Encyclopedia Astronautica
1973.11.17 - Skylab Orbital Workshop activation by the crew of Skylab 4.


The reactivation included the reservicing of the airlock module primary coolant loop. The commander and pilot experienced symptoms resembling motion sickness during the initial three days of the visit, and flight plan activities were adjusted accordingly. Crew health was good thereafter.

The medical experiments conducted during the first and second visits were continued during the third visit to assess the effects of the space visit on the crewmen. Some changes were made, and many new medical detailed test objectives were added.

EREP observations were conducted throughout the visit. Thirty-nine data passes were performed with the full complement of instruments operating, and several additional data passes were made for special purposes such as instrument calibration. Although the data acquisition sites were mostly concentrated in the United States, Mexico, and South America, data were also obtained while over Europe, Africa, Asia, and Australia. In addition to the EREP observations, about 850 visual observations were made, and more than 2000 photographs were taken by the crew using hand-held cameras to document specific areas of interest on Earth.

The Apollo telescope mount was operated by the crew for a total time of approximately 519 hours, with over 337 hours of solar, stellar, and Comet Kohoutek data being obtained. Some of the significant accomplishments were obtaining coverage of the Comet Kohoutek, a solar eclipse, the brightest coronal transient observed during the Skylab Program, and two solar flares which included flare rise.

Twenty-eight experiments in the fields of astrophysics, engineering, and technology were included in the third visit, and 235 crew man-hours were devoted to their performance. More than 200 man-hours were devoted to Comet Kohoutek observations, with six special experiments plus the ATM instruments.

Orbital activities included four periods of EVA totaling approximately 221/4 hours. The first EVA was accomplished 22 November and lasted 6 hours 34 minutes. The primary purpose of the activity-installation of film magazines in the ATM cameras-was accomplished satisfactorily. Other tasks accomplished included performing corrective maintenance on the experiment S193 (microwave radiometer/scatterometer and altimeter) antenna, deploying panels of experiment D024 (thermal control coatings), deploying impact detectors of experiment S149 (particle collection), deploying detector modules of experiment S228 (trans-uranic cosmic rays), and deploying collector assemblies of experiment S230 (magnetospheric particle composition).

The second and third EVAs were conducted on Christmas day and 29 December to take photographs of the Comet Kohoutek; prior to and after perihelion. The instruments for experiments S201 (extreme ultraviolet camera) and T025 (coronagraph contamination experiment) were used for this purpose. Experiment S020 (X-ray/ultraviolet solar photography) was also conducted on the second and third EVAs. Other tasks performed during the extravehicular activity consisted of replacing film magazines in the ATM cameras, pinning open the door of experiment S082A (extreme ultraviolet spectroheliograph), manually repositioning the filter wheel on experiment S054 (X-ray spectrographic telescope), and retrieving experiment S149 (particle collection) impact detectors. The duration of the second EVA was 6 hours 54 minutes; the third 3 hours 29 minutes.

The fourth and final EVA was performed on 3 February 1974. The major tasks accomplished consisted of retrieval of the ATM film, an additional performance of experiment S020, and performance of experiment T 025. Other tasks consisted of retrieval of modules, panels, assemblies, and samples that were to be returned to the ground for analysis, and deployment of cassettes and panels for potential retrieval in the future. The duration of the fourth EVA was 5 hours 19 minutes.

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