HALCA, also known for its project name VSOP, or the code name MUSES-B, is a Japanese 8 meter diameter radio telescope satellite which was used for Very Long Baseline Interferometry. It was the first such space-borne dedicated VLBI mission. 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 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. Wikipedia [ - ]

HALCA, also known for its project name VSOP, or the code name MUSES-B, is a Japanese 8 meter... [ + ]