The HALCA (Highly Advanced Laboratory for Communications and Astronomy), also known as MUSES-B before launch and Haruka after launch, is an 8 meter diameter radio telescope satellite which was used for Very Long Baseline Interferometry. It is in an orbit with an apogee altitude of 21,400 km and a perigee altitude of 560 km. The elliptical orbit allowed imaging of celestial radio sources by the satellite and ground based telescopes, with good (u,v) plane coverage and high resolution. The orbit ha… (More on Halca)