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

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

, the first American orbital

space station A space station (or orbital station) is a spacecraft which remains orbital spaceflight, in orbit and human spaceflight, hosts humans for extended periods of time. It therefore is an artificial satellite featuring space habitat (facility), habitat ...

. 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), Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functi ...

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 (, 43,3 ...

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, aviator, and test pilot who commanded the Apollo 12 mission, on which he became the third person to walk on t ...

, Joseph P. Kerwin, Paul J. Weitz 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. Its crew was the first space station occupants ever to return safely to Earth – the only previous space station occupants, the crew of the 1971 Soyuz 11 mission that had crewed the

Salyut 1 Salyut 1 (), also known as DOS-1 (Durable Orbital Station 1), was the world's first space station. It was launched into low Earth orbit by the Soviet Union on April 19, 1971. The Salyut programme, ''Salyut'' program subsequently achieved five m ...

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 * Henry W. Hartsfield, Jr * William E. Thornton * Richard H. Truly

Mission parameters

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

SA-206 *Spacecraft:

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

-116 *

Perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

: 428 km *

Apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

: 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 Eart ...

: 50° * Period: 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

Skylab Station Viewed by Skylab 2 Command Module - GPN-2000-001709

The

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

used a KH-8 Gambit 3 to photograph the damaged station. On May 25, Skylab 2 lifted from LC-39B, the first

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, so nothing happened and the launch proceeded as planned. This glitch was traced to a modification of the pad electrical equipment and corrective steps were taken to prevent it from happening again. On reaching the station, Conrad flew their

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

(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, and 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, 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 at the

Marshall Space Flight Center Marshall Space Flight Center (officially the George C. Marshall Space Flight Center; MSFC), located in Redstone Arsenal, Alabama (Huntsville, Alabama, Huntsville postal address), is the Federal government of the United States, U.S. government's ...

. 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 a relatively intense, localized emission 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 ot ...

with the

Apollo Telescope Mount The Apollo Telescope Mount, or ATM, was a crewed Sun, 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, ultraviolet, and visible light. The ATM was ...

; 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 splashing 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 mission patch was designed by

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

, 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'' 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.

Spacecraft location

The Skylab 2 command module is displayed at the National Museum of Naval Aviation,

Pensacola, Florida Pensacola ( ) is a city in the Florida panhandle in the United States. It is the county seat and only incorporated city, city in Escambia County, Florida, Escambia County. The population was 54,312 at the 2020 United States census, 2020 census. ...

. Different for earlier Apollo modules, Skylab ones had white paint on the sunward side to help with spacecraft thermal management. 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 Saturn IB Successful space missions