On Saturday, Japan lost contact with its newest space telescope, called Hitomi or ASTRO-H. The telescope, which includes an instrument from NASA, was intended to study the high-energy universe in X-rays and gamma rays, and observe such objects as supermassive black holes and galaxy clusters. Radar observations Sunday indicated that Hitomi, which launched on February 17, is in at least five pieces—and a plot of its orbit revealed a dramatic change on March 26, the date JAXA lost contact with the spacecraft. That means, says astrophysicist Jonathan McDowell, that some kind of “energetic event” has occurred—something more than a simple...