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365DaysDate: April 9, 2009

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Title: SkyLab and the Apollo Telescope Mount

Podcaster: Josh Fuchs and Travis Rasor

Organization: Rhodes College Department of Physics
http://www.rhodes.edu/academics/7560.asp
NASA IYA Student Ambassador Program
http://www.spacegrant.org/niya/

Description: SkyLab was the first space station and hosted three crews of astronauts in the early 1970’s. In this podcast, we will focus on what we learned from the second of the manned missions, SkyLab 2, and the Apollo Telescope Mount. The Apollo Telescope Mount was the solar observatory on SkyLab, which provided a wealth of information about the Sun. Topics discussed will include coronal holes and x-ray bright points.

Bio: Josh is a second-year Physics student at Rhodes College and also a NASA IYA Student Ambassador.

Travis Rasor is a third-year Computer Science student at Rhodes College. Both are avid amateur astronomers.

Today’s Sponsor: This episode of “365 Days of Astronomy” is sponsored by Scientific Frontline: A not for profit educational science news service. Visit us at www.sflorg.com.

Transcript:

Josh Fuchs: Hello and welcome to the April 9th podcast of 365 Days of Astronomy. My name is Josh Fuchs and I am a second-year physics student at Rhodes College in Memphis, TN and a NASA IYA Student Ambassador.

Travis Rasor: And I am Travis Rasor, a third-year computer science student also at Rhodes. We are going to be talking today about the first space station, NASA’s SkyLab, and some of the interesting discoveries that resulted from this mission.

Travis: The SkyLab missions had two goals: to prove that humans could live and work in space for extended periods of time and to expand our knowledge of solar astronomy.

Josh: SkyLab housed 3 three-man crews for a total of 171 days, 13 hours. The total number of man-hours in space and hours spent in extravehicular activities completed during the SkyLab missions exceeded the combined totals of all the world’s previous space flights up to that point.

Travis: SkyLab was launched on the back of a Saturn V rocket from NASA’s Kennedy Space Center on May 14, 1973. Shortly after that on May 25, the first SkyLab crew of 3 launched to rendezvous with SkyLab, repaired a solar array torn off during launch, cooled SkyLab to a working temperature, and conducted solar, Earth, and medical experiments.

Josh: The final SkyLab mission occurred from November 1973 through February 1974. Some more maintenance was performed on SkyLab and numerous solar observations were made. After the last SkyLab crew left, the station was left orbiting the Earth until it re-entered the atmosphere on July 11, 1979. We would like to take some time now to talk about the second manned mission to SkyLab.

Travis: SkyLab 2 (SLM-2) was the second manned mission to SkyLab, SkyLab 1 being the launch of SkyLab, not the first manned mission. It was launched July 28th, 1973, and the Astronauts returned to earth September 28th, 1973. The mission lasted 59 days, 11 hours and 9 minutes, went through 858 orbits around the earth, and had 1084 astronaut-utilization hours performing scientific experiments. There were three spacewalks. The goals of the mission were solar observations, medical research, and investigations into Earth resources.

Josh: One of the interesting occurrences that took place during the mission was a leak that developed in the Apollo Control Service Module’s reaction control system. The crew docked safely with the station; however a second Apollo spacecraft was prepped for a rescue mission, a first for the space program. The rescue mission was never needed, however, as the leaks were eventually fixed.

Travis: Space habitation and medical experimentation were very important during the mission, with assessments made of the crew’s ability to complete tasks in space, along with the ease of use of the station and the habitability of the crew quarters and the station as a whole.
Extensive medical testing was performed in the mission. This testing was more of a continuation of the tests performed on SkyLab 2, however the two month length of SkyLab 3 was double that of SkyLab 2 and further studies of life in space were performed. Most notably was the observation of muscle mass fluctuations in space, as well as an investigation of the “puffy face syndrome” which was related to the imbalance of fluids that occurs in low gravity and was first observed on SkyLab 2. The mission and its investigations were able to give extensive information on fluid distribution and balance in the body, and fluidic shifts that occur during space flight.

Josh: Along with medical experiments, much solar research was performed, but more on that later. 
Also notable was that many of these experiments performed during the mission were designed and prepped by High School students from across the United States. These experiments involved investigations into astronomy, physics. and biology, including – but not limited to – topics of x-rays from Jupiter, spider web formation, neutron analysis, and in-vitro immunology.
The Apollo Telescope Mount was one of the four principal parts of SkyLab. It was a solar observatory that was housed in a canister attached to the rest of the structure by a large rack. The canister attached to the rack through large gimbal rings on a bearing that allowed the entire canister to rotate about its axis. Along with the main observing equipment there was also an array of four large solar panels providing power to the observing platform. The internals of the canister were arranged in a cruciform structure that ran the entire length, dividing the space into quadrants and forming the optical bench to which the instrumentation was attached. The observatory also had an advanced digital computer that was much more powerful than would be expected for the time and allowed the crew to execute commands quickly enough to preserve the focus of the high resolution optics.

Travis:  The observatory had eight separate solar experiments: two X-ray telescopes, an X-ray and extreme ultraviolet camera, an ultraviolet spectroheliometer, an ultraviolet and extreme ultraviolet spectroheliograph, a white light coronagraph, and two hydrogen-alpha telescopes.
Using all this equipment, astronauts on SkyLab made several interesting discoveries. One of these was the discovery of solar coronal holes. Coronal holes are visible as dark regions in the corona, and are spots where the coronal material is quite thin. Coronal holes were observed to rotate very rigidly and maintain their shape through several solar rotations in spite of the variance in the rotation rate of the surface of the sun. Along with coronal holes, X-ray bright spots were also discovered. These bright spots are very small brightenings that only exist for a short time which are actually most visible within a coronal hole.

Josh: Rhodes College has a personal and interesting connection with the SkyLab story. A number of Rhodes physics students worked with Professor Bob MacQueen at the High Altitude Observatory in Boulder, CO, after the mission ended. They primarily worked with images from the white-light coronagraph on SkyLab that produced an artificial solar eclipse and allowed the students to recover more than 35,000 film images of the solar corona. The instrument operated under both astronaut and ground control and so monitored the solar corona throughout both manned and unmanned mission periods. The work that was completed by the Rhodes students was published in a variety of journals.

Travis: The SkyLab missions successfully achieved their goals. SkyLab, along with MIR, laid the basis for the International Space Station by proving that humans could live and work in space for extended periods of time.

Josh: The solar results from the Apollo Telescope Mount provided a foundation for the myriad of solar research occurring today. Current NASA missions studying the sun include the Solar and Heliospheric Observatory- SOHO, the Transition Region and Coronal Explorer-Trace, Hinode, the Solar Terrestrial Relations Observatory -STEREO, the Solar Dynamics Observatory, the Solar Anomalous and Magnetospheric Particle Explorer -SAMPEX, and the Solar Radiation and Climate Experiment –SORCE.

Travis: For more information about Skylab and other NASA missions visit the NASA website at nasa.gov. We’d also like to thank Bob MacQueen, Professor Emeritus, Rhodes College for his assistance in the preparation of this program. On behalf of myself and my co-host, thank you for listening and goodnight.

End of podcast:

365 Days of Astronomy
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