A few years ago, a program for development of space instrumentation for soft X-ray astronomy has been initiated at MPI. It includes the design and fabrication of imaging X-ray telescopes which is done in close cooperation with Carl Zeiss/W.-Germany. After an extensive survey of various materials and polishing techniques applied to flat mirror samples, first paraboloidal mirrors were built each having a frontal diameter of 15 cm and a length of 1 m. A bundle of 12 such mirrors was flown twice on Aries rockets. The next step was the design and production of a Wolter type I telescope compatible with being used on a Skylark or Black Brant rocket. Actually, three of these telescopes were built. The mirror material is aluminium, plated with kanigen and coated with a reflecting gold layer. Each has an aperture diameter of 32 cm and a focal length of 143 cm. They were tested in MPI's short beam X-ray test facility and show nominal reflectivity, on-axis angular resolution of 5 arc sec (FWHM), and extraordinary low surface scattering of 6 I at 1 keV. Currently, a nested 80 cm diameter Wolter type I telescope of 240 cm focal length is being designed. The mirrors will be made from zerodur, a glass ceramic which has excellent thermal properties, low residual mechanical stresses as opposed to aluminium, and the ability to be polished to high surface finish. X-ray tests of the telescope will be performed in MPI's long beam (130 m) facility just under construction.