While space is largely devoid of matter, it does contain some dust and gas that floats between different stars, a material known as the interstellar medium. NASA has selected the Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) mission to conduct the first complete study of this matter, to better understand how it behaves.
Interstellar objects such as black holes, galaxies and stars get a lot of attention from scientists, but the interstellar medium isn’t a trivial thing to study: it makes up about 15 percent of the total mass in the Milky Way. 99 percent of that is free floating gas, mostly helium and hydrogen, and while space is still pretty empty, the vast distances mean that those small amounts add up.
The $40 million GUSTO mission, led by University of Arizona professor of astronomy Christopher Walker, will launch an Ultralong-Duration Balloon over Antarctica in 2021, which will carry a telescope that can detect nitrogen, carbon and oxygen spectral emissions. This equipment will allow the research team to study and map out parts of the Milky Way and the Large Magellanic Cloud.
Paul Hertz, the astrophysics division director in the Science Mission Directorate in Washington says, The mission will “provide the first complete study of all phases of the stellar life cycle”, “from the formation of molecular clouds, through star birth and progress, to the formation of gas clouds and the re-initiation of the cycle.” This will help scientists to understand the conditions in a better way that can ultimately lead to the formation of stars. “If we want to understand where we came from, we have to understand the interstellar medium, because 4.6 billion years ago, we were interstellar medium”, Walker explains.
The mission is awaited to launch in December 2021 from McMurdo Station in Antarctica. Depending on the weather, it will fly for up to 170 days. The balloon will fly at an altitude of 110,000 and 120,000 feet, which will allow researchers to avoid water vapor in the atmosphere that could obscure their readings. The team launched the Stratospheric Terahertz Observatory, a predecessor to GUSTO, which flew for three weeks over Antarctica in December 2016.