Skylab 2 (also SL-2 and SLM-1) was the first crewed mission to

Skylab Skylab was the first United States space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974. It was operated by three separate three-astronaut crews: Skylab 2, Skylab 3, and Skylab 4. Major operations ...

, the first American orbital

space station A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station ...

. The mission was launched on an

Apollo command and service module The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother sh ...

by a

Saturn IB The Saturn IB (also known as the uprated Saturn I) was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage (, 43 ...

rocket on May 25, 1973, and carried NASA astronauts

Pete Conrad Charles "Pete" Conrad Jr. (June 2, 1930 – July 8, 1999) was an American NASA astronaut, aeronautical engineer, naval officer and aviator, and test pilot, and commanded the Apollo 12 space mission, on which he became the third person to ...

, Joseph P. Kerwin,

Paul J. Weitz Paul Joseph Weitz (July 25, 1932 – October 22, 2017) was an American naval officer and aviator, aeronautical engineer, test pilot, and NASA astronaut, who flew into space twice. He was a member of the three-man crew who flew on Skylab 2, ...

to the station. The name Skylab 2 also refers to the vehicle used for that mission. The Skylab 2 mission established a twenty-eight-day record for human spaceflight duration. Furthermore, its crew were the first space station occupants ever to return safely to Earth – the only previous space station occupants, the crew of the 1971

Soyuz 11 Soyuz 11 (russian: link=no, Союз 11, lit=Union 11) was the only crewed mission to board the world's first space station, Salyut 1 ( Soyuz 10 had soft-docked, but had not been able to enter due to latching problems). The crew, Georgy Dob ...

mission that had crewed the

Salyut 1 Salyut 1 (DOS-1) (russian: Салют-1) was the world's first space station launched into low Earth orbit by the Soviet Union on April 19, 1971. The Salyut program followed this with five more successful launches of seven more stations. The f ...

station for twenty-four days, died upon reentry due to unexpected cabin depressurization. The crewed Skylab missions were officially designated Skylab 2, 3, and 4. Miscommunication about the numbering resulted in the mission emblems reading "Skylab I", "Skylab II", and "Skylab 3" respectively.

Crew

Backup crew

Support crew

Robert L. Crippen Robert Laurel Crippen (born September 11, 1937) is an American retired naval officer and aviator, test pilot, aerospace engineer, and retired astronaut. He traveled into space four times: as Pilot of STS-1 in April 1981, the first Space Shu ...

* Henry W. Hartsfield, Jr *

William E. Thornton William Edgar Thornton (April 14, 1929 – January 11, 2021) was an American NASA astronaut. He received a Bachelor of Science degree in physics from University of North Carolina and a doctorate in medicine, also from UNC. He flew on ''Challe ...

Richard H. Truly Richard Harrison Truly (born November 12, 1937) is a retired Vice admiral (United States), vice admiral in the United States Navy, a former fighter pilot, engineer, astronaut, and was the eighth NASA Administrator, administrator of the NASA, Natio ...

Mission parameters

*Mass: 19,979 kg *Maximum altitude: 440 km *Distance: 18,536,730.9 km *Launch vehicle:

Perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any el ...

: 428 km *

Apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any el ...

: 438 km *

Inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Ea ...

: 50° *

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

: 93.2 min *Soft dock: May 26, 1973 – 09:56 UTC *Undocked: May 26, 1973 – 10:45 UTC *Time docked: 49 minutes *Hard dock: May 26, 1973 – 15:50 UTC *Undocked: June 22, 1973 – 08:58 UTC *Time docked: 26 days, 17 hours, 2 minutes

Space walks

;''Weitz'' — EVA 1 (stand up EVA — CM side hatch) :Start: May 26, 1973, 00:40 UTC :End: May 26, 01:20 UTC :Duration: 40 minutes ;''Conrad and Kerwin'' — EVA 2 :Start: June 7, 1973, 15:15 UTC :End: June 7, 18:40 UTC :Duration: 3 hours, 25 minutes ;''Conrad and Weitz'' — EVA 3 :Start: June 19, 1973, 10:55 UTC :End: June 19, 12:31 UTC :Duration: 1 hour, 36 minutes

Mission highlights

The

station suffered significant damage on its May 14 launch: its micrometeorite shield, and one of its primary

solar array A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and ...

s had torn loose during launch, and the remaining primary solar array was jammed. Without the shield which was designed to also provide thermal protection, Skylab baked in the Sun, and rising temperatures inside the workshop released toxic materials into the station's atmosphere and endangered on-board film and food. The first crew was supposed to launch on May 15, but instead had to train practicing repair techniques as they were developed by the engineers.Benson, Charles Dunlap and William David Compton.
Living and Working in Space: A History of Skylab
'. NASA publication SP-4208. Ground controllers purged the atmosphere with pure nitrogen four times, before refilling it with the nitrogen/oxygen atmosphere for the crew. The secret

National Reconnaissance Office The National Reconnaissance Office (NRO) is a member of the United States Intelligence Community and an agency of the United States Department of Defense which designs, builds, launches, and operates the reconnaissance satellites of the U.S. fe ...

used a KH-8 Gambit 3 to photograph the damaged station. On May 25, Skylab 2 lifted from LC-39B, the first Saturn IB launch in almost five years and only the second-ever launch from Pad 39B. Booster performance was nominal except for one momentary glitch that could have threatened the mission – when the Commit signal was sent to the Saturn at ignition, the instrument unit sent a command to switch the launch vehicle from internal to external power. This would have shut down the Saturn's electrical system, but not the propulsion system, and likely cause the disaster scenario of an uncontrollable booster, requiring the Launch Escape System to be activated and the Command Module pulled away to safety, followed by Range Safety destroying the errant launch vehicle. However, the duration of the cutoff signal was less than one second, too short a time for the electrical relay in the booster to be activated, thus nothing happened and the launch proceeded as planned. This glitch was traced to a modification of the pad electrical equipment and corrective steps were subsequently taken to prevent it from happening again. On reaching the station, Conrad flew their

Apollo Command/Service Module The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother sh ...

(CSM) around it to inspect the damage, then soft-docked with it to avoid the necessity of station keeping while the crew ate, and flight controllers planned the first repair attempt. Then they undocked so that Conrad could position the CSM by the jammed solar panel, so that Weitz could perform a stand-up EVA, trying to free the array by tugging at it with a 10-foot hooked pole, while Kerwin held onto his legs. This failed, and consumed a significant amount of the Skylab's nitrogen maneuvering fuel to keep it steady in the process. The crew then attempted to perform the hard dock to Skylab, but the capture latches failed to operate. After eight failed attempts, they donned their pressure suits again and partially dis-assembled the CSM's docking probe; the next attempt worked. Once inside the station, the crew deployed a collapsible parasol through the small scientific airlock to act as a sunshade. (This approach was suggested and designed by NASA's "Mr. Fix It" Jack Kinzler, who was awarded the

NASA Distinguished Service Medal The NASA Distinguished Service Medal is the highest award that can be bestowed by the National Aeronautics and Space Administration of the United States. The medal may be presented to any member of the federal government, including both milita ...

for the effort.) Successful deployment of the sunshade dropped inside temperatures to sustainable levels. Skylab 2 Deorbiting

Two weeks later, Conrad and Kerwin performed a second EVA, finally freeing the stuck solar panel and increasing the electrical power to the workshop. They had prepared for this repair by practicing in the

Neutral Buoyancy Simulator The Neutral Buoyancy Simulator was a neutral buoyancy pool located at NASA's George C. Marshall Space Flight Center (MSFC). Engineers and astronauts developed hardware and practiced procedures in this tank from its completion in 1968 through its ...

at the

Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC), located in Redstone Arsenal, Alabama (Huntsville postal address), is the U.S. government's civilian rocketry and spacecraft propulsion research center. As the largest NASA center, MSFC's firs ...

. Without power from the panel, the second and third Skylab missions would have been unable to perform their main experiments, and the station's critical battery system would have been seriously degraded. During this EVA, the sudden deployment of the solar panel structure caused both astronauts to be flung from the station's hull, testing their nerves as well as the strength of their safety tethers. After recovering their composure, both astronauts returned to their positions on the station and completed the EVA.David J. Shayler, FBIS, ''Walking in Space'', 2004, p. 213, Praxis Publishing Ltd. For nearly a month they made further repairs to the workshop, conducted medical experiments, gathered solar and Earth science data, and performed a total of 392 hours of experiments. The mission tracked two minutes of a large

solar flare A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other sol ...

with the

Apollo Telescope Mount The Apollo Telescope Mount, or ATM, was a crewed solar observatory that was a part of Skylab, the first American space station. It could observe the Sun in wavelengths ranging from soft X-rays, ultra-violet, and visible light. The ATM was man ...

; they took and returned some 29,000 frames of film of the sun. The Skylab 2 astronauts spent 28 days in space, which doubled the previous U.S. record. The mission ended successfully on June 22, 1973, when Skylab 2 splashed down in the Pacific Ocean 9.6 km from the recovery ship USS ''Ticonderoga''. Skylab 2 set the records for the longest duration crewed spaceflight, greatest distance traveled and greatest mass docked in space. Conrad set the record for most time in space for an astronaut.

Mission insignia

The Skylab 1 patch was designed by

Kelly Freas Frank Kelly Freas (August 27, 1922 – January 2, 2005) was an American science fiction and fantasy artist with a career spanning more than 50 years. He was known as the "Dean of Science Fiction Artists" and he was the second artist inducted b ...

, a well-known artist highly regarded in the science fiction community, who was suggested to NASA by science fiction author and editor

Ben Bova Benjamin William Bova (November 8, 1932November 29, 2020) was an American writer and editor. During a writing career of 60 years, he was the author of more than 120 works of science fact and fiction, an editor of ''Analog Science Fiction and Fac ...

. The insignia features Skylab above the earth with the sun in the background. In an article for ''

Analog Science Fiction/Science Fact ''Analog Science Fiction and Fact'' is an American science fiction magazine published under various titles since 1930. Originally titled ''Astounding Stories of Super-Science'', the first issue was dated January 1930, published by William C ...

'' magazine, Freas said, "Among the suggestions the astronauts had made was the idea of a solar eclipse as seen from Skylab. It soon became clear that this idea would solve several problems at once: it pointed up the solar study function of Skylab, it would give me the large circular shape of the Earth as counterpoint to the angularity of the cluster, and it would establish firmly the connection of Skylab to the Earth. In addition, it would give a chance to get the necessary high contrast for good visibility of the tiny finished patch. ... I made several studies of cloud patterns on the planet, reducing them finally to very conventionalized swirls. The Skylab cluster was simplified and simplified again, till it became simply a black form with a white edgelight to set it off."

Gallery

Image:Skylab 2,Kerwin in OWS.jpg, Kerwin blows water droplets from a straw Image:Skylab 2 - Weitz assists Kerwin with blood pressure cuff.jpg, Weitz assists Kerwin with a

blood pressure cuff A sphygmomanometer ( ), a blood pressure monitor, or blood pressure gauge, is a device used to measure blood pressure, composed of an inflatable cuff to collapse and then release the artery under the cuff in a controlled manner, and a mercury o ...

Spacecraft location

The Skylab 2 command module is displayed at the

National Museum of Naval Aviation The National Naval Aviation Museum, formerly known as the National Museum of Naval Aviation and the Naval Aviation Museum, is a military and aerospace museum located at Naval Air Station Pensacola, Florida. Founded in 1962 and moved to its curr ...

Pensacola, Florida Pensacola () is the westernmost city in the Florida Panhandle, and the county seat and only incorporated city of Escambia County, Florida, United States. As of the 2020 United States census, the population was 54,312. Pensacola is the principal c ...

. Image:Skylab2-1.jpg, Skylab 2 CM Image:Skylab2-2.jpg, Skylab 2 CM Image:Skylab2-3.jpg, Skylab 2 CM interior

References

External links

Skylab: Command service module systems handbook, CSM 116 – 119 (PDF) April 1972

Skylab Saturn 1B flight manual (PDF) September 1972

Multimedia

Onboard flight film from the Skylab 2 mission
{{Use American English, date=January 2014 1973 in spaceflight Extravehicular activity Human spaceflights Skylab program Spacecraft launched in 1973 Spacecraft which reentered in 1973 Spacecraft launched by Saturn rockets Pete Conrad