Russian Hydrogen Masers for Space Applications

“VREMYA-CH” JSC was founded 20 years ago by specialists who had a big experience in hydrogen masers developing. Currently “VREMYA-CH” is a leader in hydrogen masers production both for ground-based and space applications. Main company’s activity in space applications results are brief summarized in three chapters of the paper. The first chapter describes the active hydrogen maser that has been developed for the space radio observatory “RADIOASTRON” (project “Spectr-R”) [1]. It was successfully launched on July 18 2011 with two produced by “VREMYA-CH” active hydrogen masers on board. The signal of this maser is used as a high stable reference for the on-board scientific equipment till now. The second chapter describes on-board passive hydrogen maser developing for Russian Global Navigation Satellite System (GLONASS), its design features and the ground testing results. Short term (one second) stability 7×10-13 as well as long term (one day) stability 5×10-15 allows improving GLONASS based timing and positioning in the future. A new active hydrogen maser generation for space observatory “Millimetron” (project “Spectrum M”) is under development now. This mission will enable astronomers to observe the Universe with unprecedented sensitivity and angular resolution. The third chapter shortly describes the new maser specifications and main design features.