The Skylab Program: Pioneering NASA’s Human Spaceflight

Artist illustration of Skylab
Source: NASA

The Skylab Program, announced by NASA 53 years ago, marked a significant chapter in the history of human spaceflight. It was America’s first experimental space station, designed for humans to live and work in for extended periods. The program’s ambitious scope aimed to expand our understanding of life in space; and ultimately ended up establishing the foundation for future international space stations.

The Birth of Skylab

The Skylab Program was born from the Apollo Applications Program (AAP), which was intended to find practical applications for the hardware developed for the Apollo moon missions. Recognizing the potential to utilize the Saturn rockets and Apollo spacecraft for more than just lunar landings, NASA proposed the idea of a space station. This would allow scientists to study the effects of long-term space travel on the human body, an area of research that was largely unexplored at the time.

The Skylab program was officially announced by NASA on February 14, 1970.

Skylab Repair Work

Last picture of Skylab as Skylab 4 crew returns home.

The launch of Skylab on May 14, 1973, didn’t go as smoothly as planned. During the launch, the station’s micrometeoroid shield, which also served as a sunshade, was torn off. This unfortunate event led to a loss of one of the station’s main solar panels and exposed the remaining workshop area to intense solar heating. The resulting high temperatures inside the station made it uninhabitable and caused a critical situation due to insufficient power generation.

In response to the crisis, NASA had to postpone the launch of the first crewed mission, Skylab 2, from May 15 to May 25, 1973. This delay was necessary to provide the crew, consisting of astronauts Charles “Pete” Conrad, Joseph Kerwin, and Paul Weitz, with the necessary training for the unexpected and challenging task of repairing Skylab. The repair process involved two major tasks: deploying a sunshade to cool the station and releasing the remaining jammed solar panel to restore power.

The astronauts faced a challenging and hazardous task. They had to work in the vacuum of space, wearing bulky spacesuits, and use tools designed for zero gravity. During their first extravehicular activity (EVA), or spacewalk, the crew attempted to free the jammed solar panel but were unsuccessful.

The crew then focused on reducing the station’s interior temperature. They successfully deployed a parasol sunshade through a small scientific airlock. This sunshade was designed to replace the lost micrometeoroid shield and was effective in lowering the temperature inside the Skylab to acceptable levels.

On their eleventh day in space, the crew made a second EVA attempt to free the jammed solar panel. This time, they were successful, using a combination of tools and their own strength to release the panel. With the solar panel deployed, the power supply was significantly improved, and the astronauts could fully utilize Skylab’s facilities for their scientific experiments.

This repair work was a significant milestone in the history of space exploration. It was one of the first instances where major unplanned repair work was carried out in space, demonstrating the feasibility of in-space repairs, a vital capability for the long-term human presence in space. The successful repair of Skylab by the astronauts of Skylab 2 mission is an enduring testament to human ingenuity and adaptability in the face of unexpected challenges.

Skylab Missions

Despite the initial hurdles, three successful manned missions to Skylab were carried out between 1973 and 1974, known as Skylab 2, Skylab 3, and Skylab 4. The missions lasted approximately 28, 59, and 84 days, respectively.

Each crew consisted of three astronauts. Skylab 2’s crew included Charles “Pete” Conrad, Joseph Kerwin, and Paul Weitz. Skylab 3 was manned by Alan Bean, Jack Lousma, and Owen Garriott, while Skylab 4’s crew consisted of Gerald Carr, William Pogue, and Edward Gibson.

The Skylab astronauts conducted numerous scientific experiments, particularly focusing on the physical effects of long-term weightlessness. They also carried out solar observations and Earth resources experiments, providing valuable data that influenced the design and operation of future space stations.

Life on Skylab

Inside, Skylab was spacious compared to any spacecraft of its time. It had a wardroom with a table where astronauts could eat meals and hold meetings, a window for Earth viewing, and even a small shower. The crews had private sleeping quarters, a luxury not afforded on the Apollo missions.

Astronauts’ daily routines included exercise, work, meals, leisure time, and sleep. Exercise was especially important due to the effects of microgravity on muscle mass and bone density. Astronauts spent about two hours each day on exercise, using specially designed equipment.

The program also served as a social experiment, observing how crews coped with the psychological challenges of long-duration spaceflight. The Skylab 4 crew experienced some of these challenges, leading to a temporary slowdown of their work schedule, an episode sometimes referred to as the “Skylab mutiny”.

A Typical Workday on Skylab

Life on Skylab was a mix of work, exercise, leisure, and sleep, all structured around a schedule communicated by mission control. This structure was essential in helping the crew members maintain their mental and physical well-being during their extended stays in the microgravity environment of space. Here’s a glimpse into what a typical day aboard Skylab might look like:


The crew’s day would begin with a wake-up call from mission control. After a brief period of time to acclimate themselves from sleep, the astronauts would start their day with personal hygiene activities, using specially designed equipment for brushing teeth and washing themselves in zero gravity.

Next was breakfast, with meals often consisting of thermostabilized, dehydrated, or freeze-dried foods that could be rehydrated with a water gun. The astronauts had a variety of foods to choose from, including bacon squares, scrambled eggs, and even grape drink.

Following breakfast, the crew would have a daily planning conference with mission control to discuss the day’s schedule, any changes, and to address questions or concerns.


The primary workday began after this planning conference. Work activities varied day by day but often included scientific experiments, spacecraft maintenance, system checks, and communication with mission control. This could involve anything from medical experiments investigating the effects of microgravity on the human body, to solar observations using Skylab’s solar telescopes, to deploying and retrieving scientific instruments outside the station during spacewalks.


Physical exercise was a crucial part of the daily routine. NASA had learned from earlier missions that physical exercise was vital in countering the muscle atrophy and bone density loss associated with long-duration spaceflight. The crew spent about two hours each day exercising, using a bicycle ergometer and a device for isometric exercises.


Following the workday, the crew would have a period of free time. They could use this time to look out the window and photograph Earth, catch up on personal tasks, or simply relax. Dinner was similar to breakfast, with a variety of rehydratable foods available.

Before bedtime, the crew had another planning conference with mission control to review the day’s work and prepare for the next day. After this, they would have a bit more free time to relax or to finish up any remaining tasks.


Sleeping in space presented its own challenges, as the microgravity environment meant the astronauts would float around if not restrained. Each crew member had a small sleep compartment with straps to prevent them from floating around. The sleep period lasted about 8 hours.

Overall, while a day aboard Skylab was tightly scheduled and filled with work, NASA took care to ensure that the astronauts also had time for rest, relaxation, and exercise. This balance was key to helping them stay healthy and productive during their extended stays in space.

The Skylab 4 “Mutiny”

One of the most notable events in the Skylab program was the so-called “mutiny” that occurred during the Skylab 4 mission, the third and final crewed mission to the space station. This incident, while not a mutiny in the traditional sense, was a significant event in the history of human spaceflight and continues to inform how astronauts are trained and managed today.

Skylab 4 was the longest of the Skylab missions, lasting 84 days. The crew, consisting of Gerald Carr, Edward Gibson, and William Pogue, were all rookie astronauts. Their mission was packed with tasks, from scientific experiments to space station maintenance.

The trouble began shortly after the mission started. Pogue became space sick, an occurrence not unusual for astronauts but one that wasn’t immediately reported to ground control. This led to a backlog in their heavy work schedule. The crew also felt that they were being micromanaged by ground control and that their work schedule didn’t allow for sufficient rest and relaxation.

By mid-December, about six weeks into the mission, tensions came to a head. The crew requested a day off, which mission control denied. In response, the crew took a day off anyway, turning off the communications radio for a period of time. They spent the day relaxing and looking at the Earth.

This act of defiance was unprecedented. When communication was reestablished, there was a series of discussions between the astronauts and ground control about the scheduling issues. Ground control acknowledged the overpacked schedule and agreed to more flexible planning. They also agreed to allow the crew more time for rest and relaxation.

The event became known as the “Skylab mutiny”, though this term is arguably a misnomer. The crew didn’t attempt to seize control of the spacecraft, and they were never in any danger. Instead, it was a labor strike of sorts, with the crew advocating for their right to rest and manage their own time.

The “mutiny” had significant implications for future space missions. It underscored the importance of considering crew welfare and the psychological impacts of long-duration spaceflight. It led NASA to change its approach to mission planning, including more input from astronauts into their schedules and allowing more time for relaxation and exercise. These lessons continue to be applied today, particularly on the International Space Station.

The Mold Problem on Skylab

While Skylab is remembered for its many successes, it also faced some challenges, including an issue with mold. The problem arose during the second crewed mission, Skylab 3, and persisted throughout Skylab 4. It was an unexpected issue that provided important lessons for future long-duration space missions.

After several weeks in the moist and warm environment of the Skylab, a mold began to grow. The mold, a species of Penicillium, was found on the on-board exercise equipment, the crew’s sleeping quarters, and some food storage areas. It was not harmful to the astronauts, but it was a nuisance and highlighted the challenges of maintaining a clean environment on long-duration space missions.

The crew had to spend considerable time cleaning the moldy areas. They used wet wipes soaked in a disinfectant solution to clean the surfaces, a time-consuming task that diverted them from their scientific work. The mold returned frequently, showing how stubborn such a problem could be in the closed environment of a space station.

The mold issue on Skylab provided important lessons for NASA about the need for effective countermeasures against microbial growth in spacecraft, especially for long-duration missions. It led to changes in the design and materials used in spacecraft, as well as the development of improved sanitation practices.

For instance, more resistant materials were chosen for interior surfaces, and stricter protocols were put in place for cleaning and maintenance. Also, the food storage was improved to prevent contamination. The experience gained from the Skylab mold problem has helped keep subsequent space stations, like the International Space Station, cleaner and healthier for their crews.

The Skylab mold problem is a reminder that space exploration often brings unexpected challenges. It is also a testament to the adaptability of astronauts and their support teams on Earth, who are always ready to address and learn from these challenges.

NASA’s Skylab Rescue Plans

Given the extended duration of the Skylab missions, NASA developed contingency plans to ensure the safety of the astronauts in the event of an emergency or a failure of the Apollo spacecraft that could prevent their safe return to Earth. This was the first time NASA had put such a rescue plan in place, and it involved having a second Apollo command and service module (CSM) ready for launch on short notice.

The rescue vehicle, an Apollo command module with modification, was designed to carry a two-person rescue crew in addition to being able to bring home the three-person crew stranded in Skylab. The rescue vehicle was stripped of some of its scientific equipment to make room for the additional astronaut during the return journey.

If a rescue mission was required, the two-person crew would launch in the modified Apollo CSM and dock with Skylab. The rescue crew would then transfer the stranded astronauts to the rescue vehicle, and they would all return to Earth together.

Fortunately, NASA never needed to implement these plans as all the Skylab missions returned safely. However, the planning and readiness demonstrated by NASA to have a rescue mission prepared was a testament to the agency’s commitment to astronaut safety. It also provided valuable experience in planning and preparing for potential emergencies in human spaceflight, experience that has informed safety protocols for subsequent missions and programs.

SkyLab’s Premature Reentry

The reentry of Skylab into Earth’s atmosphere was a significant event. NASA had originally planned to use the Space Shuttle, then in development, to reboost Skylab and extend its operational life. However, delays in the Shuttle program and higher-than-expected solar activity (which increased atmospheric drag) led to Skylab’s premature reentry in 1979. The reentry was partially controlled; NASA guided the station to a footprint over the Indian Ocean, but some debris fell over Western Australia. The event led to international discussions about space debris and reentry hazards, and it underscored the need for better end-of-life planning for spacecraft.

Artificial Gravity Experiments

One of the planned Skylab missions, which was never realized, was to have involved an experiment in artificial gravity. The plan was to have the Apollo command/service module remain attached to Skylab and use the rocket’s engines to spin the combined spacecraft, creating centrifugal force that would mimic gravity. This mission was cancelled due to budget cuts and the damage to Skylab during its launch.

Legacy of the Skylab Program

While Skylab’s operational life was relatively short, the lessons learned from its missions were invaluable and continue to shape human spaceflight.

Scientific Achievements

The Skylab Program offered a wealth of new scientific and medical data about the effects of long-duration spaceflight on the human body. This was pivotal for the development of the Space Shuttle program and the International Space Station (ISS).

The Skylab missions provided researchers with an unprecedented volume of data on various aspects of space life. Experiments conducted during the Skylab missions explored life sciences, earth resources, solar observations, and more. These experiments provided insights into how the human body adapts to the weightless environment, how to manage resources, and how to conduct complex scientific research in space.

The missions provided the first opportunity to observe the sun’s corona and chromosphere without atmospheric interference. The Apollo Telescope Mount (ATM), an array of solar telescopes, provided detailed images of the Sun’s surface and solar flares. This solar observatory was a critical addition to Skylab, contributing immensely to solar physics.

Skylab also facilitated the development of innovative space technologies and systems. The station was equipped with state-of-the-art systems for environmental control, waste management, and water recycling. These technologies were later refined for use on the Space Shuttle and International Space Station.

The experiments on material sciences in the microgravity environment also yielded interesting results, leading to advancements in various scientific and industrial applications. The mission also contributed to the development of telemedicine and remote health monitoring technologies, as maintaining the astronauts’ health was of paramount importance during these extended stays in space.

Overall, the Skylab Program was a groundbreaking endeavor that advanced our capabilities and knowledge of living and working in space. It marked a critical step in the evolution of space stations, from the single-use capsules of the Apollo era to the semi-permanent structures like the International Space Station we know today. Despite the challenges and hardships, the program’s success reinforced the notion that humans could survive in space, paving the way for future exploration and our continuing quest to understand our place in the cosmos.

Public Perception

One of the most significant but often overlooked aspects of the Skylab Program was its impact on the public’s perception of space exploration. For the first time, people could see astronauts living and working in space, not just walking on the moon. The images and video footage sent back to Earth had a profound effect, allowing the public to feel more connected to the astronauts and their mission.

Skylab and Space Education

Aside from the scientific advancements and the technical knowledge garnered from the Skylab Program, it also played a pivotal role in inspiring and educating the public about space science. As the first U.S. space station, Skylab offered an unprecedented view into life in space, with astronauts conducting live broadcasts showing their daily routines, scientific experiments, and remarkable views of Earth. This outreach was integral in fostering public interest in space exploration and emphasizing the importance of scientific literacy.

Moreover, Skylab also helped to nurture the next generation of scientists and engineers. The Student Project, which was part of Skylab’s educational program, allowed high school students to propose experiments to be conducted aboard the station. The winning experiments involved studies in six different areas – physics, biology, astronomy, solar physics, human perception, and materials science. This initiative not only enriched student learning but also encouraged young minds to think innovatively and consider careers in STEM (Science, Technology, Engineering, and Mathematics) fields.

The Future of Space Stations Post-Skylab

Skylab’s influence extended far beyond its operational lifespan and its own program. The lessons learned from the Skylab missions informed the design and operation of subsequent space stations, most notably the International Space Station (ISS), a multinational project representing the collaborative efforts of NASA, Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada).

The knowledge gained from Skylab’s experiments on the effects of long-duration spaceflight on the human body have been invaluable to the ISS program. Understanding how to effectively manage resources, maintain astronaut health, and conduct scientific research in space are all challenges that were first tackled during the Skylab missions.

The future of space stations looks even more promising, with plans for lunar orbit stations like the Lunar Gateway, a small spaceship that will orbit around the Moon and provide access to the lunar surface. Commercial entities like SpaceX and Blue Origin also have plans for their own space stations, potentially marking a new era of commercial space travel and habitation.

International Collaboration

Moreover, Skylab set a strong precedent for international cooperation in space. It proved that humans could live and work in space for extended periods, paving the way for the multinational collaboration that led to the creation of the ISS.

Skylab’s Influence on Commercial Space Ventures

Skylab’s legacy also extends to the burgeoning field of commercial spaceflight. Today, private companies such as Northrop Grumman, Blue Origin, and Vast are planning or have already launched their own space stations. The concept of a commercially-operated space station, unthinkable during the era of Skylab, has become a reality in part due to the technological and operational lessons learned from the Skylab program.

These companies are building upon the knowledge and experience gained from government-operated space programs, and are also contributing new technologies and innovations of their own. For instance, SpaceX has pioneered the development of reusable rockets, which can dramatically reduce the cost of space travel.

The advent of commercial space stations could open up numerous opportunities, from space tourism and manufacturing to scientific research and technology development. The dream of making space more accessible, which began with programs like Skylab, is becoming closer to reality.

Skylab Program Facts


Year Event
1965 NASA announced the Apollo Applications Program (AAP), intending to find uses for Apollo hardware beyond the lunar missions. This eventually led to the concept of Skylab.
1966 Conceptual design studies for a space station began, led by the Manned Spacecraft Center, which is now known as the Johnson Space Center.
1969 The project was officially named Skylab.
February 14, 1970 The Skylab program was officially announced by NASA.
1970 The three Skylab crews were selected. Modifications to the Saturn V launch vehicle and the Apollo spacecraft for the Skylab missions began.
May 14, 1973 Skylab was launched from Kennedy Space Center. However, during launch, the station lost its micrometeoroid shield and one of its main solar panels, leading to a critical situation due to high temperatures and insufficient power.
May 25, 1973 The first crewed mission (Skylab 2) was launched to repair and inhabit Skylab, ten days after the initial launch. Astronauts Charles “Pete” Conrad, Joseph Kerwin, and Paul Weitz successfully deployed a sunshade to cool the station and freed the remaining solar panel.
June 22, 1973 The Skylab 2 crew safely returned to Earth after spending 28 days in space.
July 28, 1973 The Skylab 3 mission was launched, carrying astronauts Alan Bean, Jack Lousma, and Owen Garriott. They spent 59 days in space, conducting further repairs and various scientific experiments.
September 25, 1973 The Skylab 3 crew safely returned to Earth.
November 16, 1973 The Skylab 4 mission was launched, with astronauts Gerald Carr, William Pogue, and Edward Gibson. They spent 84 days in space, setting a new record for the longest human spaceflight.
February 8, 1974 The Skylab 4 crew safely returned to Earth, marking the end of the last manned mission to Skylab.
1974-1979 Skylab remained in orbit unmanned. Ground controllers periodically adjusted its orientation to minimize atmospheric drag and maximize the solar panels


Mission Launch Date Crew Members Duration Notable Achievements
Skylab 1 May 14, 1973 Uncrewed Station operational but unmanned Launch of the Skylab station, sustained damage during launch
Skylab 2 May 25, 1973 Charles “Pete” Conrad, Joseph Kerwin, Paul Weitz 28 days Repaired the station, conducted various experiments
Skylab 3 July 28, 1973 Alan Bean, Jack Lousma, Owen Garriott 59 days Conducted extensive scientific and medical experiments, performed two spacewalks
Skylab 4 November 16, 1973 Gerald Carr, William Pogue, Edward Gibson 84 days Set a record for the longest crewed spaceflight, staged the so-called “mutiny”, performed four spacewalks


Nine astronauts served on the Skylab missions, carrying out a variety of scientific experiments, making significant repairs to the space station, and setting new records for duration in space. Their contributions greatly expanded our understanding of living and working in space and laid the groundwork for future space missions.

Charles “Pete” Conrad

Charles “Pete” Conrad Jr. was born on June 2, 1930, in Philadelphia, Pennsylvania. He graduated from Princeton University in 1953 with a degree in Aeronautical Engineering. Conrad joined the U.S. Navy, where he trained as a pilot and eventually became a flight instructor. He joined NASA in 1962 as part of the second group of astronauts, often known as the “New Nine.” Before his Skylab mission, Conrad commanded Gemini 5 and 11 and Apollo 12, the second manned mission to land on the moon. Conrad commanded the first crewed Skylab mission, Skylab 2, in 1973.

Joseph Kerwin

Joseph Peter Kerwin was born on February 19, 1932, in Oak Park, Illinois. He received a Doctor of Medicine degree from Northwestern University Medical School in 1957. He served in the U.S. Navy as a flight surgeon before being selected by NASA in 1965 as part of the first group of scientist-astronauts. Kerwin served as the science pilot for Skylab 2, becoming the first American physician to go to space.

Paul Weitz

Paul Joseph Weitz was born on July 25, 1932, in Erie, Pennsylvania. After graduating from Pennsylvania State University in 1954, he joined the U.S. Navy and trained as a pilot. He later attended the U.S. Naval Postgraduate School, earning a Master of Science degree in Aeronautical Engineering. Selected as a NASA astronaut in 1966, Weitz served as the pilot for the Skylab 2 mission. Later, he commanded the first flight of the space shuttle Challenger in 1983.

Alan Bean

Alan LaVern Bean was born on March 15, 1932, in Wheeler, Texas. After earning a Bachelor of Science degree from the University of Texas at Austin, he joined the U.S. Navy, where he trained as a pilot and test pilot. Bean was selected as a NASA astronaut in 1963. Prior to his Skylab mission, he served as the lunar module pilot on Apollo 12, becoming the fourth person to walk on the moon. Bean was the commander of the Skylab 3 mission.

Jack Lousma

Jack Robert Lousma was born on February 29, 1936, in Grand Rapids, Michigan. He earned a Bachelor of Science degree in Aeronautical Engineering from the University of Michigan and a Master of Science degree in Aeronautical Engineering from the U.S. Naval Postgraduate School. He served as a Marine Corps aviator and test pilot before being selected as a NASA astronaut in 1966. Lousma was the pilot of the Skylab 3 mission.

Owen Garriott

Owen Kay Garriott was born on November 22, 1930, in Enid, Oklahoma. He earned a Bachelor of Science degree in Electrical Engineering from the University of Oklahoma and a Master of Science and Ph.D. in Electrical Engineering from Stanford University. Selected as a NASA astronaut in 1965, Garriott was a science pilot on the Skylab 3 mission. He later flew on the space shuttle Columbia for the STS-9 mission.

Gerald Carr

Gerald Paul Carr was born on August 22, 1932, in Denver, Colorado. He earned a Bachelor of Science degree in Mechanical Engineering from the University of Southern California and a Master of Science degree in Aeronautical Engineering from Princeton University. After serving as a Marine Corps pilot and engineer, he was selected as a NASA astronaut in 1966. He served as the commander of the Skylab 4 mission, which was his only spaceflight.

William Pogue

William Reid Pogue was born on January 23, 1930, in Okemah, Oklahoma. He received a Bachelor of Science degree from Oklahoma Baptist University and a Master of Science degree in Mathematics from Oklahoma State University. Pogue served as a U.S. Air Force pilot and test pilot before being selected as a NASA astronaut in 1966. He was the pilot for the Skylab 4 mission, his only spaceflight.

Edward Gibson

Edward George Gibson was born on November 8, 1936, in Buffalo, New York. He earned a Bachelor of Engineering degree in Mechanical Engineering from the University of Rochester, and a Master of Science degree and Ph.D. in Engineering and Physics from the California Institute of Technology. Selected as a NASA astronaut in 1965, Gibson served as the science pilot for the Skylab 4 mission.


The Skylab Program, despite its initial setbacks and short-lived operation, was a triumph for NASA and the United States’ space program. It represented a fundamental shift from short-term space travel to the possibility of sustained human presence in space. The wealth of scientific, technical, and medical knowledge gleaned from the Skylab missions continues to influence current and future space exploration endeavors.