HALCA

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Japanese space radio telescope

title: "HALCA" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["radio-telescopes", "space-telescopes", "satellites-of-japan", "spacecraft-launched-in-1997"] description: "Japanese space radio telescope" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/HALCA" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Japanese space radio telescope ::

::data[format=table title="Infobox spaceflight"]

Field	Value
name	HALCA
names_list	MUSES-B
VSOP
Haruka (はるか)
image	Haruka HALCA VSOP MUSES-B.jpg
image_caption	HALCA after the final assembly during a solar battery check at Uchinoura
image_alt
image_size
mission_type	Astronomy
operator	ISAS
COSPAR_ID	1997-005A
SATCAT	24720
website
mission_duration	8 years, 9 months, 18 days
manufacturer	NEC Toshiba Space Systems
launch_mass	830 kg
dimensions	1.5 x
power
launch_date
launch_rocket	M-5-1
launch_site	Kagoshima M-V Pad
disposal_type	Decommissioned
deactivated
orbit_reference	Geocentric
orbit_regime	Highly elliptical
orbit_semimajor	17259 km
orbit_eccentricity	0.5999671
orbit_periapsis	533.5 km
orbit_apoapsis	21244.1 km
orbit_inclination	31.1880 degrees
orbit_period	376.1 minutes
orbit_RAAN	127.6566 degrees
orbit_arg_periapsis	143.9533 degrees
orbit_mean_anomaly	358.3371 degrees
orbit_mean_motion	3.82867831 rev/day
orbit_epoch	28 April 2016, 09:56:58 UTC
orbit_rev_number	26766
apsis	gee
telescope_type	Mesh antenna
telescope_diameter	8 m
telescope_wavelength	1.3, 6, 18 cm (radio)
::

| name = HALCA | names_list = MUSES-B VSOP Haruka (はるか)

| image = Haruka HALCA VSOP MUSES-B.jpg | image_caption = HALCA after the final assembly during a solar battery check at Uchinoura | image_alt = | image_size =

| manufacturer = NEC Toshiba Space Systems | launch_mass = 830 kg | dimensions = 1.5 x | power =

| launch_date = | launch_rocket = M-5-1 | launch_site = Kagoshima M-V Pad

| disposal_type = Decommissioned | deactivated =

| telescope_type = Mesh antenna | telescope_diameter = 8 m | telescope_wavelength = 1.3, 6, 18 cm (radio) HALCA (Highly Advanced Laboratory for Communications and Astronomy), also known for its project name VSOP (VLBI Space Observatory Programme), the code name MUSES-B (for the second of the Mu Space Engineering Spacecraft series), or just Haruka ("far away, distant") was a Japanese 8 meter diameter radio telescope satellite which was used for Very Long Baseline Interferometry (VLBI). It was the first such space-borne dedicated VLBI mission.

History

It was placed in a highly elliptical orbit with an apogee altitude of 21,400 km and a perigee altitude of 560 km, with an orbital period of approximately 6.3 hours. This orbit allowed imaging of celestial radio sources by the satellite in conjunction with an array of ground-based radio telescopes, such that both good (u,v) plane coverage and very high resolution were obtained.

Although designed to observe in three frequency bands: 1.6 GHz, 5.0 GHz, and 22 GHz, it was found that the sensitivity of the 22 GHz band had severely degraded after orbital deployment, probably caused by vibrational deformation of the dish shape at launch, thus limiting observations to the 1.6 GHz and 5.0 GHz bands.

HALCA was launched in February 1997 from Kagoshima Space Center, and made its final VSOP observations in October 2003, far exceeding its 3-year predicted lifespan, before the loss of attitude control. All operations were officially ended in November 2005.

A follow-up mission ASTRO-G (VSOP-2) was planned, with a proposed launch date of 2012, but the project was eventually cancelled in 2011 due to increasing costs and the difficulties of achieving its science goals. It was expected to achieve resolutions up to ten times higher and up to ten times greater sensitivity than its predecessor HALCA.

The cancellation of ASTRO-G left the Russian Spektr-R mission as the only then operational space VLBI facility. Spektr-R stopped operating in 2019.

Antenna

The large 8 meter antenna was designed to unfold in space as the unfolded configuration did not fit inside the rocket fairing. The antenna was a metal mesh of 6000 cables. To form an ideal shape the length of the cables were adjusted on the backside of the antenna. One concern was that the cables could entangle. The deployment of the main reflector started on February 27, 1997. The deployment was done over three hours on the first day and was completed in 20 minutes during the next day.

Highlights

Observations of hydroxyl masers and pulsars at 1.6 GHz
Detection of interference fringes for quasar PKS1519-273 between HALCA and terrestrial radio telescopes
Routines imaging of quasars and radio galaxies etc. by means of experimental VLBI observations with HALCA and terrestrial radio telescope networks

Gallery

Haruka HALCA VSOP MUSES-B deployment test.jpg|Haruka during a deployment test Haruka HALCA VSOP MUSES-B launch.jpg|Launch of Haruka on board of a M-V rocket 1.6 GHz image of M87, VLA and VLBA + HALCA.jpg|The large image shows M87 as observed with the VLA, the insert shows observations with the VLBA and HALCA VSOP J1927+7358.gif| Multi-epoch observations of the quasar VSOP J1927+7358, observed with VSOP between 1997 and 2001 Animation of HALCA around Earth.gif|Animation of HALCA around the Earth

References

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::