SuperTIGER team members Brian Rauch, Jason Link and Nathan Walsh join NASA Blueshift's Sara Mitchell for a Skype conversation about the instrument's science, technology and upcoming launch from McMurdo Station, Antarctica.
Scientists in Antarctica are preparing to loft a NASA balloon-borne instrument to collect information on cosmic rays, high-energy particles from beyond the solar system that enter Earth's atmosphere every moment of every day. The instrument, called the Super Trans-Iron Galactic Element Recorder (SuperTIGER), is designed to study rare heavy nuclei, which hold clues about where and how cosmic rays attain speeds up to nearly the speed of light.
The most common cosmic ray particles are protons (hydrogen nuclei), making up roughly 90 percent, followed by helium nuclei (8 percent) and electrons (1 percent). The remainder contains the nuclei of other elements, with dwindling numbers of heavy nuclei as their masses rise. With SuperTIGER, researchers are looking for the rarest of the rare -- so-called ultra-heavy cosmic ray nuclei beyond iron, from cobalt to barium.
These elements are formed in some of the most extreme environments in the cosmos -- outflows from massive stars, supernova explosions, and mergers of neutron stars. Learning more about the distribution of the heavy cosmic rays will help astronomers further narrow down the places and processes forming them.
When SuperTIGER’s balloon reaches its maximum altitude, near 130,000 feet (40,000 meters), its envelope has expanded to a diameter of 460 feet (140 meters) -- big enough to spin a football field in its center.
Cosmic rays are protons, electrons, and atomic nuclei traveling at up to nearly the speed of light originating from beyond the solar system. SuperTIGER seeks the heaviest nuclei, ranging from neon to barium, that make up less than 1 percent of the cosmic ray population. The distribution of these heavy nuclei enable scientists to hone ideas about where cosmic rays originate and how they’re boosted to high energies.
Launching balloons in Antarctica during the austral summer has two big advantages. A persistent high-pressure system forms a unique counterclockwise circulation called a polar vortex in the upper atmosphere above the continent. These upper-level winds guide balloons around the continent, letting scientists recover their instruments near the launch site once the mission concludes. Constant daylight during the Antarctic summer minimizes day-night temperature fluctuations, which is an important factor for long-duration flights.
Brian Rauch (right), a Research Assistant Professor at Washington University in St. Louis, and Washington University graduate student Nathan Walsh work on SuperTIGER in Payload Building 2 at McMurdo Station, Antarctica. The instrument is scheduled to begin it’s second flight in December.
On Dec. 1, SuperTIGER was brought onto the deck of Payload Building 2 at McMurdo Station, Antarctica, to test communications in preparation for its second flight. Mount Erebus, the southernmost active volcano on Earth, appears in the background.