When scientists first proposed building an instrument to comb cosmic radiation for antimatter particles, they imagined it would fly on the International Space Station.
Instead, a prototype to demonstrate proof of concept has evolved into a science program on its own, with backing from NASA and Japan, and rides to the edge of space aboard high-flying balloons. The high-flying research could help answer big questions about how the universe began and the pervasiveness of dark matter.
The Balloon-borne Experiment with Superconducting Spectrometer, or BESS, is a series of experiments that date back to 1993. It is built around a superconducting magnetic spectrometer, which is a common instrument in particle accelerators.
"The idea is if you have a charged particle that's traveling through a magnetic field, it'll be bent into a curved trajectory by the field," said John Mitchell, a NASA scientist at the Goddard Space Flight Center in Greenbelt, Md., and a lead investigator on the BESS program.
By tracking a particle's path through the field, scientists can determine how much energy it had, its electrical charge and its mass.
"You know everything there is to know about the particle. It's completely identified," Mitchell told Discovery News.
BESS started off as an idea for particle astrophysics facility known as Astromag, which was to be mounted on the space station. The project was dropped during station redesign efforts in the 1990s, though one experiment, the Alpha Magnetic Spectrometer, is scheduled to be flown to the orbital outpost next year.
Initial test flights on balloons proved successful. BESS found four antiprotons on its very first flight, spurring scientists to evolve the program from a technology demonstration to a full-fledge effort to detect elusive antimatter particles that date back to shortly after the universe's creation.
Slideshow 12 photos
Month in Space: January 2014
"We've actually done much of the science, maybe even most of the science, that was proposed for the original Astromag facility. It's been kind of an interesting evolution," Mitchell said.
Improvements to the device have left it now capable of finding about 500 antiprotons every day it flies, Mitchell said.
More recently, the scope of the work has expanded to look for fingerprints of tiny primordial black holes and other forms of dark matter.
Physicists theorize that these black holes, which have about as much mass as a mountain, could evaporate over time, ending their lives with a burst of radiation that could, in part, manifest as anti-particles.
With $1.4 million in new funding from NASA, announced last week, the BESS team plans to analyze data obtained during a successful three-week flight over Antarctica in 2007.
Following the instruments' retrieval and refurbishment, scientists hope to return BESS to the edge of space for an even more ambitious attempt to determine if any other type of antimatter particle exists, such as antihelium, which would answer a long-standing question about whether the Big Bang explosion that created the universe generated equal amounts of matter and antimatter.
If even a single particle of antihelium was discovered, it raises the prospect that entire galaxies of antimatter exist as well.
BESS was one of nine suborbital astrophysical research projects selected from 25 proposals for funding.
"We study how the universe works, how did we get here and are we alone -- is there life elsewhere in the galaxy," said Jon Morse, head of NASA's Astrophysics division. "We have suborbital and big missions all addressing this scientific portfolio."
