A Larger-Than-Earth Radio Telescope

Yesterday afternoon, Japan's Institute for Space and Astronautical Science (ISAS) launched a novel spacecraft that is designed to work in tandem with ground-based radio telescopes and boost their resolution as much as threefold. If the new satellite, a radio antenna dubbed MUSES-B, operates as planned, it's expected to provide a closeup look at a host of objects, including the most powerful objects in the universe, solar-system-sized regions at the centers of distant galaxies that put out the energy of billions of stars.

Radio astronomers have high hopes for the MUSES-B, which was launched from the Kagoshima Space Center, at the southern tip of the island of Kyushu, aboard the first of ISAS's new M-5 series rocket. The satellite is the first space-based antenna dedicated to very long baseline interferometry, a technique whereby astronomers combine signals from widely spaced antennas, generating images as sharp as if they were produced by a single instrument with a huge collecting area. In its highly eccentric orbit, ranging from 1000 to 20,000 kilometers above Earth, the $90 million MUSES-B will coordinate its observations with up to 10 ground-based telescopes spread around the globe. Says Hisashi Hirabayashi, project scientist for ISAS: "This will be the first mission ever in the field of radio astronomy to [have] a synthetic-aperture radio telescope bigger than the Earth."

The project will require some impressive choreography, involving five tracking and data-relay stations, to focus this constellation of instruments on the same objects with split-second timing. If successful, astronomers expect the instrument to provide a dazzling look at everything from the intense energy sources at the centers of some galaxies--thought to consist of black holes surrounded by rotating rings of gas--to the evolving shapes of exploding supernovae.