Erich Rudolf Alexander Regener (12 November 1881 – 27 February 1955) was a German physicist known primarily for the design and construction of instruments to measure cosmic ray intensity at various altitudes. He is also known for predicting a 2.8 K cosmic background radiation, for the invention of the scintillation counter which contributed to the discovery of the structure of the atom, for his calculation of the charge of an electron and for his early work on atmospheric ozone. He is also credited with the first use of rockets for scientific research.