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Hanging by a thread: racing to the first spacewalk Soviet and American astronauts were kept on a short leash.

Access to a "lifeline" offers additional security to contestants on the television game show Who Wants To Be a Millionaire. When invoked, telephonic contact tethered the in-studio player with an informational resource--someone who might keep the contestant in the game with a winning answer.

In 1965 a different kind of lifeline allowed Soviet cosmonaut Aleksei Leonov to "walk in space" and win another round in the Space Race for the USSR. On March 18th of that year, Leonov and mission commander Pavel Belyayev activated an inflatable airlock that extended from the side of their orbiting spacecraft, Voskhod 2. After Leonov readied his space suit, he sealed the connection to the space capsule, opened the exit port, and slipped into space 206 kilometers (128 miles) above Earth. Tethered on a safety line containing telemetry and telephone cable, he became the world's first spacewalker.

Leonov had enough rope to drift 41/2 meters (15 feet) from the ship. Breathing oxygen from a backpack, he stayed outside for 10 minutes, collided with the capsule five times, and returned to the airlock.

His achievement prompted the worldwide applause that Soviet premier Nikita Khrushchev had intended. Exploits in space had propaganda value, and Khrushchev pressured his research and engineering teams to develop their space program around showcase missions, even if it meant adding questionable risk.

Leonov's spacewalk was much riskier than the world knew. Extravehicular activity (EVA) is not easy. Walking in space has been likened to walking underwater at the bottom of a pool. Although the experience is exhilarating, the effort is exhausting. Because Leonov was a pioneer, he couldn't anticipate everything that would happen, and he nearly didn't make it back into the airlock.

When Leonov pulled himself back to the spaceship with his line, he discovered that he couldn't get back inside. With less than an hour of air left in his tank, he realized his peril. Pressurization had made his suit too stiff, and he couldn't bend to reenter. His heartbeat raced, but avoiding panic he risked incapacitating himself with the bends and reduced the pressure in his suit by a third. With greater flexibility he managed to wriggle in, close the port, and repressurize the compartment--drenched in perspiration but safe. Notwithstanding his lifeline, he almost lost his life.

Because Leonov's dangerous extravehicular exercise was not accurately reported by Soviet sources, the American space program was accelerated to match that of the Soviets, with a US spacewalk just three months later. Forty-one years ago, on June 3, 1965, Edward White stepped out of the hatch from the depressurized cabin of Gemini 4. At the end of a 7 1/2-meter tether, he orbited Earth with his spaceship like a balloon on a string.

White's lifeline was more like an umbilical cord, nourishing him with oxygen and supplying electrical power. Besides rambling through the skies on a longer leash than Leonov, White also had a "zip gun," or Hand-Held Self-Maneuvering Unit. With a blast of compressed air, White propelled himself around the capsule. He emptied the gun's chamber in four minutes, however, and for the rest of the EVA he used the tether to pull himself around the spacecraft. According to White, "The tether was quite useful. I was able to go right back to where I started every time, but I wasn't able to maneuver to specific points with it."

After the EVA, when White and Gemini 4 commander James McDivitt were getting ready to repressurize the cabin, they had difficulty closing and locking the hatch. No longer tethered, White nearly floated out into space again, and McDivitt, grabbing White's legs, became his lifeline.

Subsequent Gemini flights demonstrated the difficulty of tethered spacewalks. The tether was not really cooperative or entirely predictable. It coiled around the astronaut and sometimes kept him from getting where he wanted to go.

Eugene Cernan, the second American astronaut to walk in space, described how he reached the end of his tether in The Last Man on the Moon (1999). In Chapter 13, "The Spacewalk from Hell," he wrote, "I felt as if I was wrestling an octopus. The umbilical cavorted with a life of its own, twirling like a ribbon, trying to trap me like a cord winding around a window shade." He fought it for 20 minutes and then decided the "snake was perhaps the most malicious serpent since the one Eve met in the Garden of Eden."

Despite the complications of umbilical dynamics in space, NASA didn't want to lose any astronauts overboard and so required tether use on all Gemini flights.

Tethered adventures in space had been imagined by space visionaries decades before space-suited astronauts performed outside the box. We encounter them as early as the 1920s, in an illustration in Max Valier's The Push into Space. Thirty years later, space artist Chesley Bonestell put spacewalking astronauts into paintings for Collier's magazine and in Walt Disney's 1956 television show Man in Space, whose spinoff comic books also featured spacemen with strings attached.

A tense and dramatic scene in George Pal's 1950 film Destination Moon puts Moon-bound astronauts out on the hull of their spaceship to inspect an undeployable radar antenna. Reaching the end of his safety rope, one of them lets it go to take a closer look at the rocket's exhaust nozzle. As the magnetic soles of his shoes inadvertently become detached from the hull, he drifts away. Floating helplessly from the ship, out of reach of the lifeline thrown to him, he is finally rescued when one of the other crewmembers turns an oxygen tank into a handheld maneuvering unit and retrieves the lost scientist.

Notwithstanding pseudoscientific claims that falsely make an ancient astronaut--blasting into space--out of a Maya king shown dying on his stone sarcophagus at Palenque, Mexico, the ancient Maya lords did tether themselves to the sky with celestial umbilicals. Rather than walking in space, they were ruling on Earth, and they believed that part of their power and authority was conferred to them by the heavens. The double-headed serpent bars they carried symbolized the ecliptic--the path on which the Sun, Moon, and planets travel through the sky. Tethered to that high road, those celestial gods communicated their divine intent to the rulers below. Monitoring their movements, the Maya kings believed that the ecliptic was their lifeline to answers from the gods.

E. C. Krupp answers to everybody without a lifeline at Griffith Observatory in Los Angeles.
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Title Annotation:Aleksei Leonov
Author:Krupp, E.C.
Publication:Sky & Telescope
Geographic Code:4EXRU
Date:Jun 1, 2006
Words:1069
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