Already for seven years the SPEKTR-R spacecraft has been operating in orbit with a 10-meter radio telescope onboard. This space radio telescope together with ground-based telescopes forms a ground-space interferometer, which provides studies of space radio sources with a record angular resolution of up to 10 millionth of an arcsecond. This article provides an overview of scientific results obtained during the last two years of RADIOASTRON mission operation (2016-2018). The high brightness temperature detected by RADIOASTRON interferometer in source В0529+483 is discussed taking into account the influence if interstellar scattering. The characteristics of ultra-compact blazar AO 0235+164 have been studied by means of RADIOASTRON ground-space radio interferometer observations involving multi-frequency VLBA and EVN observations, as well as observations performed by single antennas monitoring. It is shown that in steady phase the brightness temperature of core of 3С273 quasar is a hundred times lower than in high activity phase in 2013, when the value of 1.4x1013K was obtained in the source reference system. The brightness temperature in the steady phase was even ten times lower than it should be for the case of equidistribution. Due to the unprecedented resolution of the RADIOASTRON terrestrial space interferometer, it was possible to show that the base of the jet in the nucleus of the galaxy NGC1275 (3C 84) was wide (about a thousand gravitational radii) and had a cylindrical shape. This may mean that at least the outer part of the jet is triggered by an accretion disc. The detection of compact maser features in the source of mega-maser radiation in the galaxy NGC 4258 imposes strict limits on the degree of maser saturation and on the pumping processes. Moreover, these compact areas masering regions are very likely to have a magnetic field with a simple structure. This can provide the ability to estimate the magnetic field strength by its polarization properties. Two unresolved spots smaller than 15 pas in angular extent were found in the massive star-forming region Cepheus A. This is the smallest angular structure ever observed in a Galactic maser, the linear size of these spots is smaller than the diameter of the Sun. The observed structure most likely can be explained in the model of turbulent vortices shed by an obstacle in a flow (i.e. Kármán vortex street). The fine structure of giant pulses from pulsar in a Crab Nebula was studied, which indicates the generation of radio radiation in the magnetosphere of a neutron star in the mode of a super strong electromagnetic wave. Using a thin scattering screen model the distances to the effective screens were determined along the line of sight to several bright pulsars. The model of uniform radio waves scattering is not suitable for any object. It was concluded that the observed scattering of radio waves occurs on relatively compact plasma layers in our Galaxy.
