Monday, May. 28, 1973
Skylab: The $2.5 Billion Salvage
"Skylab 1 is the last Skylab. It's also the first Skylab. So we do not have the maturity behind the hardware that Apollo had. We fully expect that some problems will come up and bite us."
--Skylab Program Director William Schneider at a pre-launch briefing.
SCHNEIDER'S words proved more grimly prophetic than he could have imagined. Indeed, for a few days last week, it appeared that the failure of an essential protective shield shortly after launch had touched off a chain of events that would result in disaster for the entire $2.5 billion program. But at week's end, as the crippled Skylab continued to orbit the earth, a combination of space-age teamwork and old-fashioned Yankee ingenuity on the part of NASA raised hopes that the mission could yet be salvaged. In fact, the mishap and the bold reaction to it promised to elevate a relatively monotonous experimental flight into high adventure in space.
This week, for the first time in the history of space flight, astronauts are scheduled to be sent into orbit for the express purpose of performing a major repair on a stricken ship. If all goes according to plan, Skylab's three crew members will be launched this Friday (at 9 a.m., E.D.T.) from Cape Kennedy in the same Apollo command ship that was to have carried them up to join Skylab last week. After nearly five revolutions around the earth, Astronauts Charles ("Pete") Conrad Jr., Joseph Kerwin and Paul Weitz will rendezvous with the space laboratory, examine it and attempt two essential repairs: 1) replacing the lost section of Skylab's meteoroid and heat shield with a huge sunshade in an effort to lower the ship's scorching internal temperatures; 2) extending the vital, electricity-producing solar wing apparently jammed by the shield as it ripped away. If the astronauts succeed with these improbable assignments performed outside their craft some 270 miles above the earth, they could then set up housekeeping inside the space lab and complete their original 28-day mission. There is even a good chance that two other teams of astronauts, each slated to spend 56 days in orbit later this year, might be able to live and work aboard Skylab.
The high hopes for saving Skylab contrasted sharply with the earlier gloom that settled over the space community. Barely a minute after Skylab's launch atop a surplus Saturn 5 moon rocket, tiny sensors on the arms of the shield alerted flight controllers to serious problems. Apparently unable to withstand the intense vibrations after liftoff, some and possibly all of the thin shielding around Skylab's Orbital Workshop section suddenly ripped free. As it tore away, it apparently caused one of the twin solar wings on the Orbital Workshop to extend prematurely;
NASA believes the extended wing was then sheared away by the high G-forces on the accelerating rocket. Perhaps because they were not quite sure of the telemetry, NASA spokesmen gave no public hint of any problems. Everything was looking "super good," reported Flight Director Don Puddy.
By the time Skylab reached orbit, NASA controllers were sure that it was in trouble. As the 85-ton spacecraft began circling the earth, it jettisoned its protective shroud, moved its telescope mount into place and unfolded the four windmill-like solar wings that sit above it. But indications were that the remaining solar wing on the Orbital Workshop could not swing out more than a few degrees from the ship and was thus not able to unfold its light-gathering panels. That was bad news indeed. It meant that Skylab was deprived of more than half its electrical power. Even if the astronauts were sent up to Skylab, the serious energy crisis in space would force them to curtail many key experiments, including some of the critical medical tests of bodily functions in conditions of prolonged weightlessness.
Fierce Heat. The worst was still to come. Without the shield, temperatures inside the Orbital Workshop--site of the crew quarters--soared dramatically, climbing to 130DEG F. and higher. The fierce heat endangered the foodstores, especially the new gravy-rich dishes of which NASA is so proud. It may well have fogged sensitive film and ruined medical supplies. There was also danger that the extreme heat would begin to decompose the Styrofoam insulation in the spacecraft's walls, producing potentially lethal gases inside the workshop. Finally, as the temperature of the unprotected aluminum "bald spot" on Skylab's exterior rose to 325DEG, engineers feared that the skin itself might buckle or even rupture.
As the extent of the damage became clear, there were angry recriminations within NASA. Officials feared that the monumental goof would goad Congress into cutting off funds for manned space flight. TIME Correspondent John Wilhelm subsequently learned that the troublesome shield was new and untried, and had repeatedly caused problems during its development. Parts had failed at least four different tests. The shield was apparently plagued by an extreme flutter when subjected to the stresses of launch. Though aware of the shield's shortcomings, NASA decided to use it anyway, mainly to save a few million dollars in additional development costs. Admits Christopher Kraft Jr., director of Houston's Johnson Space Center: "We had a great battle whether we should put that thing on there or not. It was a judgment factor."
While NASA engineers and flight controllers struggled desperately to save the mission, conditions aboard Skylab deteriorated and the launch of the three astronauts was delayed. First priority was given to finding a way to cool off the Orbital Workshop (other sections of the spacecraft remained at a normal 65DEG or 70DEG). Maneuvering the spacecraft with its thrusters, flight controllers in Houston turned the exposed area away from the sun. But by doing that they also changed the angle of the four working solar wings, which reduced their exposure to sunlight and dangerously lowered the production of electrical power.
After two days of experimentation, mission controllers found a compromise position for Skylab. When it was tilted so that its solar panels were at an angle of 55DEG to the direction of the sun's rays, adequate power was produced and the temperature in the Orbital Workshop stabilized close to a tolerable 105DEG.
At the Marshall Space Flight Center in Huntsville, Ala., and in Houston and Cape Kennedy, scientists and engineers held round-the-clock meetings and nation-spanning conference calls to discuss possible repair techniques. One proposal was to have an astronaut poke a giant umbrella-like device out of a hatch and open it above the bald spot.
Others suggested inflating a balloon to shade the craft, or spray painting the affected area. Eventually, NASA seemed to be settling on a different solution: the astronauts would try to shield Skylab with a tissue-thin, aluminized sail-like sheet of Mylar, a plastic film.
To put that plan into operation, the astronauts will maneuver their Apollo command ship within a few feet of the crippled space lab, circle it to inspect the damage, and transmit TV pictures down to earth. Then, after a respite, the astronauts will don their pressure suits and Kerwin will emerge part way from the command-module hatch. Using a pole with cutting shears at its far end (hastily being designed and built at Huntsville), he will try to trim away any debris around the root of the ripped-off solar wing or elsewhere. He will also attempt to swing out the intact wing.
Two Tries. Attaching the sunshade will be even more difficult. In the first option open to the astronauts, Conrad (who practiced the delicate maneuver on simulators in Houston) will edge the command ship alongside Skylab (see diagram). As he does this, Kerwin or Weitz will lean out of the hatch and attach three newly designed clamps to the ship--two near Skylab's base, one on the telescope mount. The clamps will be used to anchor lines running to the trapezoid-shaped covering. As the lines are tightened, the shade will be pulled into its proper position like the spinnaker on a sailboat (the analogy especially pleases Conrad, who recently acquired a 34-ft. sloop). If this fails, the crew will try again after they have boarded Skylab. One possibility: two of the astronauts will crawl out of a hatch in the space laboratory's airlock module and try to position another Mylar covering over the damaged section with a long extension rod.
The tricky orbital repairs will not be without danger. But NASA technicians and engineers have worked overtime to prepare all the special tools, gears and awnings that will be needed. The Skylab astronauts have flown to Huntsville, where they have run repeated trials of the repair procedures in the simulated zero-G conditions of NASA'S water test tank. Indeed, the intense feeling among NASA'S rank and file reminded Astronaut John Swigert Jr. of the remarkable effort that enabled him and his Apollo 13 crew mates to bring their crippled spacecraft safely back to earth after an explosion. Said Swigert: "I think this incident will show that when the chips are down, we can turn a potential failure into a success. We've done it before. If this had been an unmanned project, it would be lost for sure. This is going to show again what man can do out there to save the mission."
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