CALET, launched to the International Space Station in August 2015, is a calorimeter to measure cosmic rays and has been accumulating scientific data for over six years. CALET measured the spectra of the cosmic-ray iron and nickel from 10 GeV/n to 2.0 TeV/n and 8.8 GeV/n to 240 GeV/n, respectively. The tables of the spectra measured by CALET are open to the public via DARTS in April 2022.
Despite cosmic-ray nickel being much less abundant than iron, the unprecedented measurement was able to confirm that both elements have very similar fluxes in shape and energy dependence. This suggests that their origin, acceleration, and propagation might be explained by invoking an identical mechanism in the energy range explored so far. These results were published in Physical Review Letters on June 14, 2021, for iron, and April 1, 2022, for nickel, respectively.