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)
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.
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 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 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.
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.
The ARISE (Advanced Radio Interferometry between Space and Earth)
mission has been proposed by JPL and NRAO.
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)