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First Skylab crew: Saving America's space station

Anatoly Zak, Spaceflight Correspondent
May 30, 2016, 22:31 UTC

Sen—After the political goal of the Apollo program had been fulfilled in 1969, the American lunar exploration effort ended three years later with the successful landing of Apollo-17. Realizing early on that funding levels of the Apollo era could not be sustained for long, NASA looked for various ways to utilize the awesome legacy of the Moon Race for less ambitious goals.

Ultimately, "retreating" to low Earth orbit for a multi-purpose scientific mission emerged as a worthy and affordable pursuit for the post-Apollo missions. Relying heavily on the left-over hardware, NASA decided to launch its first long-duration outpost in space, which was imagined decades earlier by many pioneers of space exploration.

After some consideration whether to have astronauts to outfit their own home in space inside an empty rocket booster, NASA favored the launch of a fully functional space station dubbed Skylab on the very last available Saturn-5 rocket. The giant oxygen tank of the rocket's third stage, which during Apollo had been used to push the Apollo spacecraft toward the Moon, was reconfigured to accommodate spacious living quarters and a laboratory. What used to be a fuel tank at the bottom of the stage would now serve as a waste container. At the top of the propellant compartment, engineers fitted an airlock, which was a leftover from the Air Force's cancelled Manned Orbital Laboratory, MOL.

Finally, the former lunar cargo of the rocket was replaced with a large telescope module customized for the studies of the Sun and with a docking compartment with two ports for visiting Apollo spacecraft, which were scheduled to deliver at least three expeditions to the station.

Though it had reached the launch pad almost two years after the Salyut-1 space station, NASA's 90-ton Skylab dwarfed its 20-ton Soviet predecessor.

An unmanned Saturn-5 rocket carrying Skylab lifted off from Cape Canaveral on May 14, 1973. The mission was designated SL-1. The SL-2 mission with the first crew for the station was also ready for liftoff on a two-stage Saturn-1B rocket from a near-by pad.

However, just 63 seconds after liftoff, as the Skylab was still accelerating through the dense atmosphere, ground controllers saw signals indicating unscheduled deployment of the micro-meteoroid shield and one of solar panels on the exterior of the outpost.

Fortunately, the rocket still successfully inserted its cargo into orbit, but it was evident that NASA's first space station had suffered damage during the ascent. There was only little power coming from one of the two main solar arrays on the station and the temperature onboard was rising alarmingly fast.

The first crew was grounded for the time being, while NASA tried to understand what exactly happened and whether it would be possible to salvage Skylab.

As it soon transpired, the station's micro-meteoroid shield, which also doubled as thermal cover, along with one of the two solar panels was sheered off during launch, while a piece of debris likely held the second panel in folded condition.

Within days, resourceful engineers improvised several plans for the first crew to manually deploy the surviving solar panel and to install a makeshift thermal shade.

After a 10-day delay, the first Skylab crew, including Commander Charles Conrad, Pilot Paul Weitz and Scientist Pilot Joseph Kerwin, lifted off from Cape Canaveral on May 25, 1973, at 9 a.m. EDT.

Some eight hours later, the command and service module of the Apollo spacecraft approached the stricken outpost, reviewed the exterior and made a berth at the station for a short break. Astronauts confirmed that a strap probably from the ripped meteoroid shield entangled the remaining solar panel preventing it from proper deployment.

Because there were no handrails or fixtures near the solar array, Conrad then undocked and maneuvered the Apollo to hover over the problematic location. Weitz then stuck his upper torso from an open hatch and tried to reach the obstruction on the panel with a 10-foot hook. Inside the cabin, Kerwin kept Weitz by his legs to prevent him from floating out. However all their attempts to free the panel were fruitless. Moreover, repeated pulling action triggered the space station's stabilization system to fire thrusters to keep the lab in position, while Conrad struggled to keep the Apollo from colliding with the Skylab.

The crew finally abandoned the effort and tried to re-dock at the station. That also turned into a struggle and required the astronauts to depressurize the command module and re-assemble the docking mechanism. Only then did the docking at Skylab succeed and the exhausted trio could take a well-deserved rest.

The next day, Weitz donned a gas mask and ventured into the overheated interior of the station. Fortunately, he found no toxic gases in the atmosphere and his crew mates could follow him into the roomy interior. The main section was much hotter than normal, but not intolerable.

First order of business was to install an improvised umbrella-like sunshade on the exterior of the station through a small airlock originally designed for taking experiments into the vacuum of space. The improvised operation was successful and produced an immediate effect, even though, the crew still spent the first few nights in the much cooler docking section rather than in their dedicated sleeping quarters in the main volume of the lab.

On June 7, after days of careful rehearsals on the ground and in space, Conrad and Kerwin used the spacewalk airlock to exit the station, where they assembled a special cutting device which, after considerable struggle, was successfully used to free and deploy the jammed solar array.

Finally, the crew could enjoy their life in space and focus on the original scientific tasks. The astronauts conducted medical experiments, observed the Sun and monitored the Earth's surface.

By mid June they beat the standing flight duration record set by the crew of the Soyuz-9 mission.

After the planned 28 days in space, the Apollo command and service module undocked from Skylab on June 22, 1973, and successfully splashed down in the Pacific Ocean at 9:49 a.m. EDT around 800 miles off San Diego.

NASA's space station remained in orbit healthy and open for future crews.