NASA SuperTIGER Balloon Launching Over Antarctica Will Hunt Rare Cosmic Rays

NASA's SuperTIGER aboard its balloon. NASA/BPO

A team of scientists is camped out in Antarctica to launch a giant balloon in hopes of better understanding the rarest type of cosmic rays that hit Earth—particles of relatively heavy elements like zinc and tin. The project, called Super Trans-Iron Galactic Element Recorder and nicknamed SuperTIGER, is supposed to launch by Sunday, but the team is at the mercy of the harsh Antarctic weather and has already been delayed from its first prospective lift-off.

Weather is deteriorating. Coming back inside. Scrubbed for today. #Antarctica 🇦🇶

— SuperTIGER (@SuperTigerLDB) December 8, 2017

Cosmic rays is a general term for all sorts of particles that hit Earth. The vast majority of those particles are protons, or hydrogen atoms that have lost their sole electron. But a tiny portion of those are the cores of other, much heavier atoms, which are born during gigantic celestial fireworks.

There are two types of fireworks involved: supernovae, which occur when a large star explodes, and neutron star collisions, when two products of supernovae then merge with each other. SuperTIGER is trying to identify which cosmic ray particles come from which source and clarify the details of how they get from there to here.

In particular, SuperTIGER is looking for the cores of elements that fall between neon and zirconium on the periodic table of the elements—a range that includes metals like aluminum, cobalt and copper. It's also taking measurements about a heavier set, including metals like silver and tin, but the team behind the instrument expects those data to be a little less definitive.

Once it lifts off, SuperTIGER will lazily circle Antarctica counterclockwise, thanks to winds that trap it over the continent. It flies as high as 127,000 feet above Earth, protecting it from a confusing background chatter produced as cosmic rays hit Earth's atmosphere and break down into smaller particles. At 127,000 feet, SuperTIGER is above 99.5 percent of the atmosphere, so it sails above all that noise, isolating truly galactic particles.

Read more: Timing Was Everything for Discovery of Gold-Producing Neutron Star Collision 130 Million Light-Years Away

This isn't SuperTIGER's first flight—the giant space balloon flew for 55 days during its first mission in 2012 and 2013. Then the balloon spent two years sitting out on Antarctica's ice before scientists were able to fetch it and prepare it for another mission. And the mission design itself is an upgrade on a similar, less advanced detector named TIGER that flew in the late 1990s and early 2000s.

But since those missions, scientists have finally been able to confirm that ultra-heavy particles, like gold and platinum are produced by neutron star collisions. Combining that knowledge with new SuperTIGER data could give scientists the best picture yet of where heavy elements Earth can't produce come from.