The main technical solutions implemented in the Spektr-R observatory (RadioAstron) and the scientific results obtained during its orbital operation from 2011 through 2019 are reviewed. General characteristics and research objectives of the Millimetron (Spectrum-M) space observatory, a development of the Spectrum-R project in the submillimeter wavelength range, are outlined. The launch of Millimetron is scheduled for the early 2030s. Research programs of both projects are led by the Lebedev Physical Institute of the Russian Academy of Sciences.

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Keywords: radio astronomy, submillimeter astronomy, Spektr-R, RadioAstron, Spektr-M, Millimetron, radio interferometry, active galactic nuclei, jets, quasars, pulsars, masers, galaxies, supermassive black holes, wormholes, cosmic microwave radiation, interstellar medium, water in the Galaxy PACS: 07.87.+v, 95.55.−n, 98.80.Es (all) DOI: 10.3367/UFNe.2024.03.039662 URL: https://ufn.ru/en/articles/2024/8/c/ Citation: Likhachev S F, Larchenkova T I "From the Spektr-R project to the Spektr-M project: milestones in space radio astronomy" Phys. Usp. 67 (8) (2024) Received: 20th, February 2024, revised: 12th, March 2024, accepted: 13th, March 2024 Оригинал: Лихачёв С Ф, Ларченкова Т И «От проекта "Спектр-Р" к проекту "Спектр-М": вехи космической радиоастрономии» УФН 194 814–825 (2024); DOI: 10.3367/UFNr.2024.03.039662