NASA is preparing to start an experiment called GUSTO (short for Galactic/Extragalactic ULDB Terahertz Spectroscopic Observatory) to collect data used to create 3D maps of parts of the Milky Way. The GUSTO experiment involves a telescope that will float 120,000 feet above Antarctica in a high-altitude balloon for at least 55 days, absorbing high-frequency radio waves that penetrate the interstellar medium of the universe (gas, dust, radiation) and other materials that make up the space between stars.
NASA has an interesting guide to scientific balloons explaining the zero-pressure and superpressure balloons it uses for such missions:
https://www.nasa.gov/scientificballoons/types-of-balloons/
GUSTO will search for signatures of carbon, oxygen and nitrogen in the interstellar medium, searching for clues about how stars and planets form—specifically, what allows space particles to clump together to form the molecular clouds that precede star formation. According to NASA, the balloon will launch from McMurdo Station in Antarctica "no earlier than December 21."
Chris Walker of the University of Arizona, who leads the GUSTO project, said GUSTO is well-suited to the task of picking up the terahertz frequencies at which particles travel. "Having the radio system we built, we can turn a knob and tune to the frequency of those lines," he said in a NASA statement. "If we hear something, we know it's them, those atoms and molecules."
NASA said the mission will also "reveal the 3D structure of the Large Magellanic Cloud," a dwarf galaxy near the Milky Way that is visible to the naked eye from parts of Earth's southern hemisphere. The telescope will fly within the Antarctic atmospheric anticyclone, which will guide it around the pole during the mission.
GUSTO isn't the only balloon-based science instrument used by NASA. For more than 30 years, the agency has used balloons to launch scientific research payloads, sometimes weighing thousands of pounds. NASA representative Elizabeth Landau said that this special mission is the first mission of NASA's Explorer program. The Explorer program exists to "leverage innovative, streamlined and efficient management methods in the field of heliophysics and astrophysics science to provide frequent flight opportunities for world-class space science research."
Other GUSTO collaborators listed by NASA include the University of Arizona, the Johns Hopkins University Applied Physics Laboratory, the Netherlands Institute for Space Research, the Massachusetts Institute of Technology, the Jet Propulsion Laboratory and the Smithsonian Astrophysical Observatory.