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Scanning the Southern Skies: SOFIA Flies from French Polynesia

Columbia, Maryland—July 20,  2021. To study celestial objects best observed from the Southern Hemisphere, NASA’s Stratospheric Observatory for Infrared Astronomy, SOFIA,will be conducting its flights from Fa’a’ā International Airport, outside Papeete, Tahiti, French Polynesia, where it arrived on July 19, 2021. 

SOFIA landing in French Polynesia Image credit: NASA/SOFIASOFIA landing in French Polynesia. Image credit: DSI / Florian Beherens

SOFIA regularly deploys to the Southern Hemisphere for a few weeks to observe objects only visible from this Hemisphere. Due to high demand from scientists for targets observable from the southern hemisphere, this year SOFIA is planning more missions to better serve the scientific community. The new deployment site from French Polynesia, instead of New Zealand (closed because of COVID restrictions), will allow researchers to continue groundbreaking science from the Southern Hemisphere despite the pandemic.

An added bonus for flying during this time of year, during the Southern Hemisphere’s winter, is that the water vapor in the Earth’s upper atmosphere is much lower during these months in these latitudes, compared to the Northern Hemisphere’s summer. Among the many objects best seen from Southern Hemisphere latitudes, SOFIA will be looking at the central-most regions of our galaxy, the Milky Way.

Instruments on board SOFIA

The SOFIA team is sending two instruments to French Polynesia, the German Receiver at Terahertz Frequencies (GREAT) and the High-resolution Airborne Wideband Camera-Plus, or HAWC+, which will observe our galactic center as well as many other targets. SOFIA will also observe Earth’s atmosphere, to support monitoring and studying the upper atmosphere important for climate change research.

Currently, 20 flights are planned with the German Receiver at Terahertz Frequencies, or GREAT, instrument, which is operated by the Max Planck Institute of Radio Astronomy in Bonn and the University of Cologne, both in Germany. Additionally, the SOFIA team plans to use the High-resolution Airborne Wideband Camera-Plus, or HAWC+, (https://www.nasa.gov/ames/image-feature/one-of-a-kind-camera-added-to-sofia) to observe important astronomical targets visible from the southern skies. At the end of August, the High-resolution Airborne Wideband Camera Plus will be installed and flown for an expected total of 12 flights.

Observations and Activities

During the GREAT flight series, the team will search for gases that can reveal the presence of cosmic rays, highly energetic charged particles that stream through our Milky Way galaxy. When a hydrogen atom combines with another element, such as argon or oxygen, simple molecules called hydrides are formed, some of which can be used to find cosmic rays. While cosmic rays can be detected directly within our solar system, astronomers know much less about their presence elsewhere in space. By measuring the concentration of hydride molecules, SOFIA’s observations will help researchers understand how common cosmic rays are in different parts of our galaxy, providing clues about the origin of these mysterious particles. [https://www.sofia.usra.edu/science/proposing-and-observing/proposal-calls/cycle-8/selected-proposals/abstracts#38].

SOFIA will also make new measurements of atomic oxygen in Earth’s atmosphere, building on the success of previous observations (https://www.nasa.gov/feature/sofia-offers-new-way-to-study-earth-s-atmosphere). Atomic oxygen, a particular form of unbonded oxygen, plays an important role in cooling the upper atmosphere and, therefore, is used to estimate temperatures in this region. Climate models predict that increasing greenhouse gases will raise temperatures in the lower atmosphere yet decrease temperatures in the mesosphere. These continued observations will allow a team of German scientists to monitor the seasonal and latitudinal variability of atomic oxygen, leading to a more accurate understanding of the relationship between the lower and upper atmosphere. SOFIA is the only observatory capable of measuring atomic oxygen in this region of Earth’s atmosphere and these observations are important for understanding climate change.

With the HAWC+ instrument SOFIA will make the first observations of the “Study of Interstellar Magnetic Polarization: a Legacy Investigation of Filaments.” https://www.sofia.usra.edu/science/data/legacy-programs/study-interstellar-magnetic-polarization-legacy-investigation-filaments. This new program focuses on the observation of high gas density, thread-shaped regions called filaments, where most stars form. The scientific team will make maps of star forming regions relatively close to Earth. These maps will help constrain the relative importance of self–gravity, turbulence, and magnetic fields. The most exciting aspect of this project is the wide variety of spatial scales that will be observed by SOFIA. The overall goal of this year’s deployment is to obtain better scientific understanding of the role of magnetic fields in star formation from large star–forming regions down to the scale of planet– forming disks.

The SOFIA team also plans to observe the galactic center using HAWC+ to understand the magnetic fields in our own galaxy. This work will complement the previous successful SOFIA Legacy Program which mapped much of the Milky Way using another SOFIA instrument (list the instrument in parenthesis, at least?). These multiple views of our galaxy will help scientists better understand the role of magnetic fields in star formation and in the regions of the galaxy closest to the central supermassive black hole. https://www.nasa.gov/feature/sofia-reveals-new-view-of-milky-way-s-center


Deploying to and operating from French Polynesia involves relocating the SOFIA aircraft and observing instruments, storage and cooling equipment, and of course moving critical personnel for several weeks and sometimes months at a time. It requires an active partnership and high level of coordination with local authorities, airport facilities, and workforce, as well as local vendors. This year, for the first time, SOFIA’s southern deployment will be based at the Fa’a International Airport in Tahiti, French Polynesia. 

Dr. William Reach, SOFIA’s Associate Director for Science Operations, said “Deploying to the Southern Hemisphere is an important annual event for SOFIA, allowing us to observe the central part of the Milky Way as well as other galaxies that are not accessible from our home base in California. I’m looking forward to getting the Observatory back to the southern skies and completing some high-priority observations that astronomers have requested.”

Detailed flight plans for the southern deployment series will be posted in the next week on the SOFIA Science Center website [https://www.sofia.usra.edu/science/proposing-and-observing/flights/cycle-9].

Media inquires about SOFIA’s southern deployment should be sent to the NASA Ames newsroom.


SOFIA is a joint project of NASA and the German Space Agency at DLR. DLR provides the telescope, scheduled aircraft maintenance, and other support for the mission. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

About USRA
Founded in 1969, under the auspices of the National Academy of Sciences at the request of the U.S. Government, the Universities Space Research Association (USRA) is a nonprofit corporation chartered to advance space-related science, technology, and engineering. USRA operates scientific institutes and facilities, and conducts other major research and educational programs. USRA engages the university community and employs in-house scientific leadership, innovative research and development, and project management expertise. More information about USRA is available at www.usra.edu.