Within this project, we plan the next generation of muonic atom spectroscopy experiments aiming at a further improvement on the precision of the Lamb shift by a factor of five and a first-time measurement of the ground state hyperfine splitting in muonic hydrogen to a relative precision of 1 ppm, around two orders of magnitude better than the current precision of the theory. Furthermore, it is planned to perform precision X-ray spectroscopy on Z>2 light nuclei starting with lithium using magnetic metallic microcalorimeters (MMCs).