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" (はるか))[2] was a Japanese 8 meter diameter radio telescope satellite which was used for Very Long Baseline Interferometry (VLBI).

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.

[3] 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.

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

To form an ideal shape the length of the cables were adjusted on the backside of the antenna.