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NASA has selected a science mission that will untangle the complexities of the interstellar medium, and map out large sections of the plane of our Milky Way galaxy and the Large Magellanic Cloud. NASA, ESA, and Hubble Heritage Team

NASA announced Saturday that it had, as part of its Explorers Program, selected a science mission to measure emissions from the interstellar medium within our galaxy. The mission, named Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO), will cost roughly $40 million and is scheduled for launch in 2021 from the McMurdo station in Antarctica.

“GUSTO will provide the first complete study of all phases of the stellar life cycle, from the formation of molecular clouds, through star birth and evolution, to the formation of gas clouds and the re-initiation of the cycle,” Paul Hertz, astrophysics division director at NASA’s Science Mission Directorate said in a statement. “NASA has a great history of launching observatories in the Astrophysics Explorers Program with new and unique observational capabilities. GUSTO continues that tradition.”

The interstellar medium is the material that fills the space between stars in galaxies. Almost 99 percent of the interstellar medium is made of gas (mostly hydrogen), while the remaining 1 percent is dust. Studying and mapping the interstellar medium is crucial for understanding how stars form due to gravitational collapse of gas and dust.

This is where the GUSTO mission comes in. The observatory, which will consist of a telescope affixed with carbon, oxygen and nitrogen emission line detectors carried on board an Ultralong-Duration Balloon (ULDB) will not only map out the distribution of interstellar medium in the Milky Way, but also within its satellite galaxy — the Large Magellanic Cloud.

“This data will help scientists determine the life cycle of interstellar gas in our Milky Way galaxy, witness the formation and destruction of star-forming clouds, and understand the dynamics and gas flow in the vicinity of the center of our galaxy,” NASA said in the statement.

Since 1958, NASA has so far launched over 90 missions as part of its Explorers Program, which it says aims to enhance public awareness and appreciation for space science.

“NASA's Astrophysics Explorers Program requested proposals for mission of opportunity investigations in September 2014,” the space agency said. “A panel of NASA and other scientists and engineers reviewed two mission of opportunity concept studies selected from the eight proposals submitted at that time, and NASA has determined that GUSTO has the best potential for excellent science return with a feasible development plan.”