KENNEDY SPACE CENTER, Fla.--The Endeavour astronauts installed a $2 billion cosmic ray detector on the International Space Station today, a powerful magnet surrounded by a complex array of sensors that will study high-energy particles from the depths of space and time to look for clues about the formation and evolution of the universe.
"Thank you very much for the great ride and safe delivery of AMS to the station," radioed Sam Ting, the Nobel laureate who has managed the Alpha Magnetic Spectrometer project for more than 15 years. "Your support and fantastic work have taken us one step closer to realizing the science potential of AMS. With your help, for the next 20 years, AMS on the station will provide us a better understanding of the origin of the universe."
"Thank you, Sam," Endeavour commander Mark Kelly replied from the International Space Station. "I was just looking out the window of the orbiter and AMS looks absolutely fantastic on the truss. I know you guys are really excited and you're probably getting data and looking at it already."
Within two or three hours of installation and activation, the AMS was sending down a torrent of data, recording the passage of thousands of cosmic ray particles.
"The detector has 300,000 channels in the electronics, 650 microprocessors, and the detectors are aligned to (an accuracy of) one tenth of a human hair," Ting told reporters at a mission status briefing. "We immediately checked all the detectors, everything functioned properly. Not a single one was broken, not a single electronic channel was malfunctioning. Right away, we began to see an enormous amount of data coming down."
Ting showed off two sample graphs marking the passage of an electron with an energy of 20 billion electron volts and a carbon nucleus with an energy of 42 billion electron volts.
"This shows the detector functioned properly without any noticeable deformation whatsoever," he said. "We're very pleased. It took us 17 years to build this thing and (for the) duration of the space station we will be there, hopefully 10 to 20 years, and we hope...we will be able to make an important contribution to our understanding of the origin of the universe."
Astronauts Andrew Feustel and Roberto Vittori, working on the shuttle's aft flight deck, started the installation operation just before 3 a.m. ET, using Endeavour's 50-foot-long arm to slowly pull the 7.5-ton Alpha Magnetic Spectrometer from its perch at the back of the orbiter's payload bay.
After moving it to a point over the right side of the shuttle, pilot Gregory Johnson and Gregory "Taz" Chamitoff, operating the station's robot arm from a computer console inside the lab's multi-window cupola module, took over to move AMS into position for attachment on the upper right side of the station's power truss. A motorized claw mechanism in the truss then locked the detector in place on three guide pins just after 5:45 a.m.
A few minutes later,an umbilical assembly for power and data was mated by remote control. No other crew interaction was required and data collection began almost immediately.
"And Houston, from the cupola, I've got some great news," Chamitoff radioed just before 6 a.m. "The UMA mate is complete, AMS is now successfully installed. So huge congratulations to everyone on the AMS team. I'm sure Professor Ting and his group have been holding their breath. You guys can all start breathing again now."
How it works
AMS is roughly cube shaped, measuring 15 feet wide, 11 feet tall and 10 feet deep, tipping the scales at 15,251 pounds. Using a powerful magnet to bend the trajectories of high-energy cosmic rays--charged particles from supernovas, neutron stars, black holes and other cosmic enigmas--scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the the universe.
AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.
The AMS "really probes the foundations of modern physics," Ting said before launch. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."
Built at CERN, the European Organization for Nuclear Research, and managed by the U.S. Department of Energy, the $2 billion AMS is an international collaboration between 16 nations, 60 institutes and some 600 physicists. Ting, a soft-spoken Chinese-American physicist who shared the 1976 Nobel Prize in physics, is a tireless advocate.
One of the many mysteries AMS was designed to explore is what happened to the anti-matter that must have been created in the big bang. Scientists believe equal amounts of matter and anti-matter were produced, but for some reason the universe seen by humans is dominated by normal matter. Or at least the nearby universe.
"If the universe comes from a big bang, before the big bang it is vacuum," Ting told reporters recently. "Nothing exists in vacuum. So in the beginning, you have (negatively charged) electron, you must have a (positively charged) positron so the charge is balanced. So you have matter, you must have antimatter, otherwise we would not have come from the vacuum.
"So now the universe is 14 billion years old, you have all of us, made out of matter. The question is, where is the universe made out of antimatter?"
Dark matter, the mysterious, as-yet-undetected material believed to provide the glue--gravity--needed to hold galaxies and clusters of galaxies together, is believed to make up a quarter of the universe compared to the 4 percent made up of the normal matter familiar to human senses. The rest is believed to be in the form of dark energy, a repulsive force that appears to be speeding up the expansion of the universe.
While AMS cannot directly detect dark matter, it can detect the particles that would be produced in dark matter collisions.
Whatever AMS discovers, scientists will have plenty of data to work with. Some 25,000 particle detections per second are expected during normal operations