Skylab's Final Design
NASA puts it all together
Exploring the intersection of spaceflight history, pop culture, and art.
This edition of Creating Space is the fourth in a series of posts that commemorate the fiftieth anniversaries of the Skylab missions with a continuation of the discussion about the space station’s early development. This time, I talk about the transition from a “wet” workshop to a “dry” concept, the decision to use a Saturn V booster, and I describe the components which made up the final Skylab Orbital Workshop configuration.
Skylab Dry Workshop
In the past several posts, I have been taking readers through the early development of the Skylab workshop and the rockets that would boost it into Earth orbit. This post describes the transition to a “dry” workshop and the decision to use a Saturn V as the launch vehicle.
If you missed the previous Skylab posts, you can find them here:
We’re Gonna Need a Bigger Booster
Up until the beginning of 1969, NASA mission designers had been planning to launch a series of Saturn IB rockets to boost Skylab’s components into orbit. Several launches would be needed to accommodate the ever-growing collection of scientific payloads that were being considered for what had become known as the “cluster” configuration.
Still on the drawing boards at that time was the so-called “wet workshop” that used, in addition to the Saturn IB first stage, the propulsive force of a fueled S-IVB second stage to get into space. After any unused fuel was vented, astronauts would attempt to insert equipment into the spent stage by way of a large forward hatch – a scheme that would prove troublesome during neutral buoyancy tank tests.
As the number of mission objectives increased over time, and the modules meant to perform the science inevitably grew in size and weight, engineers realized they were nearing the limited lifting capabilities of the Saturn IB for some of the planned launches.1 In the early months of 1969, just four years before Skylab would eventually be launched, NASA began to seriously reconsider its choice of rocket for Skylab.2
Stepping up from the Saturn IB to the enormous capability of the Saturn V would permit the entire workshop to be placed into the desired orbit in a single launch, including its cluster of modules. The Saturn V would also provide enough lifting power to enable fully outfitting the S-IVB (normally used as its third stage) with the necessary interior workspace, crew quarters, and scientific equipment while still on the ground. This was a very attractive option given the difficulties test crew had in opening the large forward hatch at the top of the S-IVB’s fuel tank during underwater training tests.
Brother, Can You Spare a Moon Rocket?
Although mission studies using a Saturn V booster to lift Skylab had been going on for some months, the Apollo lunar program had a limited number of the giant rockets with which to execute all of the planned flights to the Moon. As originally conceived, Apollo would include ten manned lunar landings. Added to those would be unmanned test vehicles as well as flights into orbit around the Moon. All the long distance flights would be launched with Saturn V rockets. As of 1966, NASA’s plan was to launch fifteen Apollo Saturn V vehicles by the end of 1970.3
The wildly successful circumlunar mission of Apollo 8 in 1968 began to give NASA management hope that a Saturn V could be spared from the Apollo program.4 In July of 1969, NASA Administrator Thomas Paine approved the shift from a "wet" to a "dry'' workshop.5
Then, at the beginning of 1970, after Apollo 11’s historic lunar landing in the Sea of Tranquility the prior year, NASA announced the cancellation of Apollo 20.6 This would be followed by two more landing missions being cancelled. It seemed that Skylab had found its big booster.
Putting It All Together
Skylab’s pre-stuffed S-IVB stage would not need to be fueled, as such it was known as the “dry” workshop. It would be comprised of five major assemblies – the main workshop volume, an airlock for EVAs, a docking adapter, a solar observatory known as the Apollo Telescope Mount (ATM), and the Apollo spacecraft used to ferry the crew to and from the orbiting workshop.7
In the launch configuration, the workshop’s components were lined up along the rocket’s vertical axis and covered with an aerodynamic shroud. Once in orbit, the ATM would fold out ninety degrees to the side and automatically lock into place.
Two sets of solar panels would provide the power to all of the workshop’s systems and science equipment. The first set of panels would deploy out from the sides of the main workshop S-IVB stage, resembling outstretched wings. Due to a damaging mishap during the launch, one of the side solar arrays was torn off and the other did not properly deploy.
The second set of panels, and perhaps most distinctively recognizable feature of the cluster, was made up of four long, slender, solar arrays that stretched outward in a diagonal ‘X’ configuration, giving the whole assembly the appearance of a windmill.
The main workshop, built from the 22 foot (6.7 m) diameter Saturn S-IVB stage, housed the crew quarters and an experiment area. This was where the astronauts lived and worked.
In addition to the aforementioned solar panels, the exterior of the workshop was surrounded by micrometeoroid shields that would extend out several inches from the cylindrical hull of the workshop and provide protection from micrometeoroid strikes as well as thermal protection from the Sun’s rays. It was the premature deployment of one of these shields that led to the damage to the main solar panel arrays, as well as causing a major overheating problem. The daring and innovative collective efforts by ground personnel and flight crews that ultimately salvaged the workshop turned out to be one of the major achievements of the program, albeit completely unplanned. The reader is encouraged to seek out one of the many accounts of how Skylab was saved, since it is beyond the scope of this post.
The interior space of the workshop was divided into two main sections separated by a metal grid floor. The lower section contained the astronauts’ sleep compartments, the wardroom and galley, the waste management compartment, and an area set aside for specific biomedical experiments.
The larger upper section contained stowage lockers, water supply, environmental control system, a food freezer, film vaults, as well as an Earth observation window, a scientific airlock, and the hatch leading to the airlock.
The large upper volume found use as both an area for testing prototype astronaut maneuvering units such as that eventually used during the Shuttle program, as well as a recreational space the astronauts found irresistible for experimenting (a.k.a. playing) in the zero-G environment.
At the extreme aft end was an empty tank used for waste. This tank would have been filled with liquid oxygen in a standard propulsively-used S-IVB stage.
Forward of the workshop cylinder was the airlock module. The EVA hatch (procured from McDonnell Douglas’ Gemini program) was used to access the end of the ATM for film retrieval. Distributed within a protective ring at the base of the airlock were tanks containing breathing oxygen and nitrogen.
Ahead of the airlock was the multiple docking adapter (MDA) which had two docking ports – one for crews visiting the station in the CSM and a second port reserved for emergencies. The MDA also served as the control center for solar observations, Earth resources observations, and materials processing experiments.8
The Apollo Telescope Mount (ATM) contained a ten foot (3 m) long cylindrical canister which, in turn, housed a multitude of solar observing instruments and film cameras. Each instrument was covered by protective aperture doors which could be opened and closed as needed. Surrounding the circular end of the canister was a solar shade.
The ATM assembly was supported by a truss which allowed it to be deployed out to the side of the docking adapter. Extending outward were four long rectangular solar arrays providing power to the instruments. Hand rails and foot restraints were distributed in such a way as to assist astronauts in retrieving film.
Three control moment gyroscopes positioned around the base of the truss, oriented in three orthogonal axes, were used for attitude pointing and control of the workshop.9
Absent was the LEM ascent stage that was included in earlier conceptual design phases.
It is interesting to note the origins of the Skylab telescope mount. In the early 1960s, when the Apollo program plans included much more than lunar landings, NASA conducted so-called Apollo Extensions Support Studies that identified possible projects which could use launch vehicles and spacecraft components developed for Apollo.10 One of the ideas was to use the Apollo CSM to carry an assembly of small solar telescopes into orbit. Seen here is an artist’s depiction of that concept, looking as if it came straight out of a 1950s sci-fi movie.
Wait! There’s more!
While researching this story, I came across an excellent video overview of Skylab. Compiled and remastered historical archive space exploration footage by Retro Space HD. (Facebook, Instagram, Patreon, Twitter, YouTube)
Art News
My space-inspired artwork, Moonlight Dreams, continues its run as part of the Art+Flight celebration at the Museum of Flight in Seattle, Washington. The celebration runs through January 7, 2024.
If you haven’t yet read about the exhibition and my artwork that is displayed, refer back to the following two posts to get filled in on the facts.
Art News from Moonlight Dreams post, June 4, 2023
Art News from The collectSPACE Insignia post, July 8, 2023
Stop by if you are in the Seattle area and check out the clear brilliant colors of my metal prints first hand. Prints are available for purchase in the museum store, and you can always find Moonlight Dreams and more of my artwork for sale at my online shop.
Art+Flight is free with Museum admission.
Open Daily, 10:00 AM to 5:00 PM
Admission FREE 5:00 PM to 9:00 PM the first Thursday of every month.
The Museum of Flight is located at 9404 East Marginal Way South, Seattle, WA 98108.
Recommendation of the Month
As a reader of Creating Space, I know you enjoy a good space NERDSletter. From time to time, I will share other space-related blogs that I find interesting.
Jatan Mehta describes his newsletter as one “exploring space and our Moon, for science and a better future for humanity.” His weekly Moon Monday posts are a digest of current and upcoming lunar missions. There’s a lot going on right now, and reading Jatan’s Space is a great way to keep up to date.
I’m Dave Ginsberg, the artist behind Pixel Planet Pictures and writer of Creating Space.
I am an artist and a creative engineer with a love for teaching and passions for spaceflight, astronomy, and science. My space-inspired art portfolio can be found at pixel-planet-pictures.com. You can also follow me on Instagram (pixelplanetpics).
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If you’ve been reading down to the bottom of each post, you know that I have a website called Pixel Planet Pictures where I display and sell my space-inspired artwork. I invite you to visit my site.
If you are considering adding some of my artwork to your collection, I have good news for you.
As a special thank-you for reading Creating Space, I am offering a discount on my artwork.
Simply use code CREATINGSPACE15% for 15% off your entire order from the Pixel Planet Pictures shop.
All images and text copyright © Dave Ginsberg, unless otherwise noted. All rights reserved.
SP-4208 Living and Working in Space: A History of Skylab, W. David Compton, Charles D. Bensen, NASA, 1983
SP-4208 Living and Working in Space: A History of Skylab, W. David Compton, Charles D. Bensen, NASA, 1983
Saturn Illustrated Chronology - Part 7, David S. Akens, NASA Historical Office
SP-4208 Living and Working in Space: A History of Skylab - Chapter 5, W. David Compton, Charles D. Bensen, NASA, 1983
Skylab– A Chronology, Roland W. Newkirk and Ivan D. Ertel with Courtney G. Brooks SP-4011, 1977
Canceled Apollo missions, https://en.wikipedia.org/w/index.php?title=Canceled_Apollo_missions&oldid=1175749666 (last visited Oct. 13, 2023).
SP-400 Skylab, Our First Space Station, Edited by Leland F. Belew, NASA, George C. Marshall Space Flight Center, 1977
Multiple Docking Adapter, Skylab, Smithsonian National Air and Space Museum
NASA TH D-6068, Skylab Attitude and pointing Control System, W. B. Chubb and S. M. Selzer, George C. Marshall Space Flight Center, NASA, February 1971
EP-107 Skylab: A Guidebook - Chapter 2, Leland F. Belew, Ernst Stuhlinger, NASA, George C. Marshall Space Flight Center, 1973
Another great in depth article, thanks Dave!