Restart shuttle: Fwd: First 50 Years of Spacewalking

Sent from my iPad

Begin forwarded message:

From: "Gary Johnson" <gjohnson144@comcast.net>
Date: March 23, 2015 at 11:22:03 AM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: First 50 Years of Spacewalking

AmericaSpace
For a nation that explores
March 18th, 2015
'Working a Monkey Board': The First 50 Years of Spacewalking (Part 1)
By Ben Evans

Five decades have now passed since humanity's first foray beyond the confines of their pressurized spacecraft and into the airless void beyond. Photo Credit: NASA
Fifty years ago, today, on 18 March 1965, a 30-year-old Soviet cosmonaut named Alexei Leonov became the first human in history to depart the confines of his spacecraft in a pressurized suit and float freely into the limitless void beyond. As described in two previous AmericaSpace history articles—available here and here—Leonov spent 12 minutes outside the Voskhod 2 spacecraft, tumbling in the void, as part of the latest in a line of Soviet spectaculars, designed to outdo the United States. It had long been apparent that spacewalking, or "Extravehicular Activity" (EVA), was a central tenet of Project Gemini that NASA needed to master, before sending humans to the Moon in fulfilment of President John F. Kennedy's bold challenge. The first U.S. spacewalk, by astronaut Ed White, occurred a few weeks later, in June 1965, and ushered in a new technology which would see humans explore the surface of the Moon, weld, repair, and upgrade satellites and space telescopes, work in untethered conditions, and build one of the brightest objects in Earth's skies: the International Space Station (ISS).
Leonov's iconic spacewalk, ironically, today places him at the very bottom of the list of 211 men and women from Russia, the United States, France, Germany, Japan, Switzerland, Canada, Sweden, China, and Italy who have embarked on EVAs in low-Earth orbit, in cislunar space, and upon the Moon's surface over the past half-century, most recently by Terry Virts. Floating through an extendable airlock, Leonov emerged from Voskhod 2's outer hatch on his "back," which revealed the grandeur of Earth to one of humanity's sons for the first time. "I felt the power of the human intellect that had placed me there," Leonov wrote in his memoir, Two Sides of the Moon, co-authored with U.S. astronaut Dave Scott. "I felt like a representative of the human race … I was overwhelmed by these feelings." A bracketed movie camera returned fuzzy images of the top of Leonov's helmet, together with his shoulders and arms, and later his entire body, but the triumph of the EVA almost ended badly, when his suit "ballooned" and proved incredibly difficult to force himself back into the airlock.
Although successful, Leonov's spacewalk was a direct response to the U.S. plan to demonstrate EVA from its own Gemini spacecraft. In July 1964, Jim McDivitt and Ed White had been assigned to Gemini IV, originally for a seven-day mission to evaluate the performance of fuel cells for the first time. Several missions were in the running to undertake America's first spacewalk—as were several candidates, namely Gemini IV's White, Gemini V's Charles "Pete" Conrad, and Gemini VI's Tom Stafford—but the Soviet triumph pushed much of the planning not to the right, but to the left.
Assisted into the Gemini IV spacecraft by McDonnell technicians, this view shows the smallness of the place that Jim McDivitt and Ed White called "home" for four days in June 1965. Photo Credit: NASA
NASA documentation from January 1964 had flagged Gemini IV as the earliest possible flight on which a brief "stand-up" EVA might be attempted, although the availability of equipment presented a major stumbling block and made it more likely that an actual "egress" might not occur until Gemini V or VI. Indeed, in his autobiography, We Have Capture, Stafford wrote that by the time he and fellow astronaut Wally Schirra were formally named to Gemini VI in April 1965, they had known for a year that "we would be flying a very exciting mission" and "I would be taking the first American spacewalk," but it soon became clear than an EVA would not form part of it. Realigned to occur on Gemini V in August 1965, Alexei Leonov's EVA prompted NASA management to discuss moving America's first spacewalk further forward to Gemini IV in June. "It was pretty clear to us that we were in a race," wrote Deke Slayton in his memoir, Deke. "The Soviet press even said that Leonov's EVA suit was a prototype for a lunar surface pressure suit."
In fact, links had been drawn between spacewalking and Gemini IV virtually as soon as McDivitt and White were assigned to the mission and, at the July 1964 press conference, Deputy Program Manager Kenny Kleinknecht announced that one of them might indeed perform a stand-up EVA. The "long pole" remained the availability of equipment, but as the year progressed the AiResearch Manufacturing Company was contracted to build a small chest pack, the David Clark Company received specifications to fabricate the bulky white suit, and McDonnell set to work modifying the Gemini IV spacecraft to support an extravehicular option. The astronauts themselves lobbied strongly for the addition of the G4C extravehicular suit to their mission—equipped with redundant zippers, a pair of outer visors, automatic-locking ventilation settings, and a heavy outer covering—and, in their 1977 history of Project Gemini, Barton Hacker and James Grimwood wrote that McDivitt and White "went far beyond that of the normal test pilot in determining what was to be done and when."
Altitude chamber tests in November 1964 proved successful, and in the immediate aftermath of Voskhod 2 Bob Gilruth, head of the Manned Spacecraft Center (MSC) in Houston, Texas, and his deputy, George Low, reviewed a hand-held maneuvering unit and lent their support. By mid-May, they had gained the approval of NASA Associate Administrator Bob Seamans, who in turn described the EVA plan for Gemini IV to Administrator Jim Webb and Deputy Administrator Hugh Dryden. One note of concern came from George Mueller, then-head of Manned Space Flight, who doubted that the EVA hardware would be ready for Gemini IV's targeted launch date. His fears were soon allayed, but Dryden was concerned that the EVA would be perceived as little more than a knee-jerk response to Leonov's success. At length, he relented and gave offered his approval, scribbled in the corner of Seamans' report, on 25 May 1965.
Maneuvering by means of a hand-held propulsion device, Ed White spacewalked across the central Pacific Ocean and the continental United States. Photo Credit: NASA
By this stage, Gemini IV's official press kit had made reference to a "possible extravehicular activity," which became a certainty just a few days later. Nor would Ed White merely stand on his seat and poke his head through the upper hatch; he would actually leave the spacecraft and maneuver around with the aid of his hand-held device. Following their launch on 3 June, White ventured outside the spacecraft for 21 minutes and "walked" across part of the world, starting over the central Pacific, over California and later Texas, and eventually reaching southern Florida and the island chains of Cuba and Puerto Rico. From inside Gemini IV, McDivitt was concerned that his photography of the event was "not very good," but in reality his images of America's first spacewalker proved an iconic record of the early annals of space exploration.
The first few piloted Gemini missions had been assigned very specific tasks—an inaugural shakedown of the vehicle on Gemini 3, the EVA on Gemini IV, long-duration and fuel cells on Gemini V, rendezvous on Gemini VI, and long-duration on Gemini VII—but each of the final six flights of the program were expected to feature a spacewalk of significantly greater complexity than had been performed by White.
First up was Dave Scott on Gemini VIII, who was tasked with spending two hours and 40 minutes outside his spacecraft in March 1966. He would wear an Extravehicular Life Support System (ELSS) on the chest of his suit to feed oxygen from the spacecraft supply and from a backpack, known as the Extravehicular Support Package (ESP), on the rear adapter of Gemini VIII. He would have maneuvered himself to the back of the spacecraft and secured himself into the backpack, a procedure which had required hundreds of hours of training in parabolic aircraft, underwater and on air-bearing tables, before launch. Working outside for 10 times longer than White did, Scott would have to retrieve an experiments package, activate a micrometeoroid detector on Gemini VIII's Agena-D target vehicle, and test a reactionless power wrench. Unfortunately, a near-catastrophic sequence of problems experienced by Gemini VIII caused its three-day mission to be curtailed after just 10 hours, and Scott never had the opportunity to perform his long-awaited EVA.
By the time Gemini VIII flew, many of the plans for the EVA on Gemini IX had also been thrown into disarray, following the tragic death of its crew, Elliot See and Charlie Bassett, in an aircraft crash. Under the original plans, Bassett would have test-flown the U.S. Air Force's Astronaut Maneuvering Unit (AMU)—a device which his backup, astronaut Gene Cernan, described in his autobiography, The Last Man on the Moon, as "like a massive suitcase," which was "so big that it would be carried aloft folded up like a lawn chair and attached within the rear of the Gemini"—through at least one 90-minute orbit of Earth, controlling his motions with hydrogen peroxide thrusters. Throughout the late fall of 1965 and into the spring of 1966, Bassett and Cernan physically conditioned themselves in the gym and at the handball court to prepare for the strength and stamina needed to operate inside their suits.
Gene Cernan's EVA was the longest to date, by far the most complex … and intrinsically hazardous. Photo Credit: NASA
Those suits were extensively modified from the version worn by Ed White, in order to offer additional comfort and protection and to accommodate the demands of EVA. They included a white cotton long-john-type undergarment for the men's biosensors, a nylon "comfort layer," a Dacron-Teflon link net to maintain the suit's shape, and several layers of aluminized Mylar and nylon for thermal and micrometeoroid protection. The death of See and Bassett in February 1966 meant the Gene Cernan and Tom Stafford were promoted from their status on the Gemini IX backup crew to the new prime crew, and they ended up flying the mission in June.
As described in a previous AmericaSpace article, Cernan's EVA originally encompassed the retrieval of a micrometeoroid package from an Agena-D target vehicle, although this was scratched when the latter experienced a launch failure and ended up at the bottom of the Atlantic Ocean. Years later, Cernan described donning his suit umbilicals inside the cramped Gemini to unleashing a garden hose in a volume no larger than the front seat of a car. Venturing outside, his initial thought was that he was "sitting on God's front porch," as orbital darkness gave way to the first rays of a shimmering dawn, and he quickly set to work positioning a camera and retrieving an experiment. However, he very soon came face to face with the harsh reality of spacewalking. Every move affected his entire body, rippling through his umbilical and jostling the spacecraft, in a phenomenon that Cernan likened to wrestling an octopus. One of his recommendations after the flight was for more handrails and an improved propulsion system for controllability.
At length, he moved to the rear of Gemini IX to strap himself into the AMU. However, the stiffness of his suit fought his every move, and as he struggled through his tasks his heart rate peaked at 195 beats per minute and his struggling environmental control system had fogged up his visor. Unable to wipe the stinging sweat from his eyes, Cernan had no choice but to rub his nose on the inside of his visor, just to make a "hole" through which he could see. Working without leverage on the AMU, he found it difficult to turn knobs or extend its armrests, and by this stage Stafford and Mission Control were becoming seriously concerned about his well-being. He was expending energy at a rate equivalent to running up a hundred stairs every minute, and it was Stafford who called an end to the EVA. By the time the beetroot-faced Cernan returned inside Gemini IX, no fewer than 128 minutes had elapsed. He was doused with weightless water droplets from a water pistol, and strips of skin on his swollen hands tore away as he removed his gloves. "When he raised his helmet visor," wrote Stafford in his autobiography, "I saw that his face was hot pink, like he'd been baked in a sauna too long."
Pictured in the cabin ahead of his spacewalk, Dick Gordon became the fourth American to perform an EVA on Gemini XI. Photo Credit: NASA
Cernan's experience demonstrated that EVA was inherently dangerous. Seven weeks later, in July 1966, Gemini X's Mike Collins became the first human being to record two periods of spacewalking. His first excursion lasted just under an hour and saw him stand on his seat to set up an ultraviolet camera, whilst the second EVA allowed him to actually move outside the spacecraft to retrieve an experiment package from the Agena-D target vehicle. In spite of the greater success of Gemini X, the need to practice spacewalking in a realistic environment had led to the formal adoption of "neutral buoyancy"—submerging fully-suited astronauts in a water tank—as the closest terrestrial analog to the real thing.
In his memoir, Carrying the Fire, Collins related that neutral buoyancy training was introduced shortly before Gemini X, but he had little spare time to practice under such conditions. Gene Cernan, on the other hand, undertook the training and found that it did indeed approximate his efforts in space. Hardware changes were also implemented. "NASA engineers reconfigured future spacecraft and installed a lot of new handholds, railings and stirrups into which future spacewalkers could lock their boots," related Cernan in The Last Man on the Moon. "These worked so well that we called them the Golden Slippers."
Yet the difficulties remained. In September 1966, Gemini XI's Dick Gordon found himself constantly fighting against his suit to keep himself from floating away, which impaired his ability to complete all of his tasks and left him soaked with sweat and with stinging eyes. Thirty-three minutes into the planned 107-minute EVA, he returned inside the cabin, after crewmate Pete Conrad told Mission Control that Gordon had gotten so hot and sweaty that his visibility was drastically reduced. "Those guys were two of the best we had in the program and their problems served to validate mine," Cernan reflected, "which meant I was no longer the only astronaut who had trouble working in space."
On Gemini XII, Buzz Aldrin became the first human being to embark on three discrete sessions of extravehicular activity. Photo Credit: NASA
Not until Gemini XII in November 1966 were the fundamentals of basic EVA tasks successfully demonstrated without incident. In light of the difficulties, a final test of the AMU was deleted, in favor of astronaut Buzz Aldrin removing, installing, and tightening bolts with a power tool, operating connectors and hooks, stripping Velcro, and cutting cables. Aldrin spent a considerable amount of time performing neutral buoyancy training, clad in a carefully-ballasted suit to closely approximate the effects of the microgravity environment. Although disparagingly described by Cernan as "working a monkey-board"—a remark with which Aldrin broadly agreed in his memoir, Men from Earth—the work on Gemini XII served to remove another basic doubt in the collective mind of NASA before EVAs could be attempted on the Moon.
Aldrin also became the first person to embark on as many as three discrete sessions of EVA. His first spacewalk saw him install and retrieve experiment packages and his suit did not overheat, thanks to a regimen of two-minute rest breaks, whilst his second saw him connect a tether between Gemini XII and the Agena-D target vehicle for a gravity gradient exercise. "Back in the buoyancy pool, I had torqued bolts and cut metal dozens of times—what I used to call 'chimpanzee work'—and I had no problem with these chores in space," he recalled in Men from Earth. "Someone even put a bright yellow paper Chiquita Banana sticker at my busy box." A final stand-up EVA saw Aldrin dispose of unwanted equipment, wrapping up his third session of extravehicular activity after a total of 5.5 hours.
With Gemini XII, the program ended and the door was ajar for the dawn of Project Apollo, and its goal of planting U.S. boots on the Moon before the end of the decade. That momentous accomplishment would carry the suits and tools and techniques of spacewalking—both figuratively and literally—to their greatest heights and would see astronauts working on an alien surface, and in the equally alien domain of cislunar space, for many hours at a time.

Copyright © 2015 AmericaSpace - All Rights Reserved

AmericaSpace
For a nation that explores
March 19th, 2015
Walking on an Alien World: The First 50 Years of Spacewalking (Part 2)
By Ben Evans

A mere four years after humanity's first spacewalk, EVA and space suit technology advanced sufficiently to permit Neil Armstrong's historic first steps on the Moon. Photo Credit: NASA
Fifty years ago, yesterday, on 18 March 1965, humanity became an "extravehicular" spacefaring civilization for the first time, when 30-year-old Soviet cosmonaut Alexei Leonov ventured outside his Voskhod 2 spacecraft and spent 12 minutes floating in the void. By the fall of 1966, no fewer than five U.S. astronauts had done likewise, with Gemini XII's Buzz Aldrin spending a cumulative 5.5 hours outside his ship in three discrete sessions of Extravehicular Activity (EVA). As described in yesterday's AmericaSpace article, spacewalking was considered a crucial step toward the U.S. goal of accomplishing bootprints on the Moon before the end of the decade. However, the astronauts had come face to face with the hazardous realities and difficulties of EVA, and the first efforts had begun to develop better training analogs on the ground.
By the dawn of 1967, five U.S. spacewalkers—Ed White, Gene Cernan, Mike Collins, Dick Gordon, and Buzz Aldrin—had ventured outside their respective spacecraft. With the loss of the Apollo 1 crew in a catastrophic fire on the launch pad and the tragic death of Soviet cosmonaut Vladimir Komarov during the failed re-entry of Soyuz 1, both the U.S. and Soviet human space programs ground to a halt for almost two years, and it was not until January 1969 that spacewalkers again emerged from their craft. On that occasion, Soviet cosmonauts Alexei Yeliseyev and Yevgeni Khrunov performed the first multi-person spacewalk, maneuvering from the docked Soyuz 5 to Soyuz 4 spacecraft and becoming the first crew members to return to Earth in a different craft to the one in which they launched. Their experience demonstrated that "spacewalking" was something of a misnomer and that the most efficient form of locomotion was a hand-over-hand progression, using rails and handholds on the exterior of the spacecraft.
In March 1969, U.S. astronauts Jim McDivitt, Dave Scott, and Rusty Schweickart were launched on a full dress rehearsal of the complete Apollo spacecraft—command, service, and lunar modules—in low-Earth orbit. During the course of the Apollo 9 mission, it was intended that McDivitt and Schweickart would undock the lunar module from Scott in the command module and perform formation-flying. Additionally, Schweickart would perform an EVA outside the lunar module, wearing a similar suit to that planned for the first landing on the Moon. However, there existed another EVA element to Apollo 9. If a problem arose preventing the lunar module from redocking with the command and service module, McDivitt and Schweickart would have been required to perform a spacewalking transfer. This was hampered by the fact that McDivitt, who was not scheduled to perform an EVA, would have been wholly reliant upon the emergency oxygen supply in Schweickart's suit. "If he didn't make the EVA transfer within 45 minutes," wrote Dave Scott in his memoir, Two Sides of the Moon, "he would die."
Rusty Schweickart's EVA sought to determine the effectiveness of the lunar surface suit in a vacuum. Unlike previous suits, it was completely self-contained. Photo Credit: NASA
Schweickart's EVA was compounded by a severe bout of space sickness, which seriously forced mission managers to consider curtailing or even canceling it. The plan called for the spacewalk to occur whilst the two spacecraft were still docked and would have seen him spend 135 minutes outside, exiting the lunar module's square hatch and making his way, via handrails, over to the open hatch of the command module, where a fully-suited Scott would perform a stand-up EVA to photograph his progress. As well as evaluating how well the suit held up to "real" radiation and vacuum conditions, it would also serve as a test of how well a returning lunar surface crew could spacewalk over to the command module in the event that they were unable to pass through the docking tunnel.
In light of Schweickart's sickness, the tasks were hurriedly reprioritized and culminated in a relatively straightforward, 45-minute opening of the hatch, exposing him and McDivitt and their suits to vacuum, but keeping them both inside the lunar module. Fortunately, Schweickart recovered and the EVA went ahead. Anchored by a tether, he squeezed through the hatch and onto the lunar module's porch, clad in the "A7L" suit, built by ILC Dover of Delaware. It incorporated integrated thermal and micrometeoroid layers and consisted of a single-piece "torso-limb" structure, with convoluted joints of synthetic rubber at its shoulders, elbows, wrists, hips, ankles, and knees, and a system of "link-net" mesh to keep it from ballooning under pressure. Metallic rings at the neck and forearms provided for the attachment of helmet and gloves.
"What was important about this EVA," explained Deke Slayton in his autobiography, Deke, "was that the lunar pressure suit was completely self-contained. All the suits used on the Gemini EVAs had relied on the spacecraft to provide oxygen and communications." With the Apollo suit, all of this resided in the massive Portable Life Support System (PLSS) backpack. Moving outside, Schweickart fastened himself into a pair of "golden slippers" on the porch, as Dave Scott—connected to the command module's life-support utilities—poked his own helmeted head into space for a stand-up EVA. Schweickart captured impressive film footage of Scott, as well as imagery of both spacecraft, before returning back inside the lunar module. The suit which would sustain the first Moonwalkers had passed its initial testing in the space environment with flying colors.
Very few images exist of Neil Armstrong on the lunar surface, mainly because he conducted the majority of the photography. However, this view of him working in the shadow of the lunar module Eagle is arguably the best full-body shot of the First Man on humanity's first EVA on another world. Photo Credit: NASA
With the conclusion of Apollo 9, the next time an American citizen would venture outside his spacecraft would be the initial steps of Neil Armstrong and Buzz Aldrin on the surface of the Moon in July 1969. Original plans called for the astronauts to sleep after achieving humanity's first landfall on an alien world, but that proved about as likely as telling a child to sleep on Christmas morning, and Armstrong elected shortly after touchdown to press ahead with "EVA Prep." Donning their lunar surface equipment—rubber-soled boots, backpacks, oxygen hoses, coolant umbilicals, outer helmets, and chest-mounted control packs—took time and was exacerbated by the cramped nature of the lunar module's cabin, which Aldrin later described as akin to a pair of fullbacks in a Cub Scout tent.
At length, the square hatch was opened and Armstrong dropped to his knees, his head facing the rear of the cabin, and planted his feet into the opening which marked the threshold to the Moon. The images which followed retain their ethereal quality, even decades later, as he maneuvered onto the porch and descended the nine-rung ladder to the surface. At 10:56:15 p.m. EDT on 20 July 1969, with the immortal words "That's one small step for man, one giant leap for mankind," he became the first representative of humanity to set foot on another world, a mere four years since EVA had first been pioneered. Aldrin joined him in short order and the two men set up experiments and the U.S. flag, gathered soil and rock samples, and spoke directly to President Richard Nixon, who congratulated them on their achievement.
Performing EVA on another celestial body, they found that the most natural gait was a loping motion, in which they alternated feet, pushed off with each step, and floated ahead, then planted the other foot. Other techniques included "skipping strides" and "kangaroo hops," necessitated by the peculiar one-sixth terrestrial gravity. They had to take care when turning and stopping. "I noticed immediately that my inertia seemed much greater," Aldrin wrote in his memoir, Men from Earth. "Earthbound, I would have stopped my run in just one step … an abrupt halt. I immediately sensed that if I tried this on the Moon, I'd be face-down in the lunar dust. I had to use two or three steps to sort of wind down. The same applied to turning around. On Earth, it's simple, but on the Moon, it's done in stages." In total, Armstrong spent two hours and 14 minutes on the surface; Aldrin a little less, at one hour and 46 minutes.
Dave Scott works with the rover on the slopes of Hadley Rille during Apollo 15. Photo Credit: NASA
Over the course of the next 3.5 years, a further 10 U.S. citizens would walk the surface of the Moon, spending increasingly longer durations outside the lunar module and embarking on increasingly more complex tasks. On Apollo 12 in November 1969, astronauts Charles "Pete" Conrad and Al Bean performed two EVA sessions on the surface, retrieving equipment from the Surveyor 3 lander, establishing experiments, digging trenches, and collecting, documenting, and photographing rock and soil samples. The one-sixth terrestrial gravity carried its own peculiarities. "A simple thing like shoveling soil into a sample bag was an entirely new experience," explained Conrad. "First, you had to handle the shovel differently, stopping it before you would have on Earth, and tilting it to dump the load much more steeply, after which the whole sample would slide off suddenly." Hopes to acquire color TV footage had been ruined by inadvertently pointing the camera directly at the Sun, and efforts to take a photograph of Conrad and Bean together had failed when the timer disappeared. It was discovered toward the end of the second EVA, too late for them to take what would have been a remarkable—and historically unique —image.
With two Moonwalks having been scheduled for Apollo 13, the objectives of this "Successful Failure" to land at the Fra Mauro highland site was moved to the next flight, Apollo 14, in January 1971. Astronauts Al Shepard and Ed Mitchell performed two EVAs, utilizing a two-wheeled Modular Equipment Transporter (MET) to carry their tools. Unfortunately, it tended to become bogged down in lunar dust, which proved thicker than the soils encountered by the Apollo 11 and 12 crews, and was likened to dragging a golf buggy through deep sand. The situation was worsened by the fact that it was also lightweight and tended to bounce in the low lunar gravity, meaning that one man had to follow behind, picking up items which fell off.
Shepard and Mitchell noticed that walking on an alien world proved difficult in other ways, too, since the harsh glare of sunlight made shadows unreliable and rendered distance impossibly hard to judge. With no visible points of reference, craters seemed to appear at their feet, as if from nowhere, and boulders which seemed to be some way off were suddenly upon them. This proved particularly troublesome when, during their second EVA, they attempted to find the rim of the large Cone Crater—one of their major geological objectives—but "checkpoint" craters on their map were hard to identify and the whole region seemed to be an endless sea of sand dunes. Sometimes, Shepard wrote in third-person narrative in Moon Shot, a joint memoir with Deke Slayton, "they would appear to walk along flat ground, when their legs disappeared and reappeared, like small ships on a heaving sea." It was like trying to find one's way across the featureless expanse of the Sahara Desert. They never reached the rim of Cone Crater, but subsequent analysis determined that they got within about 60 feet (20 meters) of doing so.
Al Shepard, pictured here with the Modular Equipment Transporter (MET), became the oldest man to walk on the Moon and the oldest person to perform EVA at the time. Photo Credit: NASA
Aged 47, Shepard became the world's oldest person to participate in an EVA, a record that he would hold for more than a decade, until STS-6 and the shuttle program's first spacewalk in April 1983. From a public affairs perspective, the final stages of the second Moonwalk were marked by Shepard performing the first golf shot on another world. Using the handle of the contingency sample tool, fitted with "a genuine six-iron," he whacked a golf ball into the distance. The stiffness of his suit meant that he could only operate one-handed, causing him to miss the first shot, whilst the second resulted in a pathetic dribble, but he succeeded on the third attempt. Before launch, Shepard had told Deke Slayton that he would only attempt the stunt if everything else had gone well, and he even sneaked out of crew quarters on a couple of occasions, donned his suit, and practiced his swing.
The final three lunar landings—Apollo 15 in July 1971, Apollo 16 in April 1972, and Apollo 17 in December 1972—saw astronauts Dave Scott, Jim Irwin, John Young, Charlie Duke, Gene Cernan, and Jack Schmitt perform nine Moonwalks, totaling more than 60 cumulative hours on the surface. The missions also featured the Lunar Roving Vehicle (LRV), which enabled far greater distances to be traveled and enabled a broader range of geological sampling activities.
Apollo 15 was also notable in that it featured the only Stand-Up EVA (SEVA) on the Moon, in which Scott opened the lunar module's overhead hatch, stood on the ascent engine cover, and poked his head outside to conduct a 360-degree geological inspection of the landing site. The idea had met opposition from some NASA managers, including Deke Slayton, on the grounds that it would waste valuable oxygen, but Scott countered that it would be invaluable before embarking on his three Moonwalks with Irwin. He pulled a Lunar Excursion Visor Assembly over his helmet and described the 33-minute experience as "rather as if I was in the conning tower of a submarine or the turret of a tank." Meanwhile, Irwin shielded the instrument panel from the harsh lunar sunlight and arranged Scott's oxygen hoses and communications cables to enable him to stand upright. "He offered me a chance to look out," wrote Irwin in his 1973 autobiography, To Rule the Night, "but my umbilicals weren't long enough and I didn't want to take the time to rearrange them."
In the weak lunar gravity, Scott could easily support himself in the hatch on his elbows and employed a bearing indicator and large orientation map to shoot a couple of dozen interconnected stereo photographs of the landing site. "The SEVA was a marvellous and useful experience, for a lot of reasons," Scott later told the Apollo Lunar Surface Journal. "One of our problems at Hadley was that the resolution of the Lunar Orbiter photography was only 60 feet (20 meters), so they couldn't prepare a detailed map. The maps we had were best guesses and we had the radar people tell us before the flight that there were boulder fields—massive boulders—all over the base of Hadley Delta, just boulders everywhere. So another reason for the Stand-Up EVA was to look and see if we could drive the Rover, because if there were boulder fields down there, and nobody could prove there were no boulder fields, it changed the whole picture."
Wearing John Young's red-striped helmet, Ken Mattingly works outside the service module during his Deep-Space EVA. Nearby, Charlie Duke assists from the command module's hatch. Photo Credit: NASA
During the return journeys of Apollo 15, 16, and 17, the Command Module Pilots (CMPs)—Al Worden, Ken Mattingly, and Ron Evans respectively—each performed a "Deep Space EVA" to retrieve camera film from the exterior of the service module. These excursions were done in the "cislunar" environment, about 180,000 miles (300,000 km) from Earth and, to the present day, they mark the farthest spacewalks ever performed. "The EVA itself was kind of unique," Worden recalled in his NASA oral history of his own 39-minute spacewalk, "sort of a unique perspective. I could see the Moon and the Earth at the same time; and if you're on Earth, you can't do that, and if you're on the Moon, you can't do that. It's a very unique place to be!" Since the entire cabin was reduced to vacuum, Scott and Irwin were also required to don their own suits.
Since they were so far from home, the experience was quite distinct from "traditional" EVAs in low-Earth orbit. They were surrounded by the pitchest blackness, and one of the few sources of light was sunlight reflecting off the surfaces of the service module. Irwin considered it strange and eerie from his perch just inside Endeavour's hatch, in silhouette against the full disk of the Moon. "The National Geographic did a painting of me," he wrote in To Rule the Night. "It almost looks like a photo." It is a pity that real photographs of what must have been an absolutely stunning event were never returned.
Such awe-inspiring views can only be described in the words of the men who experienced them. Occasionally, on Apollo 16, Ken Mattingly took a few seconds to look around at the blackness which surrounded him. The apparent absence of stars astounded him, and he was captivated by the view of a crescent Earth and the clear Moon, just 50,000 miles (80,000 km) away. One item which was safely returned by Ken Mattingly during his Deep-Space EVA on Apollo 16 was his wedding ring. In addition to collecting film packages, he was also tasked with gathering experiment packages, but had misplaced his wedding ring inside the command module's cabin and presumed it lost. Fortunately, Charlie Duke spotted it, floating out of the hatch, and Mattingly was able to grab it before it was gone.
By the time the final Apollo crew returned from the Moon in December 1972, a mere 7.5 years had elapsed since history's first spacewalk, and humans had reached and explored the lunar surface and performed EVAs in the cislunar void, betwixt the two celestial bodies. Almost five decades later, no EVAs of such enormous distance have been performed, and it seems unlikely that any will be undertaken for at least the next decade, but they marked a substantial advancement in capability in a very short period. In tomorrow's article to commemorate 50 years of EVA, AmericaSpace will explore the development of tools and techniques to work outside Earth-orbital space stations and how these helped to lay the groundwork for today's International Space Station (ISS).

Copyright © 2015 AmericaSpace - All Rights Reserved

AmericaSpace
For a nation that explores
March 21st, 2015
Operational EVAs: The First 50 Years of Spacewalking (Part 3)
By Ben Evans
The final Skylab mission marked the first occasion on which a spacewalk was conducted on Christmas Day. Photo Credit: NASA
Three weeks have now passed since a trio of Extravehicular Activities (EVAs) took place outside the International Space Station (ISS) to prepare the orbital outpost for a significant period of expansion and hardware relocation in 2015. Astronauts Barry "Butch" Wilmore and Terry Virts spent more than 19 cumulative hours in the vacuum of space, laying cables and utilities, installing the Common Communications for Visiting Vehicles (C2V2) infrastructure, lubricating the 57.7-foot-long (17.6-meter) Canadarm2 robotic arm, and configuring a pair of Common Berthing Mechanisms (CBMs) on the station's Tranquility node. Coming at the dawn of the 50th year since Soviet cosmonaut Alexei Leonov performed humanity's first spacewalk, these excursions continue a long history of astronauts and cosmonauts working outside their pressurized craft to construct and maintain a succession of space stations.
Following the completion of the final piloted voyage to the Moon—recounted in Thursday's AmericaSpace article—the United States' next steps into space were the launch of the Skylab orbital station and its planned occupancy by three long-duration crews throughout 1973 and into the spring of 1974. Original plans for EVAs outside Skylab were relatively minimum in number, and the first crew was expected to spend 28 days aboard the station and astronauts Charles "Pete" Conrad and Joe Kerwin were tasked to perform a single 2.5-hour spacewalk to retrieve photographic film cassettes from the large Apollo Telescope Mount (ATM). All of those plans were cast into disarray, shortly after Skylab's 14 May 1973 launch, when a mishap resulted in the micrometeoroid shield being torn away, along with one of two power-generating solar arrays, and jamming the other with debris, thus virtually crippling the station before its mission had even begun.
Spacewalking took center-stage of the plan to save Skylab. Three possible repair options were developed: placing a sunshade across the exposed hull, erected by means of a long pole, or deploying a sunshade from the hatch of the Apollo command module, whilst station-keeping, or the extension of a sunshade through Skylab's scientific airlock. The third option was ranked least suitable, and teams from NASA's Johnson Space Center (JSC) in Houston, Texas, and Marshall Space Flight Center (MSFC) in Huntsville, Ala., set to work on the others. Underwater evaluations of the sunshades were performed by Kerwin and the mission's backup commander, Rusty Schweickart, in the Neutral Buoyancy Simulator (NBS) at MSFC. "We had to answer certain very basic questions," Schweickart recalled in a March 2000 oral history for NASA. "Could we get physically around to where we had to be? Could we see certain things? These were questions which you couldn't answer just looking at drawings. We had to get into the water, get on the real vehicle and see whether certain things could be done."
Artist's concept of Pete Conrad working with the Beam Erection Tether (BET) to free the clogged solar array. Image Credit: NASA
The remarkable effort to develop the sunshade has been described in another AmericaSpace history article, and the urgent need for the first crew to arrive added further tension. "Just get me up there, goddamn it!" was Conrad's typically to-the-point remark. On 25 May, he, Kerwin, and fellow astronaut Paul Weitz were launched into orbit and after a successful rendezvous with Skylab they set to work. Unlike the Apollo lunar surface suits, the Skylab ensembles lacked a backpack and instead featured an Astronaut Life Support Assembly (ALSA)—a kind of "belly-pack," supported by a leg-mounted emergency oxygen bottle—which provided water, oxygen, and electrical power.
The first EVA kicked off with the opening of the command module's hatch. With Kerwin hanging onto his ankles to provide stability, Weitz reached out and set to work assembling a pair of modified tree loppers and a kind of "shepherd's crook" to free Skylab's jammed solar array. (Under the original flight plan, Weitz had not been scheduled for an EVA during the mission.) Kerwin passed him three sections to assemble a pole, with the loppers at the end, whilst Conrad kept the spacecraft steady, just 24 inches (60 cm) from the station, his view blocked by the open hatch. However, as he worked, Weitz found that his actions were actually moving the command module toward Skylab. "It made for some dicey times," Weitz later told the NASA oral historian. The torrent of four-letter words from the entire crew prompted the Capcom, at one stage, to advise them to modify their language, as they were on an "open-mike." The main problem was that a strip of metal had become wrapped across the solar array system during the separation of the micrometeoroid shield and none of Weitz' efforts to cut the strip had any effect. The EVA ended after 35 minutes.
Although the crew was able to board Skylab and deploy the sunshade, the need to unfurl the jammed solar array proved critical, and a second spacewalk was scheduled for 7 June. Practiced in the NBS by Rusty Schweickart, the 3.5-hour EVA saw Conrad and Kerwin successfully complete this task and restore electrical power to the station. It was a watershed moment in the history of U.S. EVAs. "Before that, there was still the legacy of problems with EVA during Gemini," recalled Schweickart. "Apollo, of course, made a big difference, but that was sort of running around on the [lunar] surface in gravity again. So, here was EVA of a massive scale in weightlessness that we never anticipated; [we] did it with flying colors, everything worked just fine, never had a problem and saved the mission." A third and final EVA on 19 June saw Conrad and Kerwin retrieve photographic films from the ATM.
Al Bean became one of only four humans to have performed spacewalks and Moonwalks. Photo Credit: NASA
The second Skylab crew of astronauts Al Bean, Owen Garriott, and Jack Lousma was assigned to perform three EVAs: the first to load the ATM with film and install a twin-pole sunshade to provide protection, followed by two others to retrieve and reload ATM film. They were also launched into orbit with a six-pack of replacement gyrodynes for redundancy. Unfortunately, circumstances conspired against the crew in the form of space sickness, which delayed the first spacewalk until 6 August 1973. Garriott and Lousma took longer in space than they had in the NBS, and they returned inside Skylab after six hours and 31 minutes. Excluding the Moonwalks of the final three Apollo missions, this established a new world record for the longest EVA at that time.
"The spacewalks are just absolutely the high point," Lousma explained to the NASA oral historian, years later. "It really is the most memorable part of being in orbit; just an unusual experience, in that when you go outside, it's different than being inside. When you're inside, you look through the window and you see part of world." Outside, in the ethereal void, the Earth was an enormous "sphere," just beyond the helmet visor. Lousma was dazzled by the glare of the unfiltered sunlight and was astonished that, for the very first time, he really felt the sensation of speed and motion over Earth. At the same time, however, unlike the related sensations associated with speed in an aircraft, there was no vibration and absolutely no sound. "It's like gliding along on this magic carpet," he said, "going into the sunset and sunrise every hour and a half … doing that for six hours." On one occasion, perched on the end of the ATM, installing a film cassette, Lousma remembered moving into orbital night, somewhere over Siberia, he guessed, and being thrown headlong into blackness. Through his visor, he could hardly see his own gloved hands and had the profound realisation that "it's just me, God, the spacecraft and my buddies and that's it!"
Two weeks later, on 24 August, Garriott and Lousma were outside for the second EVA of the mission to install the six-pack of gyrodynes. In his diary—preserved in the book Homesteading Space: The Skylab Story, by David Hitt, Joe Kerwin, and Garriott—Al Bean noted that it was a tough decision determining which tasks would be completed by which crewman. As the physically strongest, Lousma would do the gyrodyne installation ("If anyone can twist those connectors that had never been designed to be loosened in flight," Bean wrote, "Jack was the man") and the EVA ran like clockwork for 4.5 hours. During the occasional quiet spell, Garriott managed to glance at the panorama "beneath" him and beheld the snow-capped Andes Mountains, stretching toward Peru, and strained to see further toward Tierra del Fuego.
In the hectic 10 days between the launch of Skylab and the launch of Pete Conrad's crew, NASA and its contractors rose spectacularly to one of the greatest challenges in their history. In the water tank at the Marshall Space Flight Center, astronauts Rusty Schweickart and Ed Gibson practice repair techniques. Photo Credit: NASA
The third and final EVA occurred on 22 September, shortly before the crew's return to Earth. This time, Bean—making his first "spacewalk," having previously performed two Moonwalks on Apollo 12—and Garriott spent almost three hours retrieving ATM film. Bean's decision that he should be part of the EVA was down to a feeling that Lousma would probably fly again and perform another spacewalk, whereas Garriott probably would not. (As circumstances transpired, none of them ventured outside the pressurized confines of their craft again in their astronaut careers.) In establishing both spacewalks and Moonwalks under his belt, Bean became one of only four humans to have done so. From his lofty position, high above the roof of the world, he was exultant. At one point, he kicked himself out of his foot restraints on the ATM and spun himself into a handstand. Years later, he convinced himself that he had set a new world record handstand for both height and speed.
With the return to Earth of Bean, Garriott, and Lousma, the final Skylab crew—comprising astronauts Gerry Carr, Ed Gibson, and Bill Pogue—were tasked with performing as many as five EVAs during their mission. These were expected to begin a week after their mid-November 1973 launch with the loading of ATM film, then be followed by the installation of external experiments, observing Comet Kohoutek, and retrieving film.
The first EVA, lasting 6.5 hours, was performed on 22 November, Thanksgiving Day, and saw Pogue and Gibson successfully load the ATM and checking and repairing an inoperable antenna. Their pressurized suits, Pogue remembered, were hard to work with, particularly in view of the reality that the astronauts' spines lengthened slightly after a few days in weightlessness. "Our space suits had been very carefully custom-fitted … so when we got up in space and our bodies increased in length, it was not only difficult to get into them, but you got back after working six or seven hours outside [and] you'd have cable burns on your shoulders because, from crotch to shoulder, you'd grown two inches and that put a lot of pressure on the shoulders."
The second spacewalk—and the only one ever to have taken place on the traditional date of Christ's birth—occurred on 25 December and saw Carr and Pogue photographing Comet Kohoutek. Pogue carefully set up his camera, mounting it onto a strut and positioning it such that one of Skylab's ATM arrays barely blocked the Sun. He could not physically see the comet, but Mission Control had earlier sent him a diagram on the teleprinter. "The instructions were clear and it was a fairly easy job," he recalled. "I turned on the camera and I was finished." For Carr, who was making his first career EVA, the biggest surprise was that he did not need to urinate throughout the seven hours that he was outside the space station. "I was amazed when I got back in, because I expected that I'd have to go to the bathroom something fierce," he told the NASA oral historian, years later. "Apparently, I'd gotten rid of a lot of fluids in the form of sweat through my pores. When I got back in, I was really sweaty, but I really didn't have to urinate."
The salvation of Skylab, perhaps more so than any previous endeavor, validated the importance of Extravehicular Activity (EVA). Photo Credit: NASA
This was Pogue's final EVA and he made the most of it. "I crawled all over the accessible parts of Skylab," he recalled. "It reminded me of when I was a kid, doing a mud-crawl in a four-feet-deep stock tank used for watering cows and horses." Returning inside Skylab after seven hours and three minutes, they had eclipsed the previous crew and established a new empirical single-EVA record. Four days later, on 29 December, Carr and Gibson spent 3.5 hours outside, acquiring yet more Kohoutek photography, and also embarked on a final spacewalk on 3 February 1974 to retrieve ATM film. The crew returned to Earth a few days later, closing the book on the Skylab era and marking the last EVA by U.S. astronauts until the dawn of the shuttle era.
However, the absence of U.S. spacewalkers from the scene throughout the remainder of the 1970s also made way for three Soviet EVAs from the Salyut 6 space station. Not since the excursion of Alexei Yeliseyev and Yevgeni Khrunov in January 1969 had cosmonauts departed their craft in orbit, but this changed in December 1977 when Yuri Romanenko and Georgi Grechko spent 88 minutes inspecting Salyut 6's docking mechanism for damage. During this activity, a particularly hairy event transpired. "It is claimed," wrote Soviet space historian Phillip Clark, "that Romanenko fancied a taste of spacewalking experience and slowly left the transfer compartment." This story gained an ominous note when related in the Western press, partly due to Grechko's misunderstood joke that his partner was on the verge of being "lost" in space. Romanenko's electrical and communications umbilicals would have kept him from drifting away from Salyut, but according to David Portree and Robert Treviño in Walking to Olympus, Romanenko "was very angry about the story," since it implied that he had acted irresponsibly.
Several months later, in July 1978, cosmonauts Vladimir Kovalyonok and Aleksandr Ivanchenkov spent two hours outside Salyut 6, retrieving external experiments. Portree and Treviño noted that during one period of orbital darkness, the spacewalkers were treated to a brilliant meteor, burning up "beneath" them in the upper atmosphere, and that the pair photographed areas of the Black Sea, Kazakhstan, and China, then watched as Australia and its Great Barrier Reef passed beneath them. The final Salyut 6 EVA took place in August 1978 and saw cosmonauts Vladimir Lyakhov and Valeri Ryumin perform a contingency excursion to cut free a troublesome antenna.
By the end of the 1970s, a decade and a half had elapsed since humanity first pushed open the hatch and ventured from a spacecraft and into the harsh radiation and vacuum environment beyond. During that span, nine Soviet cosmonauts and 29 U.S. astronauts had spent periods of between 12 minutes and more than seven hours in the most hostile conditions ever encountered, testing maneuverability, building, repairing and installing hardware, and walking on the surface of the Moon. Their ages had ranged from just 30 years, in the case of Alexei Leonov, to 47 years, in the case of Al Shepard. With the 1980s and beyond, the envelope would be pushed yet further with the shuttle era, the Salyut 7 and Mir orbital outposts, and today's International Space Station (ISS).

Copyright © 2015 AmericaSpace - All Rights Reserved

AmericaSpace
For a nation that explores
March 22nd, 2015
Repair and Salvage: The First 50 Years of Spacewalking (Part 4)
By Ben Evans
During his historic untethered EVA with the Manned Maneuvering Unit (MMU) on 7 February 1984, Bruce McCandless ventured as far as 300 feet (90 meters) from Challenger. Photo Credit: NASA
Ironically, the spacecraft from which the most Extravehicular Activities (EVAs) were performed—the space shuttle—was not originally intended to carry the capability for spacewalking at all. "The NASA perspective of a shuttle was an airliner," explained space suit engineer Jim McBarron in an oral history, "and the people inside it wouldn't need suits." It was only through prompting and questioning of senior management, when faced with the need to have a contingency capability to close the orbiter's payload bay doors, that an EVA requirement was implemented. From the first spacewalk conducted outside the shuttle in April 1983 until the last in July 2011, 163 discrete EVAs have seen astronauts from the United States, Russia, Japan, Switzerland, Canada, France, Sweden, and Germany test jet-propelled backpacks, salvage and repair satellites and space telescopes, deploy and retrieve experiments, and build the International Space Station (ISS).
As described in yesterday's AmericaSpace article, substantial advances in EVA techniques and technologies had already been accomplished before the first shuttle mission got underway in April 1981. Notably, 12 men had walked on the Moon, three had walked in "cislunar space," and one had performed a Stand-Up EVA (SEVA) to gain a 360-degree perspective of his landing site. Astronauts had evaluated their locomotion in the peculiar microgravity environment, and, aboard Skylab, they had demonstrated that they could embark on complex tasks to save entire missions. With the advent of the shuttle era, EVA was expected to take center-stage, and, in mid-1982, NASA announced plans for an ambitious mission to retrieve, repair, and deploy back into orbit the damaged Solar Maximum Mission (SMM or "Solar Max") observatory in early 1984.
On STS-5 in November 1982, the fifth flight of Shuttle Columbia, it was intended that an almost nine-year hiatus in U.S. spacewalking activity would come to an end with a 3.5-hour EVA by astronauts Bill Lenoir and Joe Allen. In addition to testing the new shuttle-specification space suits and rehearsing techniques for manually closing the payload bay doors, they would have tested tools for the Solar Max repair, including fixed and torsion-adjustable bolts, a special wrench, and a dummy Main Electronics Box (MEB) for the satellite's coronagraph. Unfortunately, the EVA was postponed by 24 hours, when Lenoir and STS-5 Pilot Bob Overmyer suffered a severe bout of space sickness, and an attempt to perform the spacewalk the following day came to nothing when a problem was encountered with a ventilation fan on one of the suits and a pressure shortfall in the primary oxygen regulator of the other suit. Several of the helmet-mounted floodlights also failed to operate correctly, and, following fruitless attempts to troubleshoot the problems, the EVA was canceled and subsequently rescheduled for the next mission, STS-6.
Originally, the shuttle was intended never to require an EVA capability. In the 1970s, it was regarded as the spacegoing equivalent of a commercial airliner … but when it became clear that problems might be experiencing closing the payload bay doors and attending to other technical issues, an EVA capability evolved. Many of the techniques for attending to contingencies would have been trialed by Lenoir and Allen on STS-5. Photo Credit: NASA
"I guess I was the bad guy," STS-5 Commander Vance Brand told the NASA oral historian. "I recommended to the ground that we [cancel] the EVA, because we had a unit in each space suit fail in the same way. It looked like we had a generic failure there. It was the first time out of the ship. We didn't want to get two guys—or even one guy—outside and then have [another failure]. We could have taken a chance and done it, but we didn't. I'm not sure Bill Lenoir was ever very happy about that, because he and Joe, of course, wanted to go out and have that first EVA."
In December 1982, NASA announced that the EVA would be attempted by astronauts Story Musgrave and Don Peterson on STS-6, the maiden voyage of Shuttle Challenger, which eventually launched in April 1983. "It didn't give us much time to train," Peterson recalled in his NASA oral history. "I didn't have much experience in the suit, but the advantage we had was that Story was the astronaut office's point of contact for the suit development, so he knew everything there was to know. He'd spent 400 hours in the water tank, so he didn't really have to be trained!" By his own admission, Peterson's EVA training for STS-6 "was pretty rushed." He recalled being underwater in the Weightless Environment Training Facility (WET-F) at the Johnson Space Center (JSC) in Houston, Texas, on 15-20 occasions, "and that's not really enough to know everything you need to know."
Unlike previous Apollo space suits, the modularized shuttle ensemble, with its waist closure ring, eliminated the need for pressure-sealing zips and therefore had a much longer shelf life. Additionally, the use of newer, stronger, and more durable fabrics enabled space suit engineers to design joints with better mobility, resulting in lower weight and a reduction in overall cost. On 6 April 1983, they opened the outer airlock hatch into Challenger's payload bay and—with Musgrave aged 47 and Peterson aged 49—became the oldest men at that time ever to embark on an EVA.
During their 4.5 hours outside, the astronauts evaluated their movement, tested the tools to manually close the payload bay doors, and rehearsed procedures for the Solar Max repair. Yet the experience of being disconnected from their spacecraft was profound. "You remember little things like sound," Musgrave told a post-flight press conference. "Even though there's a vacuum in space, if you tap your fingers together, you can hear that sound because you've set up a harmonic within the space suit and the sound reverberates within it. I can still 'hear' that sound today. But the main impression is visual: seeing the totality of humanity within a single orbit. It's a history lesson and a geography lesson; a sight like you've never seen."
The Manned Maneuvering Unit (MMU) was first trialed by Bruce McCandless on Mission 41B in February 1984. Photo Credit: NASA
One of the critical elements of the Solar Max was the Manned Maneuvering Unit (MMU), a jet-propelled backpack, developed by Martin Marietta, which would allow spacewalkers to fly "untethered" to great distances from the shuttle. Its first test flight was planned for shuttle Mission 41B in February 1984 and featured astronauts Bruce McCandless—who had played a pivotal role in the development of the MMU—and Bob Stewart flying it as far as 300 feet (90 meters) into the inky blackness. This cleared a significant hurdle for the retrieval and repair of Solar Max in April by the crew of Mission 41C. Despite initial difficulties, spacewalkers George "Pinky" Nelson and James "Ox" van Hoften and their crewmates Bob Crippen, Dick Scobee, and Terry Hart succeeded in capturing and repairing Solar Max and boosted it back into its operational orbit.
As the Americans got back into the business of EVA, the Soviets did likewise. Following the launch of their Salyut 7 space station, cosmonauts Anatoli Berezovoi and Valentin Lebedev performed a spacewalk in July 1982, working with the connection of pipes and girders to practice methods for the augmentation of the solar arrays. This augmentation was to be carried out during a series of EVAs by cosmonauts Vladimir Titov and Gennadi Strekalov, but when they almost lost their lives in a harrowing launch abort in September 1983 the task fell partly to the incumbent Salyut 7 crew of Vladimir Lyakhov and Aleksandr Aleksandrov. On 1 November, the two men ventured outside the station to begin a task for which they had not specifically trained, and, in doing so, Lyakhov became the first Soviet cosmonaut to make a second EVA. During their two hours and 50 minutes outside, the two men carefully attached an auxiliary solar power to one side of Salyut 7's dorsal array, then unfurled it to its full length of 16 feet (5 meters). Two days later, on 3 November, they were back outside for almost three hours and successfully installed a second auxiliary panel.
The following year, 1984, saw many spacewalking records fall to the Soviets. In a four-week period from 23 May to 19 May, cosmonauts Leonid Kizim and Vladimir Solovyov performed no less than five EVAs—an achievement equaled only by U.S. astronaut Dave Scott at that time—to tend to a troublesome propellant leak and further augment Salyut 7's solar arrays. In doing so, the two men also became the first Soviet cosmonauts to perform in excess of three EVAs. The rate at which these spacewalks were performed necessitated a rapid-fire series of Progress resupply vehicles, three of which were launched in a six-week period, to replenish the oxygen expelled overboard from the airlock.
Mission 41C put the shuttle's capabilities to the test. In a single flight, the reusable vehicle demonstrated its capacity to support satellite deployment and retrieval, rendezvous, and proximity operations, untethered spacewalking and robotics … and served as a highlight of the ingenuity of the human spirit. Photo Credit: NASA, via Joachim Becker/SpaceFacts.de
NASA had already announced plans for Kathy Sullivan to become the first female spacewalker on Mission 41G in October 1984, and it was seen as no coincidence that the Soviets pipped them to the post by launching Svetlana Savitskaya to Salyut 7 in July. Whilst aboard the station, Savitskaya and fellow cosmonaut Vladimir Dzhanibekov spent almost four hours in vacuum, testing a universal hand tool for cutting, welding, soldering, and brazing. Finally, in August, Kizim and Solovyov performed the sixth EVA of their expedition to tend to an oxidizer leak, wrapping up their final spacewalk, after a cumulative 22 hours and 50 minutes outside Salyut 7. They had performed more EVAs than any single astronaut or cosmonaut in history and, in a single flight.
Less than three months after Savitskaya's voyage, in October 1984, Challenger launched on Mission 41G, one of whose tasks was a 3.5-hour EVA by Dave Leestma and Kathy Sullivan to evaluate hardware for the future refueling of satellites in low-Earth orbit. Mounted at the rear end of the shuttle's payload bay was the Orbital Refueling System (ORS), containing highly toxic hydrazine, some of which the spacewalkers would transfer between a pair of spherical tanks. Upon venturing outside, Leestma described the experience to Henry S.F. Cooper, Jr., for the 1987 book Before Lift-Off, as "like the difference between sitting at a desk in a big room and sitting at a desk in the middle of a prairie." After the flight, the surgeons told him that his electrocardiogram reading went exceptionally high. During the course of EVA, six hydrazine transfers were successfully completed.
America's next spacewalks occurred just a few weeks later, in November, when Mission 51A astronauts Joe Allen and Dale Gardner embarked on the final voyage of the MMU to successfully retrieve the Palapa-B2 and Westar-VI communications satellites and bring them back to Earth for refurbishment and reuse. Both satellites had been launched earlier in the year, but a booster malfunction had left them in lower than intended orbits. In the year prior to the catastrophic loss of Challenger, two other shuttle crews—Mission 51D in April 1985 and Mission 51I in August—were tasked with performing EVAs to repair orbiting communications satellites. Both missions put the skill and ingenuity of astronauts and flight controllers to the test. On Mission 51D, astronauts Jeff Hoffman and Dave Griggs performed the first unplanned EVA of the shuttle era, unsuccessfully attempting to use a makeshift fly swatter to activate a deployment switch on the Syncom 4-3 satellite. Four months later, Mission 51I spacewalkers James "Ox" van Hoften and Bill Fisher executed a pair of spectacular EVAs in which they revived the satellite and sent it back into orbit.
The story behind the 51I spacewalks is an indicator of the seemingly bulletproof attitude that pervaded much of NASA in the months preceding the loss of Challenger. Van Hoften and his 51I crewmate Mike Lounge were both on alert status with the Air National Guard in April 1985, when they learned of the Syncom failure. They immediately started swapping ideas about how to solve it. "Back then," van Hoften told the oral historian, "there was a much more can-do spirit at NASA and everyone felt like, hey, you can do anything." The space agency's management was sufficiently impressed to send the crew to Hughes Aerospace—the satellite's prime contractor—to lay out their plan. The company's president was so impressed with van Hoften's presentation that he immediately called NASA Administrator Jim Beggs to invest $5 million in the salvage effort.
In a triumphant ending to a triumphant space salvage, James "Ox" van Hoften strikes a Charles Atlas pose on the end of the shuttle's RMS mechanical arm, seemingly hoisting the world on his shoulders. Photo Credit: NASA
Less than eight weeks before the launch of Challenger on her final, fateful voyage, the crew of Mission 61B performed two EVAs to support the construction of hardware in readiness for NASA's proposed Space Station. The Experimental Assembly of Structures in EVA (EASE) was an inverted tetrahedron of interconnected tubes, whilst the Assembly Concept for Construction of Erectable Space Structures (ACCESS) comprised a 43-foot (13-meter) "tower," both to be assembled in the shuttle's payload bay. Following its conception in 1984, the EASE-ACCESS task jumped across several missions on the shuttle manifest, before settling on Mission 61B and being assigned to a pair of first-time spacewalkers named Jerry Ross and Sherwood "Woody" Spring.
Over a period of several months, the two men worked with the EASE-ACCESS team to choreograph a pair of six-hour EVAs to assemble the structures, whilst encased in pressurized space suits. "Both crew members were in fixed foot restraints," said Ross in a NASA oral history interview, describing the ACCESS assembly task. "It was basically just a matter of bringing a part out, putting it onto this assembly fixture, hooking the components together, rotating to the three faces, then sliding the completed segment of truss up, and repeating the process for a total of 10 'bays'. We knew that that technique would be a very satisfactory way of doing business, because when a crew member's feet are anchored properly, that gives you both hands free to do work." EASE, on the other hand, was more problematic, since one of the men would be positioned, free-floating, without foot restraints, at the "top" of the structure, holding on with one hand and torquing the beams into position with the other. Lessons from earlier EVAs had already proven that the absence of foot restraints and adequate hand holds made it extremely difficult for spacewalkers to steady themselves and perform tasks. In two highly successful spacewalks on 29 November and 1 December 1985, Ross and Spring triumphantly built the EASE-ACCESS framework.
Returning inside the airlock of Shuttle Atlantis, Ross could hardly have imagined that calamity would soon before the program and that the next U.S. EVA would be more than five years into the future. He could also hardly have known that he would be the next American to perform a spacewalk and, in his wildest dreams, would have struggled to accept that a little over a decade hence, in December 1998, he would be assembling components for the real-life International Space Station (ISS) in orbit.

Copyright © 2015 AmericaSpace - All Rights Reserved