The Alpha Magnetic Spectrometer (AMS-02) is a particle physics module mounted on the ISS. It is designed to detect and measure antimatter in cosmic rays and search for evidence of dark matter.
The instrument has been called “the most sophisticated particle detector ever sent into space”, and is considered by many to have the best chance of discovering evidence for the existence of dark matter. Dark matter is invisible matter that although cannot be directly detected, is believed to make up 23% of the Universe. Along with dark energy, it means that just 4-5 percent of the Universe is made up of visible matter, like the stars we see at night.
The 14,809 lb (6717 kg) module was launched by the Space Shuttle Endeavour for STS-134 on May 16 2011 and installed 3 days later on the 19th. AMS-02 is located on top of the Integrated Truss Structure, on a section known as USS-02. The mission has so far lasted almost 4 and a half years, and is expected to last for at least another five years, bring a full mission duration to a decade.
Following a year of data collection the AMS-02 had recorded over 18 billion cosmic ray events. One of the key results produced from this data has been the theory that positrons originate from the annihilation of dark matter particles in space. However, Professor Samuel Ting warned that although this theory is consistent with the data collected, it is “not yet sufficiently conclusive to rule out other explanations”. The experiment is just one example of many that proves the ISS is an incredible scientific outpost that is beneficial for the advancement of scientific discoveries.
On October 28 astronauts Scott Kelly and Kjell Lindgren conducted a spacewalk to install a new thermal cover for the AMS. The covers provide thermal performance for parts of the system that have been operating for longer than their life span of 3 years.