Editing Skylab 4 (section)

==Mission highlights==
[[File:Sl3-113-1587.jpg|thumb|upright|One of the dummies left behind by the Skylab 3 crew to be found by the Skylab 4 crew]]
[[File:Skylab 4 trash.jpg|thumb|upright|Bill Pogue (left) and Gerald Carr pass trash through an airlock to Skylab's waste disposal tank.]]
[[File:Kohoutek-uv.jpg|thumb|upright|alt=Kohoutek-uv|False color image of Comet Kohoutek photographed with the far-ultraviolet electrographic camera during a Skylab spacewalk on December 25, 1973]]
[[File:Skylab Solar flare.jpg|right|thumb|Solar prominence photographed December 19, 1973, by the [[Apollo Telescope Mount]]]]

The all-rookie astronaut crew arrived aboard Skylab to find three figures dressed in flight suits. Upon closer inspection, they found these were dummies with Skylab 4 mission emblems and name tags which had been left there by [[Al Bean]], [[Jack Lousma]], and [[Owen Garriott]] at the end of [[Skylab 3]].<ref>{{cite web|title = Photo-sl3-113-1587|url = http://spaceflight.nasa.gov/gallery/images/skylab/skylab3/html/sl3-113-1587.html|archive-url = https://web.archive.org/web/20150508042241/http://spaceflight.nasa.gov/gallery/images/skylab/skylab3/html/sl3-113-1587.html|url-status = dead|archive-date = May 8, 2015|website = spaceflight.nasa.gov|access-date = May 21, 2015}}</ref>

Things got off to a bad start after the crew attempted to hide Pogue's early [[space sickness]] from flight surgeons, a fact discovered by mission controllers after downloading onboard voice recordings.  Astronaut office chief [[Alan B. Shepard]] reprimanded them for this omission, saying they "had made a fairly serious error in judgement."<ref>{{Cite news |url=https://www.nytimes.com/1973/11/18/archives/skylab-astronauts-are-reprimanded-in-1st-day-aboard-learned-from.html |title=Skylab Astronauts Are Reprimanded In 1st Day Aboard |last=Wilford |first=John Noble |date=November 18, 1973 |work=The New York Times |access-date=July 11, 2018}}</ref>

The crew had problems adjusting to the same workload level as their predecessors when activating the workshop. The crew's initial task of unloading and stowing the thousands of items needed for their lengthy mission also proved to be overwhelming.<ref>{{Cite news |url=https://www.nytimes.com/1973/11/19/archives/astronauts-try-to-make-up-time-skylab-3-lehind-schedule-as-result.html |title=Astronauts Try to Make Up Time |date=November 19, 1973| agency=Associated Press |work=[[The New York Times]] |access-date=July 11, 2018}}</ref> The schedule for the activation sequence dictated lengthy work periods with a large variety of tasks to be performed, and the crew soon found themselves tired and behind schedule.

Seven days into their mission, a problem developed in the Skylab [[Control moment gyroscope|gyroscopic]] [[Spacecraft attitude control|attitude control]] system, which threatened to bring an early end to the mission. Skylab depended upon three large gyroscopes, sized so that any two of them could provide sufficient control and maneuver Skylab as desired. The third acted as a backup in the event of failure of one of the others.<ref>{{Cite news |url=https://www.nytimes.com/1973/11/24/archives/a-skylab-gyroscope-fails-leaving-only-2-for-control.html |title=A Skylab Gyroscope Fails, Leaving Only 2 for Control |date=November 24, 1973 |work=The New York Times |access-date=July 11, 2018 |agency=Associated Press}}</ref> The gyroscope failure was attributed to insufficient [[lubrication]]. Later in the mission, a second gyroscope showed similar problems,<ref>{{Cite news |url=https://www.nytimes.com/1973/12/08/archives/gyro-on-skylab-is-erratic-officials-are-not-alarmed.html |title=Gyro on Skylab Is Erratic; Officials Are Not Alarmed |date=December 8, 1973 |work=The New York Times |access-date=July 11, 2018 |agency=Associated Press }}</ref><ref>{{Cite news |url=https://www.nytimes.com/1974/01/04/archives/skylab-gyroscope-falters-puzzling-ground-engineers.html |title=Skylab Gyroscope Falters, Puzzling Ground Engineers |date=January 4, 1974 |work=The New York Times |access-date=July 11, 2018 |agency=United Press International}}</ref> but special temperature control and load reduction procedures kept the second one operating, and no further problems occurred.

On [[Thanksgiving (United States)|Thanksgiving Day]], Gibson and Pogue accomplished a 6{{frac|2}} hour spacewalk. The first part of their spacewalk was spent deploying experiments and replacing film in the solar observatory. The remainder of the time was used to repair a malfunctioning antenna.  During the experience, Gibson remarked, "Boy if this isn't the great outdoors!  Inside, you're just looking out through a window.  Here, you're right in it."<ref>{{Cite news |url=https://www.nytimes.com/1973/11/23/archives/2-astronauts-fix-skylab-antenna-space-walk-for-repairs-and.html |title=Two Astronauts fix Skylab Antenna |date=November 23, 1973 |work=The New York Times |access-date=July 11, 2018 |agency=Associated Press }}</ref> The crew reported that the food was good, but slightly bland. The quantity and type of food consumed was rigidly controlled because of their strict diet. Although the crew would have preferred to use more condiments to enhance the taste of the food, and the amount of salt they could use was restricted for medical purposes, by the third mission the NASA kitchen had increased the availability of condiments, and salt and pepper were in liquid solutions (granular salt and pepper brought aboard by the second crew was little more than "air pollution").<ref>Erling, John (2013) [http://www.voicesofoklahoma.com/wp-content/uploads/2013/10/Pogue_Transcript.pdf Interview with William Pogue] {{Webarchive|url=https://web.archive.org/web/20200531033357/http://www.voicesofoklahoma.com/wp-content/uploads/2013/10/Pogue_Transcript.pdf |date=May 31, 2020 }}. Voices of Oklahoma. p. 33.</ref>

On December 13, the crew sighted [[Comet Kohoutek]] and trained the solar observatory and hand-held cameras on it. They gathered spectra on it using the [[Far Ultraviolet Camera/Spectrograph]].<ref>{{cite web|title=SP-404 Skylab's Astronomy and Space Sciences|date=January 1979 |url=https://history.nasa.gov/SP-404/ch4.htm|access-date=May 14, 2013|archive-url=https://web.archive.org/web/20041113100704/https://history.nasa.gov/SP-404/ch4.htm|archive-date=November 13, 2004 |last1=Lundquist |first1=C. A. }}</ref>  They continued to photograph it as it approached the Sun. On December 30, as it swept out from behind the Sun, Carr and Gibson spotted it as they were performing a spacewalk.

As Skylab work progressed, the astronauts complained of being pushed too hard, and ground controllers complained they were not getting enough work done.  NASA determined major contributing factors were a large number of new tasks added shortly before launch with little or no training, and searches for equipment out of place on the station.<ref name="NatGeo74"/><ref>{{Cite news |url=https://www.nytimes.com/1973/12/12/archives/lethargy-of-skylab-3-crew-is-studied.html |title=Lethargy of Skylab 3 Crew Is Studied |work=The New York Times |agency=Reuters |date=December 12, 1973 |access-date=July 11, 2018}}</ref><ref>{{Cite news |url=https://www.nytimes.com/1973/11/25/archives/skylab-crew-takes-day-off-for-rest.html |title=Skylab Crew Takes Day Off for Rest |date=November 25, 1973 |work=The New York Times |access-date=July 11, 2018 |agency=Associated Press}}</ref>  There was a radio conference to air frustrations<ref>{{Cite news |url=https://www.nytimes.com/1973/12/31/archives/astronauts-debate-work-schedules-with-controllers.html |title=Astronauts Debate Work Schedules With Controllers |date=December 31, 1973 |work=The New York Times |access-date=July 11, 2018 |agency=Associated Press }}</ref> which led to the workload schedule being modified, and by the end of their mission the crew had completed more work than originally planned.

Skylab 4 involved several scientific observations. The crew spent many hours studying the Earth. Carr and Pogue alternately crewed controls, operating the sensing devices which measured and photographed selected features on the Earth's surface. Gibson and the other crew made solar observations, recording about 75,000 new telescopic images of the Sun. Images were taken in the [[X-ray]], [[ultraviolet]], and visible portions of the spectrum.<ref name="NatGeo74"/><ref>[https://web.archive.org/web/20090716025431/https://www.jsc.nasa.gov/Bios/htmlbios/gibson-eg.html Edward G. Gibson Biographical Data]. National Aeronautics and Space Administration, Lyndon B. Johnson Space Center</ref>

As the end of their mission drew closer, Gibson continued his watch of the solar surface. On January 21, 1974, an active region on the Sun's surface formed a bright spot which intensified and grew.<ref name="NatGeo74">{{Cite journal |last=Canby |first=Thomas |date=October 1974 |title=Skylab, Outpost on the Frontier of Space |url=https://archive.nationalgeographic.com/?iid=54304#folio=468 |journal=National Geographic Magazine |volume=146 |pages=441–493}}{{rp|468}}</ref> Gibson quickly began filming the sequence as the bright spot erupted. This film was the first recording from space of the birth of a [[solar flare]].

The crew also photographed the Earth from orbit. Despite instructions not to do so, the crew (perhaps inadvertently) photographed [[Area 51]], causing a minor dispute between various government agencies as to whether the photographs showing this secret facility should be released. In the end, the picture was published along with all others in NASA's Skylab image archive, but remained unnoticed for years.<ref>[http://www.thespacereview.com/article/1010/1 Secret Apollo]. ''The Space Review''. November 26, 2007</ref>

The Skylab 4 astronauts completed 1,214 Earth orbits and four EVAs totaling 22 hours, 13 minutes. They traveled 34.5 million miles (55,500,000&nbsp;km) in 84 days, 1 hour and 16 minutes in space. Skylab 4 was the last Skylab mission; the station fell from orbit in 1979.

The three astronauts had joined NASA in the mid-1960s, during the [[Apollo program]], with Pogue and Carr becoming part of the likely crew for the cancelled [[Apollo 19]]. Ultimately none of the crew of Skylab 4 flew in space again, as none of the three were selected for [[Apollo–Soyuz]] and all of them retired from NASA before the first [[Space Shuttle]] launch. Gibson, who had trained as a [[NASA Astronaut Group 4|scientist-astronaut]], resigned from NASA in December 1974 to do research on Skylab solar physics data, as a senior staff scientist with [[The Aerospace Corporation]] of Los Angeles, California.