Saving Skylab: The launch of the first crew

Fifty years ago, May 25, 1973: The first crew inspects the Skylab space station upon arrival. The Apollo Telescope Mount extends vertically from the body of the station. The gold surface marks the area where the meteoroid shield peeled away. The stuck solar power wing is visible to the bottom right.


After midnight on May 25, 1973, as we sleep ahead of our 9 a.m. launch to rescue Skylab, headlights seek out Pad 39-B where our Apollo ferry and Saturn IB booster are being fueled.  Those headlights belong to vehicles rushing an important cargo to be loaded aboard our Command Module.  After last minute decisions and modifications, sunshades selected by from multiple candidates to save the space station from overheating are finally here.

Barely a week has passed since the 118-ft.-long space station was launched aboard the last Saturn V.  A minute into the flight a micrometeoroid shield peeled away from the belly of the station, unlatched one of two large solar wings, which later blew away.  And the other critical wing was pinned under debris from the shield.  Images from spy satellites and ground-based telescopes fairly well establish the second wing is still there, partially opened.  

Our eyes will be needed to verify the condition of the station and whether we can save it.  We are Pete Conrad, Joe Kerwin, and Paul Weitz, the first Skylab crew (numbered Skylab 2 in NASA’s nomenclature, as the station itself was Skylab 1).

What a dizzying time since launch on May 14 once the seriousness of Skylab’s problems became evident.   At first the lack of power seemed the main problem to overcome, with four “windmill” arrays of the Apollo Telescope Mount, providing the only source of power, less than half of what the two big wings on the sides the Orbital Workshop would haveproduced.  We need the power of the that stuck wing.  

However, by Skylab’s second day, May 15, rising temperatures inside the station took priority, as the missing micrometeoroid shield also served as a sunshield.  Controllers began experimenting with pointing the station in various attitudes to the sun to reduce heating.  That had to be balanced against the need to point the windmill arrays at the sun.  It took time to work out the proper balance, tipping the nose of the station towards earth so that the telescope mount, riding at 90 degrees from the body of the station, would provide shade.  They’d hold that for an orbit, then on the next orbit, tilt the station back so the arrays could provide power and charge batteries.  And then repeating the cycle.  By the next day, May 17, the optimum angles had been discovered, enough to stabilize temperatures inside the main workshop at about 130 degrees F.

Optimism rose that day concerning the chances of saving the station.  Plans were coming together on several designs of sunshields.  The Johnson Space Center in Houston suggested using a lightweight aluminized mylar covered with a nylon layer for the sunshade.   The Marshall Space Flight Center in Huntsville, Alabama, took the lead in developing ideas for deploying the sunshade.  The focus narrowed to three methods.  One would have the crew deploy a sunshade from the open hatch of the free-flying Apollo, attaching it at the base and then tying it down at the front at the struts to the telescope mount.  Another idea involved a spacewalk from the station, extending the shield along booms.  A third idea involved use of a small scientific airlock in the side of the workshop facing the sun.  With an square opening of 10 in. on each side, it was designed to expose experiments outside the station.  Perhaps a umbrella-like shield could be extended through this airlock and opened.  At first, this is considered a back-up device to carry.

With satellite photos indicating that a single strap may be restraining the stuck solar wing, plans to free it also advanced on May 17.  NASA contacted a company specializing in long-handled cutters and tools used by utility line workers, A.B. Chance Company of Centralia, Missouri, who rushed various tools to Marshall where, with the advise of backup Skylab commander, Rusty Schweickart, two are selected for modification, a cable cutter and a two-pronged pry tool.

On this date, launch was reset for May 25, with a crush of work to be done to fabricate the shields and practice their deployment.  All three would be carried.  The parasol extended through the airlock jumped from backup to the prime candidate on May 19, as it would be the easiest to deploy.  If, that is, debris was not blocking the scientific airlock.  The parasol shield would be fitted into a standard experiment canister designed for use with the airlock.  It measured 8.5 by 8.5 by 53 in.  The same aluminum rods designed for use with experiments would be used to extend the folded parasol.  Once the mast was extended from the airlock, four telescoping deployment rods would open the shield measuring 22 by 24 ft.  The mast would then be retracted against the side of the station.

Starting on May 19, we practice freeing the solar wing underwater in the “WETF,” Weightless Environment Training Facility, on a “junk pile” of simulated debris pinning the wing down.  Launch is just six days away.  

Other concerns continue to arise and be addressed.  The inner walls of the workshop are insulated with a layer of polyurethane foam.  The extreme heat could cause the insulation to outgas toxic gasses.  Tests show that the large volume of the workshop should dilute any toxins, but to make sure, the interior atmosphere, composed of nitrogen for launch, is purged and replaced several times.  Gas testing equipment and masks are added to the Apollo manifest.  

The heat could spoil food and film.  Test show that most should withstand the temperatures.  By May 21 plans and procedures had firmed up.  The crew has a voice, and we give our final approval the next day, only three days until launch. 

All in all, ours will be the heaviest command module, carrying 180 lbs. of extra equipment.  And our Service Module also will carry extra 220 lbs. of oxygen and hydrogen reactants for its two electricity-producing fuel cells.  We will supplement the windmill solar arrays with power from the fuel cells.  This should provide enough power for us to conduct a wide load of science activities for at least a couple weeks or more, just in case we can’t salvage the solar power wing.  In power-down mode, we’d stretch our flight to the intended 28 days, a new duration record.

On May 23, the countdown resumes.


Launch day

Stowage aboard the Apollo is complete at 4:20 a.m. on launch morning, the extra equipment strapped under our seats.  We, the crew, have been awake about 45 min. by then, cycling through the pre-launch rituals of breakfast and suiting up.  And the walkout to the van that carries us to the pad and the sight of the 224-ft.-tall Saturn IB/Apollo, sitting on a latticework pedestal, the “milk stool,” so that it matches the swing arms designed for a much taller Saturn V.  This is the first launch of a Saturn IB since Apollo 7 in October 1968.  The original Saturn IB pads have long been decommissioned.  The milk stool allows us to launch from Pad 39-B, its first use since Apollo 10 in 1969.

By 7 a.m., the hatch is closed.  All is on schedule for a 9 a.m. launch.  On time the eight H-1 engines ignite.  Launch commit and liftoff.  Our mission commander, Pete Conrad calls, “Houston, Skylab 2.  We fix anything.  And we’ve got a pitch and roll program.”  

The first stage ride is smooth, much smoother than an Saturn V.  The stage fires for about 2.5 min.  Staging, and we’re off on the familiar Saturn S-IVB upper stage used by both the Saturn IB and the Saturn V.  “Nice staging,” Conrad calls.  We need to burn this stage for about 6.5 min. to place us in orbit.  We’re go.  The numbers tick by perfectly as we arrow through our keyhole to the sky.

And shutdown, 9 min. 46 sec. since launch.  We’ve entered an orbit of 221.8 by 96.9 mi.

“Skylab, Houston.  We confirm that you’re in a nominal orbit, ” calls Capcom Dick Truly.   The chase is on — Skylab is 898 mi. ahead of us and in a higher orbit, a circular one of 270 mi.  We will make four rendezvous maneuvers through the next five hours to draw us to the station.

Step by step we close in.  Over U.S. on start of fifth orbit, we begin prep for Terminal Phase Initiation burn, placing us an intercept course.  “Houston, we had a good TPI burn,” we report through the Canarvon, Australia, station.  When we come into daylight, we see it.  Conrad calls “Tallyho the Skylab.”

As we draw near, the station’s huge size overwhelms us. And we clearly see it’s condition.  “Houston, I can already see the partially deployed solar panel.” Pete radios.  Then moments later, “The meteoroid shield area is solid gold.” 

“Whooie,” Conrad calls as pulls within 5 ft. of station — we’re inspecting the debris near stuck array.  It’s 4:30 p.m. EDT, 7.5 hrs. since launch.  

“As you suspected, solar wing 2 is gone completely off the bird.  Solar wing 1 is, in fact, partially deployed.  There is a bulge of meteorite shield underneath in the middle . . .  I think that we can take care of that with the SEVA [stand-up EVA].  It looks, at first inspection, like we ought to be able to get it out.  The gold foil has turned considerably black in the sun.”

We move around cluster inspecting it.  The wing is jammed about 15 degrees out.  We believe that the wing’s boom is hung up by a single wedge-shaped strap from the edge of the missing meteoroid shield.  Over the U.S., we transmit 15 min. of TV showing the station’s condition.

And importantly, no debris is blocking the scientific airlock.  We should be able to deploy the parasol.  

We move out of tracking range over the U.S. at start of 6th orbit, 8 hr. 14 min. since launch (5:14 p.m. EST).  Fifty-five minutes after rendezvousing, we dock with the axial port at the nose of the station.  That’s how fast events are moving. We only make a soft dock, held by the three capture latches at the nose of the docking mechanism, as we’ll be undocking soon.  And take a break for a meal.  Pete  comments, “Boy, I’ve had some big things in my nose in space before, but this by far the biggest. It sure beats the Agena or the LM.”  The Agena was the target stage Pete docked with on his second flight, Gemini 11.

“We’re sitting up here discussing our plan of attack.”  After undocking, we’ll move near the stuck wing as Paul Weitz conducts a “SEVA” (stand-up EVA) leaning out of the hatch.  We’ll hold his feet steady as his reaches out with the two tools on 10-ft poles. 

At 6:34 p.m., as we come into contact with Goldstone, preparations are underway for the SEVA, and 25 min. later, a tracking ship relays a message from Mission Control and capcom Dick Truly:  “Pete, we’ve been talking about a lot of things here on the ground, but I guess about the only thing we feel like passing up is the fact that we probably think if the piece of metals that’s bent over the wing is indeed a little piece of angle iron, that you probably cannot cut it, and so if you want to get it out of the way you’ll probably have to be it, but it’ll be strictly your call when you guys get out there there.”

Our best bet is to use the to the pry bar and pull the wing free  We’re set.  Truly calls, “You’re cleared for local flight.  Have fun and fly safe.”

We will be out of comm range much of the time, over the Pacific.  Pete brings us along side the wing.  Paul leans out.  Tug  and Tugs.  He tugs so hard he’s breathing heavy.  Each tug upsets the stability of the two vehicles.  Pete wrestles the Apollo back into position.  We try and try to pry that wing loose, upsetting the apple cart.    

Skylab begins to oscillate, it’s cold-gas nitrogen jets firing, eating up fuel  (with all maneuvering since launch, only 54.5 percent of Skylab’s nitrogen fuel remains).  It’s so frustrating — it’s a little strap, about an inch long and a half inch wide.  We just can’t budge it.  It has a line of bolts along it, and they’re like teeth biting into the wing’s deployment boom. 

“I’ve got a cutoff point in 12 min.” — when we pass into darkness.  

Coming back in comm range 8:10 p.m EDT, we tell Houston. “We couldn’t get it out right now.  We’re going to have to give it up.  But I really feel bad because there’s just one one tiny little half-inch strip.”  

It’s been an effort of 37 min.  “We ain’t going to get it with the tools we have.”  Jesus, it’s awkward working with those long poles.  Twice Conrad gets thunked on the helmet as we pull them back inside.  He has a few choice expletives about that.  Indeed, we all have a few expletives about that damn stubborn little strap.

We circle around to dock to the nose of the station.  Bring her in slowly . . .  And those three capture latches in the tip of the probe slide into the funnel-like drogue on the station . . .  And fail to latch.  We pull back and try again, and again, “no joy,” as we say.

When in contact with Vanguard tracking ship, Pete reports.  “I’ve made two attempts to get a soft dock, and now I can’t get one, and we are just about to start through the emergency procedures and standing by for any of your suggestions.”   

We soon will be out of com for another one-hour period.  Try once more, Houston says, then go through procedures for trouble-shooting the probe.  We drive in again.  At 9:43 p.m. EDT, over Hawaii, Houston calls, “Pete’s what your status?”

No joy.  They suggest one final option before backing away from Skylab, giving up for the night.  Depressurized the CM, take out the forward hatch, remove the docking probe, electrically bypass the circuit to retract the extended probe.  Attach a “jumper cable,” onboard for just such a case, to directly power the 12 “hard-dock” latches at the rim of the docking tunnel.  Then drive forward directly to hard dock, just like Apollo 14 had to do.  

We wait for darkness when docking aids would be more visible in our lights.  Pete pours on the coals and drives us hard in.  It’s 11:30 p.m.  . . . And at 11:52 p.m. EDT, we come in range of the Vanguard tracking ship.  Pete gives the word:  ” Yea! We got a hard dock out of it!”

We will sleep in the Apollo’s Command Module overnight.  Pete tells Houston, “We’ve had our problems, you’ve had your problems.  So we’ll get this thing set up and hit the pad.”   It’s been a long 22-hr. day.


The second day

It’s flight day 2, May 26, 1973.  Our day begins at 10:05 a.m. EDT.  Our focus shifts to entering the station and deploying the parasol shield.   We spend early morning spent troubleshooting and at 12:30 p.m. EDT inserted special tube in the Skylab hatch to test the air in the Multiple Docking Adapter (MDA), the first of two smaller cylindrical modules before reaching the large workshop itself.  It detects no toxic gasses, and 5 min. later, we open the hatch.  In MDA, it’s much cooler than it will be in large workshop, whose interior temperature is about 130 degrees F.  Over Hawaii, we call, “OK, Houston, we’re in the MDA, and we’re pretty busy . . .”  

Shortly after 2 p.m. EDT, we move into the OWS, the Orbital Workshop, wearing gas masks, a quick in-and-out inspection.  A half hour later we report to capcom Hank Hartsfield, “OK, on our very quick inspection, the OWS appears to be in good shape.  It feels a bit warm, as you might expect.  From the 3 – or – 5 min. I spent in there, I would say, subjectively, it feels like . . . in the desert.  Hank, I could fee the heat radiating from all around me, but in the short time I was in there, I never felt uncomfortable.  I had soft shoes and gloves on, and nothing I touched even felt hot to me.”

We wait for more air tests.  Finally word:  “You’re go for entering the OWS.”    We move into the workshop at about 5 p.m. EDT.   It smells like hot metal in there.  We’re able to work up to five hours at a time, taking short breaks in the cooler MDA module.  “Feels a little bit warm, as you might expect, like 90 or 100 degrees in the desert.  It’ a dry heat.”

Pete tells Houston, “Mobility around here is super.  It turned out to work better than we even hoped for.  Nobody has any problem with any feeling of motion sickness or anything, so we’re all squared away on that.  Everything that we’ve been supposed to unfold or move has been easier than we could have hoped.”  We begin the long process of preparing the for the parasol deployment.

At 7:30 p.m. EDT, we report, “We are progressing slow but sure, and everything is working.”  It’s another long day, but we’re nearly ready.  Joe Kerwin moves into Apollo and sets up TV in CM hoping to view deployment of the rods.

And we wait for sunrise at 8:26 p.m. EDT over Sri Lanka, out of comm range . . .  

From the airlock controls, we extend the mast, rod by rod, five rods of aluminum tubing, each 4-ft long.   When it reaches 16 ft., we release the four telescoping legs of the “umbrella.”  As they swing open, we extend the mast to 21 ft., so that the end of the telescoping rods will clear the hull.  In a few minutes, it’s deployed, but looks wrinkled, misshaped.  Joe, watching from the CM, sees the rods “come up smartly, but the back legs came up a little more slowly.”  We’re disappointed.  As planned, we wait word with Houston before retracting the sunshield against the hull.

When come in contact with Hawaii 9:03 p.m. EDT, Pete reports, “We had a clean deployment as far as the rods, clearing and everything, but it’s not laid out the wait it’s supposed to be.”

“It’s more fulling deployed in front, but there are two folds, three folds, emanating fro the center.  So in effect we have a trapezoid which has the smallest dimension toward the base of the vehicle.”  It’s about 12 to 14 ft. at base and 18 to 20 ft. at top.  

“We’ve oscillated the rods in and out a couple strokes rapidly . . .  It’s more fully deployed in the front across the upper skirt.”  

After discussion on the ground, engineers believe the wrinkles should flatten out in sun.  Capcom Hank Hartsfield says, “We think we have almost a full deployment, and pulling it in will do the rest for us.” 

At about 10 p.m. EDT, we retract the mast.  We make adjustments to the shields alignment and finish up.  And temperatures begin to fall.  Houston places Skylab back in “solar inertial” attitude where the windmill solar arrays will catch the sun.

Temperatures inside the workshop slowly drop toward 90 degrees F.  We’ll sleep in the docking adapter for a few nights, where it is cooler.  And begin our scientific mission.  As for the stuck solar wing, we now have the time to devise a new plan to release it.

Capcom Hank Hartsfield tells us, “I’d just like to say that you guys did a tremendous job.  You’ve got everybody down here smiling now that you’ve got that parasol out.”   

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