In about four hours, the Endeavour space shuttle is scheduled to launch from the Kennedy Space Center on its final mission, carrying with it what will be the largest physics experiment to blast into space.
The Endeavour will deliver to the International Space Station the Alpha Magnetic Spectrometer experiment. AMS-02 will bring scientists a new understanding of the makeup of the universe by collecting information from subatomic particles accelerated to energies far beyond those attainable by a man-made particle accelerator.
Astrophysicists postulate that the explosions of stars and other dramatic events in space release high-energy cosmic rays, which can travel for hundreds of millions of light years before reaching Earth. Once the rays collide with Earth’s atmosphere, they can be absorbed or break into showers of particles. Physicists are sending AMS-02 into space in order to catch cosmic rays before that happens.
AMS-02 will search for the unexpected, but scientists have a few items on their wish-lists for the detector, including primordial antimatter and dark matter particles.
Primordial antimatter is antimatter created during the big bang. Scientists think the big bang should have created equal amounts of matter and antimatter. When matter and antimatter meet, they annihilate into particles of light. But the universe as we know it is made almost entirely of matter. If AMS-02 detected antimatter particles in cosmic rays, it could mean that primordial antimatter still exists in abundance; we just haven’t found it yet.
Dark matter is matter that exerts a gravitational pull but does not absorb or emit light. The behavior of galaxies and the way we see them lead scientists to believe that almost a quarter of the universe is made up of dark matter. However, they have yet to detect dark matter particles. Some theories state that dark matter could be made up of particles called neutralinos. If these particles exist, they could collide with one another and produce excesses of charged or neutral particles the AMS-02 could detect.
AMS-02 will collect between 2,000 and 2,500 events per second and is scheduled to remain in orbit at the space station for at least a decade.
About three and a half days after today’s lift-off, the shuttle will reach the same orbital configuration as the International Space Station about 200 miles above the Earth. Once it has docked there, astronauts will remove the detector from the shuttle cargo area and attach it to the space station in an extraterrestrial hand-off using two giant robotic arms – one attached to the Endeavour and the other attached to the ISS. Less than an hour after they secure AMS and hook it up to the space station’s electrical supply, the detector will be able to start sending data back to Earth.