The Alpha Magnetic Spectrometer (AMS), worth $2 billion, was placed outside the International Space Station (ISS) on Thursday. The device will be used to discover new forms of matter in outer space, NASA said.

Endeavour astronauts used robotic arms to place the instrument which weighs about 7.5-tons. The device was mounted on one of ISS’s metal truss where it will operate as long as the space station will be there.

The spectrometer has been programmed to read through high energy cosmic particles for signs of antimatter and dark matter which a normal telescope fails to capture.

AMS has a powerful built-in magnet to direct cosmic rays through a series of detectors which may have electrical charges and unknown energy levels. The data will be processed at a rate of 25,000 times per second by computers onboard and then sent to scientists.

The Endeavour astronauts are arranging for the first of the four spacewalks for preservation and servicing of the space station on Friday.

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