The crowning glory of the International Space Station has nothing to do with preparing humans to live on the moon or finding a cure for Salmonella. It's a particle detector designed to hunt for an antimatter universe.
NASA is planning a shuttle mission in 2011 to ferry the 7.5-ton detector, known as the Alpha Magnetic Spectrometer, to the station. For a while, it looked as if the device would be stuck on Earth, but its trip into orbit now looks assured.
"I have learned in the 15 years working with space experiments you are only confident once you are on the space station taking data," said Samuel Ting, the Nobel Prize physicist who leads the AMS team.
"My main job at this moment is to make sure (in) the final phase of the assembly of the detector, that nothing goes wrong," Ting told Discovery News.
Ting, who was a co-discoverer of the first complex antimatter particle, said he's been wondering for more than 45 years about the missing mass that should have been created along with regular matter at the birth of the universe.
"At the beginning, if you have an electron, you must have a positron. If [you] have a proton, you must have an anti-proton. In other words, there must be equal amounts of matter and anti-matter," Ting said.
"It always troubled me; where's the universe made out of antimatter? That was basically one of the reasons we proposed this experiment," he added. "This is somewhat of a definitive experiment to see whether [an] antimatter universe really exists or not."
AMS was eliminated from the shuttle's manifest following the 2003 Columbia accident, when the United States decided to retire the fleet for safety and cost reasons, upon completion of the space station. NASA is developing new spaceships that can travel to the moon as well as the station.
The outcry over AMS' cancellation was sharp, particularly because most of its $1.5-billion price tag was picked up by a huge and still-growing international partnership that is backing the program. NASA's role was to fly AMS to space and install it outside the station.
In 2008, Congress restored the mission -- and followed up with funding.
"AMS is a fitting experiment for the International Space Station," said Trent Martin, who is overseeing the project for NASA at the Johnson Space Center in Houston. "It's very big science. It's international cooperation at its best."
This report has been updated by msnbc.com to reflect the scheduling of the AMS delivery mission aboard the shuttle Endeavour in February 2011.