A Short History of Space VLBI

Last modified: October 1998

Early discussions A review of some of the early discussions about Space VLBI is given by B.F. Burke in IAU Symp. 110 `VLBI and Compact Radio Sources' p. 397 (1984)
QUASAT The QUASAT concept was originated at JPL in the early 1980s, and proposed to ESA as a joint ESA/NASA mission in 1982. The proposal called for 15m class antenna with observing bands at 0.3, 1.6, 5 and 22 GHz. The QUASAT proposal reached Phase-A stage before losing out in 1988 to the ESA Huygens probe for the Cassini mission.
TDRSS Trials of the orbiting VLBI concept were made using a Transfer and Data Relay Satellite System antenna between 1986 and 1988. Using a 4.9m diameter TDRSS antenna and the 64m ground radio telescopes at Usuda (Japan) and Tidbinbilla (Australia), fringes were successfully detected at 2.3 GHz and 15 GHz for a number of sources.
RadioAstron RadioAstron was first proposed in the mid-1980s. RadioAstron contains a solid-panel 10m diameter dish, and will observe at 0.3, 1.6, 5 and 22 GHz bands. The RadioAstron orbit will have a perigee of about 5000km and apogee of about 80000km, making it an ideal probe of high brightness temperature sources. RadioAstron is scheduled for launch in several years time. For more details see the RadioAstron home page.
VSOP VSOP arose out of discussions in Japan in the early 1980s. An official proposal was made to ISAS in March 1987. The MUSES-B satellite was launched on the first flight of ISAS's new M-V rocket on 12 February 1997, and the satellite renamed HALCA after launch. Further details are given in the Milestones and Goals page.
IVS A proposal for a second generation space VLBI mission, the International VLBI Satellite, was made in response to an ESA call for new mission ideas in 1989. IVS was planned to have a much wider spectral coverage (4.5-8.5, 15-23, 42-63, 86-120 GHz, and possibly also 218-222 GHz bands), and a 20m class antenna.
ARISE The ARISE (Advanced Radio Interferometry between Space and Earth) mission has been proposed by JPL and NRAO.
VSOP-2 A working group has been formed in Japan to study the possibilities for a follow-up mission to HALCA. The project, currently dubbed simply VSOP-2, would be considered for a launch sometime after 2005. (Cancelled)