Antimatter-Hunting Experiment Delivered for Last Space Shuttle Flight

An ambitious experiment to search for antimatter galaxies and elusive dark matter has taken a step closer to its planned launch on NASA's last scheduled space shuttle flight next year.

The experiment, called the Alpha Magnetic Spectrometer, was expected to arrive at NASA's Kennedy Space Center in Florida today to be prepped for its journey to the International Space Station aboard NASA's final planned shuttle flight. Liftoff is currently slated for Feb. 26, 2011.

NASA spokesperson Allard Beutel told SPACE.com the huge experiment would arrive at the Florida space center around 11:30 a.m. EDT (1530 GMT).

The AMS, a 15,000-pound (6,800-kg) cosmic-ray detector, was loaded onto a U.S. Air Force Galaxy transport aircraft in Geneva on Wednesday. The AMS experiment has a reported cost of nearly $2 billion, according to press reports.

The detector had been undergoing some final modifications at the particle-physics laboratory CERN, along the Swiss-French border.

Big new magnet

Project scientists have spent the last few months replacing the spectrometer's vital superconducting magnet with a long-lasting one that will give the experiment a longer life on the space station.

"The entire AMS collaboration is delighted by this departure, because it marks a crucial milestone for the experiment. We are getting close to the space shuttle launch and the moment when our detector will finally be installed on board the ISS," said the project's leader Samuel Ting, a Nobel laureate physicist with MIT, in a statement. "The detector’s construction phase is now finished and we are eager for the data collection phase to begin."

More than 600 physicists from 16 countries and nearly 60 institutes are involved in the experiment, which is a collaboration of NASA and the U.S. Department of Energy, among others.

Ting and his colleagues decided on the magnet swap earlier this year after the International Space Station received a life extension through at least 2020.

The spectrometer's original magnet was designed to rely on a supply of cryogenic liquid helium to stay cool, which would eventually run out. The new magnet is designed to be permanent.

NASA originally canceled the shuttle mission to deliver the AMS to the space station following the 2003 Columbia shuttle disaster. But Congress later approved funding for the flight.

Hunting for antimatter

Antimatter is like a mirror image of regular matter; each "normal" particle is thought to have an antimatter counterpart. Positrons, for example, are the antimatter versions of electrons; when the two come together, they immediately annihilate each other.

While scientists know antimatter exists, they have yet to directly observe dark matter, but have long inferred its existence because of its gravitational pull on the universe.

AMS has the potential to help scientists confirm the existence of dark matter, and perhaps to help find entire galaxies made of antimatter using its cosmic ray detector.

Cosmic rays consist of high-energy particles that emerge from catastrophic events such as supernovas. The particles are typically absorbed by Earth's atmosphere, so a space-based detector has a better chance of spotting them, researchers have said.

AMS will analyze these cosmic rays to determine if they're normal matter such as protons and electrons, or something more exotic. The detection of anti-electrons could signal the existence of dark matter, researchers said.

AMS' mission is similar to that of the cosmic-ray detector PAMELA, an Italian satellite launched in 2006 that may have detected dark matter's signature. But the detector on AMS will be even more sensitive, project scientists said.

"The launch of AMS detector is very timely," project member Roberto Petronzio, president of the Italian National Institute for Nuclear Physics, said in a statement. "Today we are well aware of our ignorance of the universe’s most abundant constituents and we still challenge the puzzle of matter-antimatter asymmetry. Furthermore, recent results from the Pamela experiment suggest scenarios for important discoveries for AMS."

• The Strangest Things in Space
• Video: Dark Matter in 3-D
• Space Station Experiment to Hunt Antimatter Galaxies