In this paper, we describe the first multi-frequency synthesis observations of blazar 0059+581 made with the Radioastron spaceground interferometer in conjunction with the Korean VLBI Network (KVN), Medicina and Torun ground telescopes. We conducted these observations to assess the spaceground interferometer multi-frequency mode capability for the first time.

The first Space-VLBI project, VSOP, started successfully with the launch of the dedicated space-VLBI satellite HALCA in 1997. The project has been in scientific operation in the 1.6 GHz and 5 GHz bands, and studies have been done mainly of the jet phenomena related to active galactic nuclei. A second generation space- VLBI project, VSOP-2, has been planned by the working group formed at ISAS/JAXA with many collaborators. The spacecraft is planned to observe in the 8, 22 and 43 GHz bands with cooled receivers for the two higher bands, and with a maximum angular resolution at 43 GHz (7 mm) of about 40 micro-arcseconds. The VSOP-2 satellite will also have the capability of the phase-reference and full polarization observations, which will produce more powerful results than those of the VSOP project. Far-future space-VLBI projects following VSOP and VSOP-2, have a large potential to achieve enough resolution and sensitivity to satisfy astronomers in future.

The VLBI Space Observatory Program (VSOP) is a worldwide project of one radio telescope in space with many ground radio telescopes. The concerted space VLBI network enables us to reveal high resolution and high quality images of radio sources. The space radio telescope is anticipated to be launched in January/February 1997, and collaborative observations have been coordinated. The basic parameters of the system and present status are given.