Skylab 3 Captured Dramatic Solar Prominences in August 1973

Summary: Skylab 3 captured dramatic solar prominences in August 1973 with the first United States space station’s sophisticated Apollo Telescope Mount (ATM).

Skylab 3 scientist-pilot Owen Garriott’s accidental photograph of a solar eruption named the elbow prominence (top of solar disk) occurred Thursday, Aug. 9, 1973, occurred while the former Stanford University professor and researcher was observing a small solar flare flashing near the sun’s top limb (left of prominence’s roots): Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library

Skylab 3 captured dramatic solar prominences in August 1973 with the eight state-of-the-art solar observational instruments housed in the first United States space station’s sophisticated solar observatory, the Apollo Telescope Mount (ATM).

The Skylab 3 mission operated from liftoff Saturday, July 28, 1973, to splashdown Tuesday, Sept. 25, 1973, as the National Aeronautics and Space Administration’s (NASA) second of three manned missions to the Skylab space station.

Fourth moonwalker and mission commander Alan Bean (March 15, 1932-May 26, 2018), scientist-pilot Owen Garriott (Nov. 22, 1930-April 15, 2019) and mission pilot Jack Lousma (born Feb. 19, 1936) composed the Skylab 3 mission’s crew. For Garriott, the mission’s solar observations revisited his specialty, ionospheric physics, which he researched and taught from 1961 to 1965 in his pre-NASA career as assistant, then associate, professor at California’s prestigious Stanford University.

As a region electrically charged by cosmic and solar radiation, the ionosphere stretches from the upper mesosphere to the upper troposphere, the third and fourth of Earth’s five principal atmospheric layers. A paper on “Solar Flare Effects in the Ionosphere,” which he had co-authored with three Stanford University colleagues, was published, after Garriott’s acceptance in 1965 into NASA’s scientist-astronaut program, in the Dec. 1, 1967, issue of JGR Journal of Geophysical Research.

The Apollo Telescope Mount primarily attached exteriorly to the space station’s Multiple Docking Adapter (MDA), with additional supports on the adjacent section, the Airlock Module (AM).  The crew accessed the ATM’s command and display (C & D) console at its station within the Multiple Docking Adapter.

Solar prominences numbered among the multiplicity of solar phenomena studied via the space station’s operations. Prominences arise on the solar surface, where they are anchored in the photosphere, the lowest layer of the solar atmosphere. These bright, large gaseous features erupt from the surface and extend outward, slicing through the chromosphere, into the corona, the outer layer of the sun’s atmosphere.

On Thursday, Aug. 9, Owen Garriott accidentally photographed a prominence during his observation of a solar flare. The solar flare’s sudden, explosive flash of intense brightness occurred near the top limb (edge of the solar disk), beneath arch formed by the elbow-shaped prominence.

In A New Sun: The Solar Results From Skylab, published by NASA in 1979, spectral lines astronomer John Allen “Jack” Eddy (March 25, 1931-June 10, 2009) considered the timescale of the elbow prominence. “The eruption began as a low-lying prominence that soared upward; here, after about 20 min. it has reached a dizzying altitude of more than 600,000 km above the Sun-- almost twice the distance that separates Earth and the Moon” (page 156).

Garriott’s image captured the erupting prominence in ultraviolet light of ionized helium. Eddy’s report placed the elbow prominence’s temperature “. . . in the range of 30,000 to 90,000 K -- far cooler and denser than the million-Kelvin corona through which we see it pass.” The severing of magnetic field lines in the chromosphere, the sun’s middle atmospheric layer, from their roots in the photosphere shaped the elbow prominence’s twisted structure.

Skylab’s ultraviolet instruments captured another immense eruption Sunday, Aug. 26, at 23:45 (11:45 p.m.) Central Daylight Time (Monday, Aug. 27, at 04:45 Coordinated Universal Time). John Eddy explained: “The Sun enjoys a midnight fling, casting off 6 billion metric tons of filmy outer dress at speeds of more than 100 km/s” (page 159). Only about 10 minutes after leaving the solar surface, the eruption achieved an arch of more than 300,000 kilometers above the sun. The Apollo Telescope Mount recorded the arching reach just 15 minutes shy of midnight, Houston time.

Ultraviolet light of ionized helium suggested a temperature range of 30,000 to 90,000 Kelvin for the midnight eruption. Eddy found that the reveal of “coiled, magnetic springs” by the “clearly twisted” form told “. . . the secret of its expulsion from the Sun.”

The transient phenomena pushed ahead coronal material to create “. . . an even larger transient disturbance in the outer corona. . .” The eruption’s exuberance “. . . eventually dissipated in interplanetary space.”

The takeaways for the Skylab 3 mission’s capture of dramatic solar prominences in August 1973 via the Skylab space station’s sophisticated Apollo Telescope Mount are that Skylab 3 scientist-pilot Owen Garriott’s observations via Skylab’s Apollo Telescope Mount revisited his pre-NASA career as a Stanford University professor and researcher of solar effects on Earth’s ionosphere and that Garriott accidentally photographed the “elbow prominence” while his focus was on a solar flare flashing beneath the elbow-shaped eruption.

“The Sun enjoys a midnight fling”; immense eruption’s timescale of about 10 minutes between solar surface departure and soaring arch, recorded by the Apollo Telescope Mount’s ultraviolet instrumentation at 11:45 p.m. Houston time, Sunday, Aug. 26, 1973; J.A. Eddy, A New Sun: The Solar Results From Skylab (1979), page 159: Public Domain, via NASA History

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Skylab 3 scientist-pilot Owen Garriott’s accidental photograph of a solar eruption named the elbow prominence (top of solar disk) occurred Thursday, Aug. 9, 1973, occurred while the former Stanford University professor and researcher was observing a small solar flare flashing near the sun’s top limb (left of prominence’s roots): Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details-9606705

“The Sun enjoys a midnight fling”; immense eruption’s timescale of about 10 minutes between solar surface departure and soaring arch, recorded by the Apollo Telescope Mount’s ultraviolet instrumentation at 11:45 p.m. Houston time, Sunday, Aug. 26, 1973; J.A. Eddy, A New Sun: The Solar Results From Skylab (1979), page 159: Public Domain, via NASA History @ https://history.nasa.gov/SP-402/ch7.htm

For further information:

Eddy, John A. “Chapter 7: The Active Sun.” A New Sun: The Solar Results From Skylab: 126-177. Edited by Rein Ise. Prepared by George C. Marshall Space Flight Center. NASA SP-402. Washington DC: National Aeronautics and Space Administration, 1979.
Available via NASA History @ https://history.nasa.gov/SP-402/contents.htm

Garriott, Owen K.; Aldo V. da Rosa; Michael J. Davis; and O.G. (Oswald Garrison) Villard Jr. “Solar Flare Effects in the Ionosphere.” JGR Journal of Geophysical Research, vol. 72, issue 23 (Dec. 1, 1967): 6099-6103.
Available via Wiley Online American Geophysical Union (AGU) publications @ https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JZ072i023p06099

Hathaway, David H. “The Photosphere.” NASA Marshall Space Flight Center Solar Physics Group > Solar Structure.
Available @ https://solarscience.msfc.nasa.gov/surface.shtml

Hitt, David; Owen Garriott; and Joe Kerwin. Homesteading Space: The Skylab Story. Featuring the In-Flight Diary of Alan Bean. Lincoln NE: University of Nebraska Press, 2008.
Available via Google Books @ https://books.google.com/books/about/Homesteading_Space.html?id=sR5Cm_zeIekC

Marriner, Derdriu. “Arabella and Anita Spun First Space Webs in August 1973 at Skylab.” Earth and Space News. Wednesday, July 31, 2013.
Available @ https://earth-and-space-news.blogspot.com/2013/07/arabella-and-anita-spun-first-space.html

Marriner, Derdriu. “First Web in Space Was Spun in 1973 by Common Cross Spider Arabella.” Earth and Space News. Wednesday, Aug. 5, 2020.
Available @ https://earth-and-space-news.blogspot.com/2020/08/first-web-in-space-was-spun-in-1973-by.html

Marriner, Derdriu. “Fourth Moonwalker Alan Bean Commanded Skylab 3 July to September 1973.” Earth and Space News. Wednesday, July 22, 2020.
Available @ https://earth-and-space-news.blogspot.com/2020/07/fourth-moonwalker-alan-bean-commanded.html

Marriner, Derdriu. “Owen Garriott and Jack Lousma Did Second EVA Aug. 24, 1973, at Skylab.” Earth and Space News. Wednesday, Aug. 19, 2020.
Available @ https://earth-and-space-news.blogspot.com/2020/08/owen-garriott-and-jack-lousma-did.html

Marriner, Derdriu. “Skylabbers Owen Garriott and Jack Lousma First Spacewalked Aug. 6, 1973.” Earth and Space News. Wednesday, Aug. 12, 2020.
Available @ https://earth-and-space-news.blogspot.com/2020/08/skylabbers-owen-garriott-and-jack.html

Marriner, Derdriu. “Two Mummichog Minnows Became First Fish in Space in 1973 Via Skylab 3.” Earth and Space News. Wednesday, July 29, 2020.
Available @ https://earth-and-space-news.blogspot.com/2020/07/two-mummichog-minnows-became-first-fish.html

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UCAR Center for Science Education. “The Ionosphere.” UCAR (University Corporation for Atmospheric Research) Center for Science Education (SciEd) > Learning Zone > Atmosphere > Layers of Earth’s Atmosphere

Zell, Holly, ed. “Earth’s Atmospheric Layers.” NASA > Mission Pages > Sun-Earth > Science. Jan. 22, 2013. Last updated Aug. 7, 2017.
Available @ https://www.nasa.gov/mission_pages/sunearth/science/atmosphere-layers2.html

Zell, Holly, ed. “What Is a Solar Prominence?” NASA > Content > Goddard Space Flight Center > FAQ. March 6, 2015. Last updated Aug. 7, 2017.
Available @ https://www.nasa.gov/content/goddard/what-is-a-solar-prominence