High-energy cosmic rays from across the galaxy will be detected on the International Space Station, thanks to a new observatory delivered on Monday.
The CALorimetric Electron Telescope (Calet) was delivered by the fifth flight of the Japan Aerospace Exploration Agency’s HTV, or Kounotori (“white stork”) spacecraft, and will now be attached to an external platform on Kibo, the Japanese experiment module, using a robot arm.
Cosmic rays are charged particles arriving from space at nearly the speed of light. Calet will measure the intensity of electrons and atomic nuclei, some with energies much higher than the Large Hadron Collider can produce on Earth. It will also monitor gamma rays.
One goal of mission scientists in Japan, Italy and the US is to pinpoint nearby sources of cosmic rays. The remains of exploded stars are thought to be responsible, and possible candidates include the Vela and Cygnus Loop supernova remnants.
Another mystery to be investigated is dark matter, the as-yet-unidentified material that makes up around 85% of mass in the universe. If dark matter particles annihilate when they collide with each other, the electrons and anti-electrons produced could be detected by Calet.
Other cargo arriving on HTV-5 this week included test tubes for collecting blood samples from the US astronaut Scott Kelly. He will undergo medical tests at the same time as his identical twin brother on Earth as part of the Twins study into the effects of spaceflight on human genes.
