HALCA, the first dedicated satellite for space VLBI, was launched
in February 1997, and VSOP observations have been successfully
undertaken at 1.6 and 5 GHz. The near-future VSOP-2 mission is
planned to have frequency bands of 8, 22, and 43 GHz, with dual
polarization, a 1 Gbps downlink bit-rate, and a phase-referencing
capability. The mission proposal was submitted to ISAS/JAXA in
September 2003, with the earliest possible launch, if approved, in
2012. There must be other missions farther into the future, and mm
and sub-mm space VLBI must be realized as the ultimate high
resolution imaging instrument over the electro-magnetic spectrum.
ALMA and SKA can also play important roles for space VLBI.