The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) is a payload developed by an international collaboration involving Italy, Germany, Russia, Sweden and the USA, and launched on June 15th, 2006, on board the Russian satellite Resurs-DK1. The main scientific objective of PAMELA is to precisely measure the cosmic-ray fluxes of various elements for energies from tens of MeV up to several hundred GeV.

The PAMELA experiment has found an excess of positrons in the cosmic rays, which could be a signature of dark matter annihilation or decay. However, there are other possible explanations for the excess, such as pulsars or supernova remnants. Further observations are needed to determine the source of the excess positrons.

If the excess positrons are due to dark matter, it would be the first direct evidence of dark matter. Dark matter is a hypothetical type of matter that does not interact with electromagnetic radiation, and is thought to make up about 27% of the universe. The existence of dark matter is inferred from its gravitational effects on visible matter, but it has never been directly detected.