https://www.nasa.gov/learning-resources/for-kids-and-students/what-is-a-spacewalk-grades-5-8/
  9. https://www.nasa.gov/history/alsj/alsj-EVA-Tethers-SafetyLines.html
  10. https://www.nasa.gov/history/alsj/a15/a15.seva.html
  11. https://www.nasa.gov/reference/11-0-spacesuits-vol-2/
  12. https://www.nasa.gov/news-release/nasa-space-x-create-new-era-of-space-exploration-with-private-spacewalk/
  13. https://www.nasa.gov/directorates/esdmd/hhp/space-suits-and-exploration-operations/
  14. https://spinoff.nasa.gov/Spinoff2005/ch_1.html
  15. https://spinoff.nasa.gov/astronaut-remote-health-monitoring
  16. https://www.nasaspaceflight.com/2025/01/iss-roundup-012425/
  17. https://www.nasa.gov/centers-and-facilities/johnson/spacewalk-spacesuit-basics/
  18. https://www.americanscientist.org/article/the-past-and-future-space-suit
  19. http://www.astronautix.com/b/berkut.html
  20. https://airandspace.si.edu/stories/editorial/how-two-cold-war-spacewalks-came-common-technological-solution
  21. https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/1860282/gemini-g4c-space-suit1966/
  22. https://airandspace.si.edu/collection-objects/pressure-suit-a7-l-armstrong-apollo-11-flown/nasm_A19730040000
  23. https://www.asme.org/about-asme/engineering-history/landmarks/255-apollo-space-suit
  24. https://www.nasa.gov/wp-content/uploads/2015/07/2019_07_ea_emu.pdf
  25. https://www.russianspaceweb.com/orlan_mks.html
  26. http://www.china.org.cn/china/shenzhouVII_spacewalk/2008-09/25/content_16533059.htm
  27. https://www.space.com/spacex-new-eva-spacewalking-spacesuit-video
  28. https://www.nasa.gov/humans-in-space/spacesuit-for-nasas-artemis-iii-moon-surface-mission-debuts/
  29. https://www.axiomspace.com/news/axemu-spacesuit-testing
  30. https://mynews13.com/fl/orlando/space/2024/12/05/nasa-pushes-artemis-ii-and-iii-missions-to-new-dates
  31. https://ntrs.nasa.gov/citations/19960025621
  32. https://www.nasa.gov/history/alsj/WOTM/WOTM-SCB.html
  33. https://ntrs.nasa.gov/citations/19960020257
  34. https://www.nasa.gov/image-article/a-safer-way/
  35. https://ntrs.nasa.gov/citations/20060023368
  36. https://www.nasa.gov/reference/jsc-eva-systems/
  37. https://sma.nasa.gov/SignificantIncidentsEVA/
  38. https://www.nasa.gov/international-space-station/mobile-servicing-system/
  39. https://www.space.com/china-space-station-robotic-arm-construction-test
  40. https://www.nasa.gov/blogs/stationreport/2021/06/25/iss-daily-summary-report-6-25-2021/
  41. https://www.nasa.gov/wp-content/uploads/2023/03/conkin-prebreathe-overview-tp216147-2011.pdf
  42. https://www.nasa.gov/wp-content/uploads/2023/12/ochmo-tb-037-decompression-sickness.pdf
  43. https://www.nasa.gov/wp-content/uploads/2023/03/gernhardt-eva-ops-chp-5.4-2013.pdf
  44. https://www.nasa.gov/johnson/neutral-buoyancy-laboratory/
  45. https://www.nasa.gov/virtual-reality-lab-doug/
  46. https://ntrs.nasa.gov/api/citations/20200011545/downloads/20200011545.pdf
  47. https://core.ac.uk/download/pdf/42732407.pdf
  48. https://www.space.com/space-exploration/international-space-station/spacewalking-russian-cosmonauts-install-experiments-on-the-international-space-station
  49. https://www.nasa.gov/wp-content/uploads/2020/01/topic_1-_eva_lunar_surface_concept_of_operations.pdf
  50. https://ntrs.nasa.gov/api/citations/20140003773/downloads/20140003773.pdf
  51. https://www.nasa.gov/wp-content/uploads/2017/02/esoc-13_rev._v_emu_hardware_data_book_jsc-e-daa-tn55224.pdf
  52. https://www.nasa.gov/wp-content/uploads/2017/02/eva-exp-0042_xeva_system_con_ops_rev_b_final_dtd_10192020_ref_doc.pdf
  53. https://nlsp.nasa.gov/explore/api/v1/getfiles3?id=IDP-LSDA_DOCUMENT-0000000000002705&type=lsda_document&alias=lsda
  54. https://spaceref.com/space-stations/nasa-space-station-on-orbit-status-9-april-2019-post-spacewalk-medical-checkups-today/
  55. https://www.lpi.usra.edu/lunar/artemis/resources/AbercrombyEtAl_CrewHealth-EVA-Roadmap2020_NASA-TP-20205007604.pdf
  56. https://www.nasa.gov/wp-content/uploads/2017/02/neemo_22_eva_overview_and_debrief_eva-exp-0054.pdf?emrc=d7cb1a
  57. https://ntrs.nasa.gov/api/citations/20230002544/downloads/EVA23_Lessons_Learned_BASE%282a%29.pdf
  58. https://ntrs.nasa.gov/api/citations/20220004017/downloads/2021%2520EVA%2520Injury%2520Evidence%2520Report%2520Final.docx.pdf
  59. https://pubmed.ncbi.nlm.nih.gov/8280036/
  60. https://ntrs.nasa.gov/api/citations/20040065979/downloads/20040065979.pdf
  61. https://pmc.ncbi.nlm.nih.gov/articles/PMC3997516/
  62. https://www.nasa.gov/wp-content/uploads/2023/03/radiation-protection-technical-brief-ochmo.pdf
  63. https://ntrs.nasa.gov/citations/19920013110
  64. https://ntrs.nasa.gov/api/citations/19690004637/downloads/19690004637.pdf
  65. https://www.nasa.gov/reference/risk-of-spaceflight-associated-neuro-ocular-syndrome-sans/
  66. https://pmc.ncbi.nlm.nih.gov/articles/PMC10397180/
  67. https://ntrs.nasa.gov/api/citations/20170003942/downloads/20170003942.pdf
  68. https://ntrs.nasa.gov/api/citations/19880003545/downloads/19880003545.pdf
  69. https://sma.nasa.gov/SignificantIncidents/assets/2024/Significant_Incidents_in_EVA_2024.pdf
  70. https://www.nasa.gov/wp-content/uploads/2023/07/suit_water_intrusion_mishap_investigation_report.pdf
  71. https://www.hou.usra.edu/meetings/orbitaldebris2019/orbital2019paper/pdf/6001.pdf
  72. https://appel.nasa.gov/2014/02/27/mishap-investigation-board-briefing-on-spacesuit-water-intrusion/
  73. https://spacepolicyonline.com/news/nasa-scrubs-spacewalk/
  74. https://ntrs.nasa.gov/api/citations/19980017419/downloads/19980017419.pdf
  75. https://www.swpc.noaa.gov/noaa-scales-explanation
  76. https://oig.nasa.gov/wp-content/uploads/2025/09/final-report-ig-25-012-nasas-management-of-iss-extravehicular-activity-spacesuits.pdf
  77. https://www.nasa.gov/mission/sts-41-b/
  78. https://www.nasa.gov/history/photos-from-sts-41b/
  79. https://www.spacefacts.de/eva/e_eva.htm
  80. https://www.nasa.gov/mission/expedition-2/
  81. https://www.space.com/spacex-polaris-dawn-first-private-spacewalk
  82. https://www.nasaspaceflight.com/2024/09/polaris-dawn-spacewalk/
  83. https://www.nasaspaceflight.com/2008/03/sts-123-completes-eva-2-dextre-gains-its-arms/
  84. https://www.spacefacts.de/tiangong/english/crew_1.htm
  85. https://aerospaceamerica.aiaa.org/features/tomorrows-spacesuits/
  86. https://www.guinnessworldrecords.com/world-records/493960-most-accumulated-time-on-spacewalks-by-a-male
  87. https://www.guinnessworldrecords.com/records/hall-of-fame/peggy-whitson-most-spacewalks-by-a-female
  88. https://www.nasa.gov/missions/apollo/apollo-17-mission-details/
  89. https://www.nasa.gov/mission/expedition-13/
  90. https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Astrolab/Expedition_13
  91. https://www.space.com/svetlana-savitskaya-biography
  92. https://www.nasa.gov/history/kathryn-sullivan-the-first-american-woman-to-walk-in-space/
  93. https://www.history.com/this-day-in-history/february-9/bernard-harris-becomes-the-first-black-man-to-walk-in-space
  94. https://www.space.com/5902-chinese-astronauts-complete-spacewalk.html
  95. https://www.space.com/sultan-al-neyadi-first-spacewalk-arab-astronaut
  96. https://www.cnn.com/2024/09/12/science/spacewalk-polaris-dawn-mission-spacex
  97. https://www.nasa.gov/blogs/spacestation/2019/10/18/nasa-astronauts-wrap-up-historic-all-woman-spacewalk/
  98. https://abcnews.go.com/US/nasa-astronauts-prepare-5th-female-spacewalk/story?id=121270736
  99. https://www.collectspace.com/news/news-101624a-axemu-lunar-spacesuit-axiom-space-prada-reveal.html
  100. https://www.yahoo.com/news/articles/spacex-starship-timeline-delays-astronaut-193624867.html
  101. https://www.axiomspace.com/news/eva-leo-contract
  102. https://www.nasaspaceflight.com/2025/10/iss-artemis-eva-suits/
  103. https://www.nasa.gov/wp-content/uploads/2024/09/19-life-support-co2-removal-spec-sheet-508.pdf?emrc=546f3a
  104. https://www.media.mit.edu/publications/feeling-through-spacesuits-application-of-space-resilient-e-textiles-to-enable-haptic-feedback-on-pressurized-extravehicular-suits-1/
  105. https://www.sae.org/papers/tactile-sensing-gloves-extravehicular-activity-2009-01-2498
  106. https://www.spacedaily.com/reports/ND_Professor_patents_3D_printing_of_spacesuits_999.html
  107. https://commons.und.edu/cgi/viewcontent.cgi?article=1005&context=ss-fac
  108. https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Research/Advanced_Closed_Loop_System
  109. https://ttu-ir.tdl.org/server/api/core/bitstreams/61809a81-6afe-4d97-a16b-03b0ec16283c/content
  110. https://techport.nasa.gov/projects/9707
  111. https://www.nasa.gov/podcasts/houston-we-have-a-podcast/valkyrie/
  112. https://www.nasa.gov/wp-content/uploads/2023/06/r5-fact-sheet.pdf
  113. https://www.spacex.com/updates
  114. https://www.nasaspaceflight.com/2025/11/starship-block-3-path-moon/
  115. https://www.nasa.gov/mission/artemis-iii/
  116. https://www.nasa.gov/missions/artemis/artemis-iii/
  117. https://www.nasa.gov/humans-in-space/spacesuits-built-to-handle-pressure/
  118. https://ntrs.nasa.gov/api/citations/20220013418/downloads/ASCEND-Communication%2520Delays%252C%2520Disruptions%252C%2520and%2520Blackouts%2520for%2520Crewed%2520Mars%2520Missions.pdf
  119. https://science.nasa.gov/resource/aerial-platforms-for-the-scientific-exploration-of-venus/
  120. https://ntrs.nasa.gov/api/citations/20220008062/downloads/The%2520Challenge%2520of%2520Lunar%2520Dust%2520-%2520v4.pdf
  121. https://www.nasa.gov/solar-system/the-fact-and-fiction-of-martian-dust-storms/
  122. https://ntrs.nasa.gov/api/citations/20250004024/downloads/ICES-2025-61.pdf
  123. https://ntrs.nasa.gov/citations/20250004024
  124. https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Preparing_for_European_commercial_presence_in_low_Earth_orbit
  125. https://humans-in-space.jaxa.jp/en/kibo/
  126. https://www.livescience.com/russia-withdraw-iss-2025
  127. https://www.youtube.com/watch?v=KtVZAnLbu0E
  128. https://www.sierraspace.com/commercial-space-stations/orbital-reef-space-station/
  129. https://www.axiomspace.com/axiom-station
  130. https://www.nasa.gov/artemis-accords/
  131. https://payloadspace.com/the-artemis-accords-by-the-numbers/
  132. https://www.unoosa.org/pdf/pres/copuos2014/tech-24.pdf
  133. https://www.facebook.com/XinhuaSciTech/posts/china-has-successfully-carried-out-20-astronaut-extravehicular-activities-evas-o/1145647300931003/
  134. https://news.cgtn.com/news/2025-08-18/Chinese-spacesuit-reaches-20-spacewalks-extending-in-orbit-lifespan-1FWyUx3xGuc/p.html
  135. https://oig.nasa.gov/docs/IG-17-018.pdf
  136. https://www.congress.gov/crs-product/R48050
  137. https://www.cnbc.com/2022/05/21/space-industry-is-on-its-way-to-1-trillion-in-revenue-by-2040-citi.html
Add your contribution
Related Hubs
User Avatar
No comments yet.